Hatch Covers - Operation, Testing & Maintenance by Mike Wall

The correct operation, care, and maintenance of hatch covers are critical to a vessel's safety and its ability to carry cargo without damage.

The book is intended for the care, maintenance, operation, and inspection of hatch covers, e.g., deck officers, deck ratings, superintendents, and surveyors.

This is 'on-the-job training' or a specifically designed short course. This book tries to cover as many of the designs as you are likely to meet, together with a few you may not. It is hoped that the chapters that reveal the many and varied defects will enable you to avoid the mistakes that others have clearly made.

2. Hatch Covers
Operation, Testing and Maintenance
by
Mike Wall
FCMS, FIMarEST, CMarTech, MllMS, NAMS-CMS
Managing Director and Principal Consultant
Kiwi Marine Consultants Ltd
Hoi:ig Kong
A Witherby Seamanship Publication
~,Seamanship
~~ lliHUiHIHIHI
WITH ERBY~
PUBLISHING

3. -a:c Covers -Operation, Testing and Maintenance
First published 2008
ISBN 13: 978 1 85609 344 6
British Library Cataloguing
in
Publication Data
Wall, Mike
Hatchcovers Operation, Testing and Maintenance
1. Hatch covers I. Title
623.8'6
ISBN-13: 9781856093446
© Witherby Seamanship International Ltd 2008
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or
transmitted
in any form or by any means,
electronic, mechanical, photocopying, recording or
otherwise, without the prior permission
of the
publishers. ·
Notice of Terms of Use
While the advice given in this book (Hatch Covers Operation, Testing and Maintenance) has
been developed using the best information currently available, it is intended purely as guidance
to
be used at the user's own risk. Witherby
Seamanship International accepts no responsibility
for the accuracy of any information or advice given in the document or any omission from the
document or for any consequence whatsoever resulting directly or indirectly from compliance
with or adoption of guidance contained in the document even if caused by failure to exercise
reasonable care.
This publication has been prepared to deal with the subject of Hatch Covers and Hatch Cover
Testing. This should not however, be taken to mean that this publication deals comprehensively
with all the issues that will need to be addressed or even, where a particular issue is addressed,
that this publication sets out the only definitive view for all situations.
The opinions expressed are those of the authors only and are not necessarily to
be taken as the
policies or views of any organisation with which he or they have any connection.
Published in 2008 by
Witherby Seamanship International
4 Dunlop Square
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Livingston EH54 8SB
United Kingdom
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No:
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www.witherbyseamanship.com
Printed and bound by Bell & Bain Ltd., Glasgow
[58971]
ii

4. Preface
The correct operation, care and
maintenance
of hatch covers are
critical to a
vessel's safety and its ability to carry cargo
without damage. Whilst there are currently
two small handbooks, viz,
A Master's Guide to Hatch Cover
Maintenance
by Eric Murdoch, Director of
Loss
Prevention, Charles Taylor & Co Ltd.
Published by The Standard P&I Club
Holds and Hatch Covers. Published by
A Bilbrough & Co Ltd.
both
of which can be found in many ship's
technical libraries, a publication search
revealed that there is no book that
comprehensively covers this subject.
The book
is intended for
all those associated
with the care, maintenance, operation and
inspection
of hatch covers, eg, deck officers,
deck ratings, superintendents and
surveyors. It is impossible for marine educational
establishments to cover all aspects of ship's
operations during ~tudy for certificate's of
competency. Some subjects have to be
sacrificed and generally covered as 'on the
job training' or as a specifically designed
short course. This
is one such subject.
It is
only when we first walk onto a ship and are
confronted with a hatch cover design that
our learning of the subject begins. Much the
same can be said
of most marine surveyors
who may not have served
on different types
of ships with various hatch cover designs.
They
also learn by experience.
Preface
It is only more recently that the International
Institute of Marine Surveying has introduced
the Diploma in Marine Surveying, of which
Cargo Surveying
is one option.
One of the
modules for this option of the diploma is on
hatch covers and hatch cover testing, written
by myself.
It was as a consequence of writing the
above module that the chance to enlarge it
into a book came about. As the book has
been written since the module was
published, it may be considered to include a
wider range and more up to date material.
The subject is large. While there are some
basic hatch cover designs, there are many
variations on them. There are also many
different permutations
of hatch cover type,
securing devices and methods for opening
and
closing. I have tried to cover as many of
the designs as you are likely to meet,
together with a few you may not. It is hoped
that the chapters that reveal the many and
varied defects will enable you to avoid the
mistakes that others have clearly made.
I hope that mariners and surveyors will find
this book valuable as a work of reference
when confronted with different hatch cover
designs and problems.
Mike Wall
iii

5. Hatch Covers -Operation, Testing and Maintenance
Foreword
Some years ago, as a Senior Master with
the World Wide Shipping Company, I proudly
stood on the bridge of our latest addition to
the fleet, a vast bulk carrier that was the
largest dry cargo ship in the world. We were
to embark
on a
prolonged voyage that was
to take us around the world and, as I stood
on the bridge, what struck me the most was
the seemingly endless row of hatches. My
attention was even more focused during our
voyage when,
on occasion, we encountered
appalling weather, with the seas breaking
over the bows and crashing down our decks
and watching after each encounter, the ship
rising again with the water streaming off the
hatch covers and our decks, but still all
secure.
The purpose
of the ship, the safe carriage of
the cargo, was
reliant on these covers, and
when the ship arrived
in port and the rumbling noise of 22 huge slabs of steel
opening revealed a dry and well preserved
cargo
we were very reassured.
I had at that
time been asked to write the new dry cargo
regulations for the fleet and in my
deliberations I had emphasised the need of
hatch cover maintenance and care. This was
based
on experience and the
literature about
this most important subject that was
available. The information available was
surprisingly sparse considering the vital
importance of hatch covers, not just for the
cargo but for the safety of the ship and
those onboard.
Too often during my career at sea
I have
joined ships to see the tell tale rust streaks
inside hatches, and the reliance on hatch
tape and sealant for the security of the
cargo. Now we have a book that for the first
time explains and details the complexities of
these vital parts of the ship's structure, and
the machinery, repairs and surveys required
to ensure their maintenance. Technical
books are not always the most easy to read
but this book
is.
It is well written, concise
and above all, understandable. This book is
essential reading for all Masters and Chief
iv
Officers at sea and those we rely on for
hatch surveys. Indeed, all those with any
interest
in the safe transportation of cargo
and the
structural safety of ships will benefit
from this book.
Captain Michael Lloyd, FNI

6. The Author
Mike Wall joined Cunard Line as a marine
engineer apprentice at the age
of
seventeen,
eventually reaching the rank of
Chief Engineer with service aboard many
different types
of
vessel.
During his career Mike obtained a Class 1
marine engineer's certificate
of competency,
a
Bachelor of Science in Maritime Studies
and Master
of Science degree in Shipping
and Maritime Studies. Experience was
gained
in most areas of shipping with eight
years as a
lecturer in Maritime Studies,
culminating in five years as Senior Lecturer
at Warsash College of Maritime Studies,
UK.
Twenty years experience was gained in hull,
machinery, cargo and condition surveys in
the USA, New Zealand, Fiji and South East
Asia,. Most
of this was as Managing Director
and
Principal Consultant for Kiwi Marine
Consultants Ltd, Hong Kong, for P&I Clubs,
Shipowners, Shipmanagers, Underwriters,
Admiralty Lawyers and other Principals.
Mike is also a qualified Mediator, registered
both
in the
UK and Hong Kong. ·
Mike is a regular contributor of shipping
technical articles to various maritime
publications and is currently editor of
FLASHLIGHT, the free emailed monthly
newsletter distributed to marine surveyors
around the world. Mike also organises the
annual 'Asian Marine Insurance and
Surveying Forum'.
'\" c
Author
v

7. Hatch Covers -Operation, Testing and Maintenance
Acknowledgements
A Master's Guide to hatch Cover
Maintenance
by Eric Murdoch, Director of
Loss Prevention,
Charles Taylor & Co Ltd.
Published by The Standard P&I Club
Holds and Hatch Covers. Published by A
Bilbrough & Co Ltd.
Ship Construction by D
J Eyres, MSc,
FRINA. Published by Heinemann, London.
MacGregor Group for photographs graphics
and information
on various hatch cover
types.
The
Nautical Heritage Association for their
report
on the Derbyshire inquiry.
www.nautical-heritage.org.uk/ derbyshire.html
Captain John Pearsall and Barry Thompson
for proof reading and their technical input.
Skuld for provision of case studies.
The various P&I Clubs who have given me
the opportunity to carry out many condition
surveys.
Finally, my wife, for her understanding and
patience during the writing
of this book.
vi

8. Contents
Contents
Preface iii
~ffi~~ ~
The Author v
Acknowledgements vi
1 Why Hatch Covers are Fitted to Ships 1
2 Background to the Design of Hatch Covers 7
3 Ship Construction to Accommodate Hatch Covers 11
"
r;
4.1
4.2
4.3
4.4
4.5
4.6
S"""ns for Different Cargoes
Bulk Cargoes
Containers
General Cargoes
Refrigerated Cargoes
Timber Cargoes
Other Cargoes
""'-· 111"'>.l" T\.I
5.1 Pontoon and Tarpaulin Covers
5.2 Direct Pull Covers
5.3 Folding Covers
5.4 Roll Stowing Covers
5.5 Side and Rolling Covers
5.6 Life and Roll Covers (Piggy-back)
5. 7 Sliding Tween-deck Covers
5.8 Pontoon Covers
5.9 Reefer Vessels
5.10 Other Sealing Systems
5.11 Other Hatch Cover Designs
5.12 Other Cleating Methods
6 The Differences Between Watertightness
,_ ....... ,,...,,...
6.1 Ram-nek Tape and Foam
7 Care and Maintenance of Hatch Covers
17
19
20
23
23
23
24
25
28
30
38
47
50
61
64
65
68
69
70
70
73
76
77
vii

9. Hatch Covers -Operation, Testing and Maintenance
8 Reasons for Hatch Cover Testing by
Various Organisations and the Role of the
II. C" .a. T f
8.1 National Based Survey Organisations
8.2 Classification Societies
8.3 Independent Surveyors
8.4 Insurance Surveyors
8.5 Cargo Surveyors
8.6 On/Off Hire Surveys
8. 7 Pre-purchase Condition Surveys
(' ,- I
.... '-latch Cover lesting Methods
9.1 Chalk Test
9.2 Light Test
9.3 Hose Test
9.4 Air Test
9.5 Putty or Moulding Clay Test
10 The lJse of Ultrasound Testing Equipment,
Principles and Operation of the Varied
,... .a. ,,.. '3 on the Market
10.1 What is Ultrasound?
10.2 Advantages of Ultrasound
10.3 The Equipment
10.4 Miscellaneous
10.5 Comparison of the Equipment
10.6 Hatch Cover Testing Protocols and Procedures
11 Client Approval ot ultrasound Testing Equipment and
,......
11.1 Client Approval
12 Common Defects Found when Hatch Cover Testing
13 Repairs
to Hatch Covers C"-e S
viii
Case Study 1: Hatch covers leaking in gale force winds
Case Study 2: Leaking hatch covers -damaged steel coils cargo
Case Study 3: Water ingress through hatch covers on a refrigerated vessel
Case Study 4: Port of refuge required
Case Study 5: Oil leakage from the hatch hydraulic system on to the cargo
Case Study 6: Water damage due to leaking hatch covers
Case Study 7: Alleged wet damage to frozen krill
Case Study 8: Water damage to fishmeal cargo
Case Study 9: Steel cargo damage -ship sweat and sea water
Case Study 10: Water soaked cargo
85
87
87
88
88
88
88
89
91
93
93
94
94
95
97
99
101
101
105
105
108
113
115
119
125
131
133
137
145
147
149
151
153
155
159
161

10. Ar-en s
Appendix 1: Resolution MSC 169(79)
Standards for Owners' Inspection and Maintenance of
Bulk Carrier Hatch Covers
Appendix
2:
Table Showing Comparison of Ultrasound Equipment
Index
Contents
165
167
171
173
ix

12. 1 Why Hatch Covers
are Fitted
to
Ships
A ship is basically a box that floats on water
and carries various cargoes for profit.
Merchant cargo vessels have cargo holds in
which the cargo is carried. To get the cargo
into the holds, there must be access through
the deck or sideshell. Unfortunately, cutting
holes or hatches in the deck will cause a
loss of longitudinal strength and allow water
into the holds. We therefore need to put
some 'lids' on the holes in the deck to
protect the cargo. These are known as hatch
covers.
The aim
of a hatch cover is to
allow as large
an access to the cargo holds as possible
while maintaining the strength and
watertighUweathertight integrity
of the vessel. Failure of the hatch covers and
breaching can cause damage to the cargo,
loss of stability and ultimate loss of the
vessel. Hatch covers must also meet the
requirements
of the
SOLAS Convention, the
Loadline Convention, Classification Society
Rules and International Maritime
Organization (IMO) and International Labour
Organization (ILO) guidelines.
For each class of vessel there is a need to
provide efficient and effective, time saving
and secure, coverings for weather decks,
tween decks, vehicle decks, ro/ro doors, and
where appropriate, equipment related to the
movement of cargo
to, from and into spaces.
Why Hatch Covers are Fitted to
Ships
In the majority of cases the principle behind
the hatch covers
is to expose the greatest possible area. This is so that cargo can be
lifted into or out of its stowage position with
a minimum
of
horizontal movement. Also,
efficient hatch covers can reduce the time
spent
in ports preparing for work and
opening up/battening down cargo spaces.
The reader
should be aware that it is the
duty
of the Master to ensure that hatch
covers are watertight and
serviceable at all
times.
There
is now a wide choice of hatch cover
types
available to the shipowner. These are
commonly known as:
• Wire, chain, electric, hydraulically
operated
• end, side, folding, lift-off
• weather, tween deck
• flat, peaked top
• single, double skin, box, etc.
The type
of ship and its purpose determines
the type
of hatch covers. These
include the
modern multi-purpose cargo vessel, the roll
on/roll off ship, the dry cargo bulk carrier,
combination carriers, container/ro/ro
vessels, ferries, vehicle carriers as well as
many other different forms
of ship.
While
hatch covers must be watertight, they must
also provide an efficient and effective time
saving method
of access.
Hatch covers must be strong to resist the
dynamic forces exerted
by heavy seas which
Figure 1.1 -Hatch Cover Deformation at
Sea
(Courtesy of MacGregor Group)
3

13. Hatch Covers -Operation, Testing and Maintenance
may break over them. Heavy seas may also
cause a vessel to flex, ie hogging, sagging,
racking and twisting. Ships are not rigid
structures and are designed to be flexible to
minimise the stresses
on the
hull. Rolling
and beam seas may also cause sideways
movement
of the hatch covers. This means
that the covers must be
able to flex and
move slightly while retaining watertightness.
Watertight integrity
of the hatch covers in
the forward 25% of the
vessel is particularly
important as this is where sea loads are at
their highest.
Practical Demonstration
You may better understand why hatch
covers are fitted to ships
by carrying out a simple experiment.
You will need a water filled bath or trough, a
biscuit tin and enough pebbles or similar
weights to half fill the tin.
a. Take a 300 mm square, 100 mm deep,
empty square biscuit tin with lid and
apply pressure to one of the top edges.
The tin should generally maintain its
shape.
b. Now remove the
lid and again apply
pressure to one of the top edges. It will
be seen that the tin will 'rack' easily, such
that it can be completely crumpled.
c. Now fill a bath or trough with cold water
to a depth
of
300 mm.
d. Take the square biscuit tin and remove
the lid.
e. Place the tin, empty and without lid, in
the water. Depending on the thickness
and the density
of the tin
plate, the
biscuit tin should float at a draught of
about 5-10 mm.
f. Simulate heavy seas by stirring up the
bath water to create waves. The biscuit
tin should float without problem, with little
or no water entering it.
4
g. Heavy rain may be simulated using the
shower head. While water will have
entered the, tin and it will have become
slightly unstable, in still water there will
be no consequences. However, if the
water
is stirred up to
simulate waves,
there is more likelihood of more water
entering the tin, further reducing its
stability with the ultimate possibility of
sinking.
h. Remove the tin and empty it. Put it back
in the water.
i. Now place some weights in the tin,
eg large pebbles, to increase the draught
until there is approximately 40 mm of the
tin showing above the water level.
Ensure that the weights are fitted tight
into the tin to prevent them from moving
around.
j. Again,
simulate heavy seas by stirring up
the bath water to cre·ate waves. With the
lower freeboard it is easier for the waves
to break over and into the tin. You will
notice that as more water enters the tin,
it becomes more unstable, with draught
increased and freeboard reduced.
Eventually, smaller waves will be able to
fill the tin until it sinks.
k. Now empty and dry the tin completely.
Replace the lid and refloat the tin in the
bath water. Simulate rain with the shower
head and heavy seas
by stirring up the
bath water.
If the lid is secure, no water
will enter the tin and it will float without
problem.
I. Next add the weights back into the tin to
leave 40 mm of the tin protruding from
the water, and again replace the lid.
Simulate rain with the shower head and
heavy seas by stirring up the bath water.
If the lid is secure, no water will enter the
tin and it will float without problem, the
contents remaining
dry.
If there are leaks
in the lid, ie hatch cover, water will enter
the tin and it will eventually sink.
This demonstrates that fitting watertight
hatch covers to a ship will:

14. Prevent the ingress of water to the cargo
holds, with possible loss of stability and
ultimate loss of the vessel, her crew and
cargo
prevent wetting
of the cargo and
possible
cargo damage
prevent seawater spray which, combined
with
air, may
also cause significant
corrosion
of the
vessel's structure and
consequential reduction in strength.
Therefore, hatch covers are fitted to ships to
maintain watertight integrity and to protect
the ship, the crew and the cargo.
Why Hatch Covers are Fitted to
Ships
'.
5

16. 2 Background to the
Design of Hatch
Covers
This chapter is not intended to be a history
lesson, but it does provide some background
to the design
of hatch covers.
Ever since men first went to sea
in boats
they
realised that they could be used to
move cargoes. Some realised that they
could do this for profit and so the merchant
cargo vessel was born.
Initially, cargo was carried loose and
uncovered
in the bottom of a boat. However,
cargoes were wetted by rain or sea spray so
cargo began to be covered
in rudimentary
ways.
As wooden ships became
larger and
designs developed, so did the hold and
Moulded section
Background to the Design of Hatch Covers
hatch design
until eventually, the hatch
board and tarpaulin were developed and
fitted, as shown
in Figure 2.1. Note that the
hatch boards are
laid longitudinally between
hatch beams.
Although wooden hatch covers were the
original hatch covers for many vessels, they
are unlikely to be found in modern merchant
vessels. However, this arrangement is still
used today on smaller wooden vessels, such
as fishing boats and some smaller steel
coasters. The system is also used to a large
extent on European canal barges, with
aluminium covers replacing the wooden
hatchboards. While simple in use, the
combination
of wooden boards, beams, tarpaulins and wedges, and the time spent in
removing and replacing, not to mention
personal hazards, are no longer acceptable
on modern merchant vessels. However,
European canal barges have adopted a
small, longitudinally travelling gantry crane
Timber covers with
tarpaulins over
/
Flat
Wedge
Cleat
_..,,,. Heavy insert plate
in web at socket
-Web
Horizontal ,__/
stiffener
Deck
Half beam
Round bar
Cleat
Wedge 1 -
Coaming
Batten
Hatch
beam
section
, Plan At Horizontal Stiffener
Figure 2.1 -Diagram Showing Wooden Plank Hatchboards with Tarpaulin Cover
9

17. Hatch Covers -Operation, Testing and Maintenance
that efficiently lifts and stows the
transversely fitted metal cover panels.
Earlier timber constructed sailing ships also
had timber hatchboards covered by
tarpaulins. When ships were constructed of
steel and mechanically propelled, wooden
hatchboards with tarpaulin covers were still
being used. As steel ships became larger,
the timber hatchboards were replaced by
transverse steel pontoons covered by
tarpaulins. These are still used today on
some smaller bulk carriers. However, steel
pontoons are cumbersome and time
consuming to remove/replace.
With the development of larger steel ships
new methods had to be found to cover
hatches with systems that were quick and
easy to operate. The wire operated single
pull rolling hatch cover was developed to suit
this need and remained the most popular
until vessels became even bigger. It was
later modified with the addition of side
pulling chains. The development of hydraulic
systems contributed to the design of
hydraulically operated hatch covers, the first
being those lifted/lowered by hydraulic jacks
and operated by hydraulic rams forward and
aft. Not long afterwards, hydraulic hinges
were developed which, when applied to
hatch covers, resulted in even more deck
space saving .
. .
10
As bulk carriers became larger it was clear
that fore and aft folding covers were going to
be too heavy and cumbersome. Side sliding
hatch covers were developed, initially wire or
chain operated but further modified with the
hydraulic rack and pinion system later on.
This book covers most hatch cover designs
and the basics
of
closing devices and
discusses their continuing development.
However, with the rapid changes in
technology there is likely to continue to be
new developments.

19. 3 Ship Construction
to Accommodate
Hatch Covers
For cargo to be
loaded through the main
deck, a gap must be cut
in the main deck for
the hatch. As this is
large, the loss in ship's
strength must be replaced by additional
A. Transversely
Framed Deck
B. Longitudinally
Framed
Deck
Deck plating
Deck
Plating
Hatch coaming
Ship Construction to Accommodate Hatch Covers
stiffening and strengthening in the form of
robust hatch coamings with substantial
stays, together with additional underdeck
beams.
The ends
of the hatch must
also be rounded
off or 'filleted' to prevent sudden changes in
cross sections, which could create a 'stress
raiser' and cause tearing
of the main deck in
heavy weather:
Side frames
Hatch end beam
Figure 3.1 -Deck Construction in Way of Hatch Coamings
13

20. Hatch Covers -Operation, Testing and Maintenance
Radiused Hatch
Corner
Hatch
side
Deep Hatch
End
Beam (or Transverse)
~ Patent hatch cover
Offset bulb plate
Hatch
Offset bulb stiffener
Longitudinal
stiffener
Deck
Hatch
side
girder
Figure 3.2 -Additional Strengthening in way of Hatch Openings in the Main Deck
Coaming heights are
vital aspects of their
strength, weathertightness and
watertightness. Coaming height
is
also
determined by the operation of the hatch
covers and their stowage, together with the
nature
of the cargo carried.
Hatch coamings are fitted with vertical
coaming stays above deck and
horizontal
longitudinal stiffeners to assist with rigidity.
The stays can take various forms. The most
popular is the solid plate type, which often
has lightening holes through which deck
pipelines can pass, eg fire main, hydraulic
pipes, etc. Some coaming stays may be of a
girder form, providing greater space
between the stay and the coaming. Below
deck there are brackets or stays supporting
the coaming extension (see Figure 3.3).
14
The coamings
will also need various fittings,
eg stevedore ladders and platforms. The
coaming bar forms the flat upper face of the
coaming and carries the hatch cover weight,
transmitted via the hatch cover rollers when
opening/closing. The coaming bar may
accommodate the hatch cover bearing pads,
so the coaming and stays must be
of
substantial construction. The inner edge of
the coaming bar will be proud of the flat
coaming bar to form the inner drain channel.
It will also accommodate the sealing
mechanism and will need to have access for
hatch cover side and end cleats.
Once lowered in place, hatch covers must
be secured using the cleats to prevent
leakage. They must also be fitted with
drainage devices from cross joints and
coaming bar drain channels to prevent water

21. Hatch
coaming
Compression
Inner biar
drain Outer drain channel
channel & wheel trackway
r
r
Hold
Main deck
Figure 3.3 -Diagram Showing Coaming Bar
Arrangement
Ship Construction to Accommodate Hatch Covers
from entering the holds. As most ships trim
by the stern,
ie the after draught is deeper
than the forward draught, the coaming bar
drains are
usually situated at the after
corners, allowing any water, that has passed
by the rubber seal to drain away to the deck
(see Figure 3.5). These are a non-return
design to prevent external deck water
entering the drainage channel and, possibly,
the holds.
i--J...l_ ~ -
Figure 3.4 -Diagram Showing Quick Acting Cleat
(Courtesy of MacGregor Group)
15

22. Hatch Covers -Operation, Testing and Maintenance
Figure 3.5 -Hatch Cover Drain and Quick Acting Cleat
16

24. 4 Different Designs
for Different
Cargoes
The size and type of ship and the purpose
for which it is being used determines the
hatch cover type. The type
of cargo and
speed
of operation
will often determine the
design.
4.1
Bulk Cargoes
Bulk cargoes are considered to be primary
cargoes, ie the basic commodities to make
other products. These include:
Ore, eg iron, copper, aluminium
grain, eg corn, wheat, oats
coal and coke
cement clinker
concentrates, eg fertilisers, chemicals
· minerals, eg china clay, gypsum, Ilmenite,
rutile and zircon stands
timber,
eg wood·chips vegetable products, eg copra, sugar.
Side
T5T tank
plate
shell 11 Frames
Tanktop
-- -PU
Ca.-go
hold
Bottom shell
Section Through Bulk Carrier
Figure 4.1 -Bulk Carrier Midship Section.
Different Designs for Different Cargoes
These are
generally carried in ships called
bulk carriers, of a similar design to that
shown
in Figure 4.1.
The
vessel is provided with hopper plates at
each side. These help in raising the centre
of gravity of denser cargoes such as iron
ore. The topside tanks may be ballasted to
further raise the centre
of gravity when
carrying denser cargoes. The topside tanks
may, in some cases, be used for
loading
lighter grain cargoes. Grains are less dense
cargoes so the hold will be completely filled.
Grain cargoes may have a tendency to
liquefy and flow freely and to do so
in such a
large space could cause a substantial free
surface effect and loss of stability. The
topside tank plates and higher hatch
coamings assist
in reducing this effect. The
higher hatch coamings mean that more
cargo can
also be loaded. The hatch cover
width is approximately half the vessel's
breadth.
Bulk carriers are generally categorised as:
a. Mini-bulkers
Mini-bulkers are normally geared, ie they are
fitted with means to load and discharge the
cargo. Cargo access is commonly assured
by folding hatch covers, although stacking,
piggy back or lift-away types may be
adopted.
b. The handy sized
bulk carrier
This ship has a deadweight of up to
40,000 tonnes. It will usually have its own
cargo
gear, which
will either be derricks,
cranes or the more expensive gantry
equipment such as the Munck Loader:
Handysize and Handymax bulkers are
usually geared and feature folding hatch
covers. Very wide hatches are increasingly
specified to allow loading of non-bulk
cargoes such as steel coils and forest
products. Onboard cranes enable cargoes to
be loaded and discharged in ports with
limited infrastructure.
19

25. Hatch Covers -Operation, Testing and Maintenance
c. Panamax
These ships are of a size that can pass
through the Panama or Suez canals and are
known as Panamax bulk carriers. For
Panamax bulkers, most shipowners adopt
standardised cargo access and cargo
handling equipment. Vessels of this type are
normally equipped with side-rolling hatch
covers and are usually non-geared.
However, there may be provision cranes
situated aft
of the superstructure.
d. The Very Large
Ore Carrier (VLOC)
These ships are designed to carry heavy ore
or coal cargoes. They are specially
strengthened with double bottom
compartments underneath the hold that
raise the height
of the cargo to prevent the
ship from becoming
unduly stiff when
carrying the heavier iron ore. Sometimes
known as the Capesize bulk carrier, as they
cannot pass through the Panama or Suez
Canals and must pass around Cape Horn or
Cape of Good Hope to move between
oceans. VLOCs and other Capesize bulkers,
typically have holds served by side-rolling
hatch covers and are non-geared apart from
provision cranes.
Figure 4.2.
Typical Capesize Bulk Carrier.
20
e. Combination ships.
There are two types in this category, the
ore/oil carrier and the Oil/Bulk/Ore (OBO)
carrier. The ore/oil carrier is usually a very
large ship, over 150,000 tonnes dwt, with
ballast tanks that can also be used to carry
oil. The relationship between the hold and
tank space
is such that these ships can
carry a
full cargo of ore or oil. Ore/oil ships
can be used for whichever trade
is the most profitable at any one time, or they can
reduce unprofitable ballast time by carrying
different cargoes on different stages
of the
voyage.
The
Oil/Bulk/Ore (OBO) ships differ from the
larger ore/oil ships in that they can carry
either ore or oil in the same holds. This gives
the ship the advantage
of greater
hold
space to carry a wider range of bulk cargoes
than the ore/oil ship with smaller holds.
. When changing over from an oil to a dry bulk
cargo the holds must first be cleaned and
gas freed and the heating coils lifted. The
ships have to carry water ballast in their
holds and, to prevent free surface from
endangering stability, can only sail with their
holds full or empty. They have deep hatch
coamings and a liquid cargo must be filled
up into these spaces to reduce free surface
effect. The vessels tend to have side sliding
hatch covers fitted with ventilators.
4.2 Containers
Containers come in various shapes and
sizes and are used for many different
cargoes. They are generally grouped into
the following categories:
a. Feeder -ranging from 200 to
2,000 teu
The first and last link in the transport chain,
feeders transport cargoes that are
subsequently transferred to and from large,
long-haul container vessels bound for
worldwide destinations. For cargo handling
in ports with limited infrastructure, feeders

26. Figure 4.3 -Geared Panamax Container
Vessel with most Hatch Covers Removed
(Courtesy of MacGregor Group)
are often geared with two or three deck
cranes
of the
slim-line type to maximi·se
container stowage. "space.
b. Panamax -up to 5,000 teu
A class of container ship with a cargo
capacity
of up to
approximately 5,000 TEU,
designed with a maximum beam and
draught to transit the Panama Canal.
Customised lift-away (pontoon) hatch cover
sets are specified for all vessels with
capacities over 1,000 TEU. The 17 openings
of a 5,000 TEU vessel may typically have
50 panels, arranged in single, twin and
triple-panel configurations, depending on the
size
of the
individual hold. These vessels
may also be geared.
c. Post panamax
A class of container ship with a cargo
capacity exceeding 10,000 TEU. In a similar
manner to all large, long haul tonnage, post
Different Designs for Different Cargoes
panamax vessels have lift-away hatch cover
sets. Hatch cover sets for up to
21
holds,
comprising up to 80 panels, are arranged in
twin, triple, or four-panel configurations.
Rapid turnarounds
in port are
vital when
maintaining liner schedules. Cargo handling
for large, long-haul container ships, which
are generally non-geared, is provided at the
terminals by dockside gantry cranes.
However, feeder container ships are
equipped with deck cranes for cargo
handling in ports with limited infrastructure.
Feeders transport cargoes that are
subsequently transferred to and from large,
long-haul container vessels bound for
destinations worldwide.
Hatch covers will generally extend almost
the full width of the ship, except at the bow.
As the number of containers that these
vessels can carry is increasing daily, the
vessels are becoming larger and stack
heights becoming higher. This means that
the hatch covers must be strong enough to
take the higher loads. A single hatch cover
covering the full width of the vessel would be
too heavy to lift and stow. Consequently,
there may be three or four sections
athwartships, generally of a steel pontoon
design and double skin or box type. Small
container ships may have single skin covers.
Container vessels are generally gearless,
so the hatch covers are lifted by shoreside
cranes using 20 feet sockets positioned at
the centre
of gravity on the hatch cover
upper surface. Another
limiting factor in the
size
of the hatch covers is the
40 tonne safe
working load of most shoreside container
cranes.
Some container ships are described as
hatchless. However, this is a misnomer as
No 1 and 2 holds must have hatch covers.
These vessels also have a higher freeboard
to prevent further water ingress. Nos 1 and 2
hatch covers are
of the
steel pontoon type
and are again lifted by container cranes.
Containers may also be stowed in general
cargo vessels that have been designed or
21

27. Hatch Covers -Operation, Testing and Maintenance
22
Figure 4.4 -Geared Panamax Container Vessel with Hatch Covers in Place
(Courtesy of MacGregor Group)

28. modified to carry containers underdeck and
on the hatch covers. This means that the
hatch covers must be strong enough to take
the higher loads imposed by the container
stacks.
There
is a misconception among some ship
operators that container hatch covers do not
need to be weathertight or watertight. The
P&I Clubs tend to disagree and insist that all
hatch covers are watertight. Like other
vessels, container vessel hatch covers are
fitted with a sealing mechanism and locking
devices and do not rely on the weight of
containers on top to maintain the seal.
4.3 General Cargoes
General cargo vessels are becoming fewer,
with much general cargo now shipped in
containers. However, there are still some
general cargo and multi-purpose vessels in
service, which carry cargoes that cannot be
carried
in containers, eg,
heavy-lifts, break­
bulk, project cargoes.
These vessels may have fittings to load
containers on deck. They may also carry
project cargo or other heavy loads in holds,
on deck and on hatch covers. Consequently,
the hatch covers must be strong enough to
take these higher loads. These are generally
of the single skin type.
Multi-purpose vessels are designed to
handle and stow a variety of freight. This
may include forest products, manufactured
goods, heavy equipment, vehicles,
machinery, bagged goods, steel and food
products and containers. Some specialised
vessels combine general cargo with heavy
lift capabilities for transporting large,
awkwardly shaped components to refinery,
chemical processing and other plant
construction projects. Vessels of this type
are normally equipped with hatch covers
designed to bear heavy loads.
Different Designs for Different Cargoes
Weathertightness and cargo hold humidity
are important issues. For tweendeckers,
stowing length of the equipment must be
kept to a minimum.
4.4 Refrigerated Cargoes
With the
development of the reefer container
there are fewer bulk refrigerated cargo
vessels at sea today. While the hatch covers
are smaller and are not required to take
loads on top, they are still required to be
watertight and also to have a significant
amount
of
insulation.
4.5 Timber Cargoes
Timber is defined as loose timber, such
as individual planks of sawn timber, logs or
pit-props; or packaged timber, such as
bundles of sawn timber: Packaged timber
consists
of either
similar sized planks
forming a regular cuboid (regular packaged
timber) or random sized planks that do not
form a regular shape (irregular packaged
timber).
Timber may be stowed
in
holds and on deck.
Permanent and portable log stanchions,
together with chain and wire lashing, assist
in maintaining the cargo stow in a solid block
while preventing the cargo from falling
overboard.
A timber deck cargo stowed solidly in wells
has an effect that is similar to raising the
height
of the freeboard deck.
In this way the
assigned freeboard may be reduced and the
ship loaded to a deeper draught. A solidly
stowed, properly secured timber deck cargo
means that:
Water cannot flow freely on the weather
deck
greater protection is given to closing
appliances, such as hatch covers that
23

29. Hatch Covers -Operation, Testing and Maintenance
protect the weathertight and watertight
integrity
of the ship
the timber compensates for the
loss of
reserve buoyancy caused by the reduced
assigned freeboard. It is, therefore,
important that the timber cargo is solidly
stowed to the minimum height, as
specified
in the
regulations.
The timber rules state that the maximum
height
of timber during winter is not to
exceed one third
of the beam. This means
that, for a
vessel with a beam of 30 m, the
height
of the timber may be
10 m. With
some logs weighing in excess of 1 tonne the
loads on hatch covers can be significant, so
they must be strong enough to take such
loads. While some logs float, many of the
logs carried on timber carriers are of the
'sinker' type, ie with a density greater than
1.0, so hatch covers still need to be
watertight.
.
.
24
4.6 Other Cargoes
Liquid cargoes such as oil and chemicals
tend to be carried in tankers. These vessels
do not have hatch covers of similar type to
the other vessels mentioned above.
However, they do have various deck fittings,
including access hatches, all of which must
be watertight and gas-tight. Tanker access
hatches use the seal and compression bar
principle.
Roro vessels carry general cargoes on road
trailers that can be easily and quickly loaded
and discharged. These tend to be used on
short sea routes where port time takes up a
lot of the vessel's operating life. Roro
cargoes thus minimise port time and
maximise freight earning sea time. While
they tend to have side, stern or quarter
ramps only, som~ · smaller multi-purpose inter
island vessels may also have hatch covers.
Vehicle carriers have side, stern or quarter
ramps only. The ramp seal design is similar
to that of hatch covers, with compression
bars and rubber seals .

31. 5 Hatch Cover Types
There are a number of basic types of hatch
covers described below. These include:
Pontoon and tarpaulin
direct pull
folding
multi-folding -balanced
t multi-folding -foldlink and foldtite
piggy back or lift and roll
roll up or rolltite
side rolling
stacking covers
steel pontoon -lift away type.
There are many variations
of these basic
types, which have been fitted
by shipowners
to suit
particular vessels, trades and cargo
operations. In this chapter we will look at the
construction, opening/closing, stowage and
securing
devices together with some
advantages and disadvantages
of the
various basic types.
When
closed, hatch covers must repel green
seas and are often required to take heavy
loads, so they must be robust in
construction. However, they must not be rigid
when secured as they tend to move and shift
as the vessel hogs, sags and elastically
deforms in a seaway. They must also have a
sealing system and fittings to enable them to
be securely closed and battened down.
Other fittings may include gas sampling
points, locators, cleats, chains, safety
devices, stoppers, cement or grain loading
ports and ventilators (fitted to ballast holds
and OBOs).
There are two basic types of sealing system,
which are the double drainage system and
the 'Cat' system. The Cat sealing system
was originally used on Kvaerner hatch
covers and incorporates a half round edged
seal that acts down on to the flat coaming
bar. The more popular double drainage
Hatch Cover Types
sealing system has a rubber seal housed in
the hatch cover edges around the perimeter
acting
on to the upper edge of a
vertical
steel plate known as the compression bar.
All hatch covers should have some form of
drainage to remove slack water from the
covers and around the coaming bars and to
prevent the possibility of water entering the
hold and damaging the cargo. Drains from
the coaming bars are usually fitted at the
after corners, with non-return valves/traps.
Cross joints should also be capable of being
drained quickly and will often drain from the
side
of the cross joint
channel into the
external drain channel and then onto the
open deck.
Hatch covers must also have an operating
system that will enable them to be opened
and closed quickly and efficiently to save
downtime. They may be opened by means
of chains, wires, rack and pinion,
hydraulic
rams/hinges or by other hydraulic link
mechanisms.
Double skin or 'box section' hatch covers
were developed to span large openings.
They provide equivalent strength to those
with open construction, without protruding
far down into the cargo spaces and taking
up valuable cargo carrying and freight
earning capacity. Tween deck hatch covers
need to be even stronger as they may need
to take the additional weight of cargo laden
fork-lift trucks. The single skin type may be
considered to be a set of longitudinal and
transverse stiffeners with a top cover, side
and end panels. Tween deck covers can be
of the sliding type, pontoon, wire pull folding
or hydraulically folding box type.
All weather deck hatch covers are carried on
hatch coamings of varying heights,
depending on the type of vessel and
cargoes carried. The edge
of the hatch
cover
panels sit on the hatch coaming bar,
which carries the weight
of the covers when
secured and the cover
wheels when
opening/closing. The hatch cover sealing
27

32. Hatch Covers -Operation, Testing and Maintenance
mechanism is usually incorporated into the
outer edges
of the cover
panels, acting on
the coaming bar or a compression bar. The
hatch covers are generally secured to the
hatch coaming
by
cleats of various designs.
Hatch covers are usually less rigid than the
coamings and, as the ship flexes in a
seaway, some water ingress can occur,
causing weathertightness problems.
Weathertightness is not achieved by the
hatch cover rubber seal or packing and
compression bar alone. It is the combined
action
of
all the parts, ie hatch cover
side/end panels, outer drain channel, seal
and compression bar, inner drain channel
and non-return drain valves, which achieve
the watertight seal.
Hatch covers, which are fitted over holds
that may be ballasted, are required to be
additionally stiffened to take the sloshing
forces imposed by the ballast water carried
in the hold at sea. The covers or coamings
will also be fitted with large ventilators (see
Figure
5.1 ).
28
Figure 5.1
-Ventilators Fitted to Ballast
Hold Forward Coaming
5.1 Pontoon and
Tarpaulin Covers
These are still found on some older, smaller,
bulk and timber carriers. A number of full
width steel pontoons are fitted across and
within the hatch opening, loosely butting-up
against each other with no mechanical seal.
Tarpaulins then cover the pontoons, usually
three layers, which are in turn held in
position at the sides and ends by means of
batten bars (to stop the tarpaulins ripping in
the wind), which are held in place by
wooden wedges against steel wedge cleats.
The pontoons are usually of the all welded,
steel box type. Four lifting pockets are
situated at each corner to enable lifting,
using hooked wire strops, by crane or
derrick. ·
-t ') C ,...I' ,.., I .&.
There is no mechanical sealing system fitted
with this type
of hatch cover. The hatches
and
holds are maintained in a weathertight
condition by means
of the
tarpaulins fitted
over the pontoons. These are secured at the
sides and end by batten bars and wedges
(see Figure 5.2). The tarpaulin is folded over
at the edges then lengths of batten bar are
laid along the sides and end coamings
Figure 5.2 -Typical Pontoon and Tarpaulin
Hatch Covers

33. Lifting
pocket
Lifting
eye
pontoon
Tarpaulins
Hatch Pontoon
Sealing
Arrangement
Batten
bar
Wooden
wedg
es
Coaming
stay
deck
Figure 5.3 -Pontoon and Tarpaulin Sealing
System (cargo nets not shown)
against the tarpaulin edge. The hard wood
wedges are then hammered into position
against the angled cleats to hold the batten
bars
in
place.
A 'l ~01"' -1 r' I;'°'"" C°"
There are no cleats fitted to the coamings or
covers. Pontoons rely on their weight .and
location within the coaming plate to prevent
them from shifting: The tarpaulin covers are
held in position at the sides and ends by
batten bars held in place by wooden wedges
against steel wedge cleats. Heavy seas and
wind can lift tarpaulins at their edges if they
are not properly secured. Tarpaulins are
prevented from lifting by nets and ropes
Figure 5.4 -Pontoon and Tarpaulin Hatch
Coaming and Securing
Hatch Cover Types
across the top that are secured to coaming
stay hooks or rings.
A " (""\...,.,......,.;...,.,.../,..I,...,..,...,.,..
Before pontoons can be removed the nets,
wedges and battens must be removed. The
tarpaulins are then folded and stowed.
Removing the tarpaulins exposes the
pontoons, which can then
be
lifted by derrick
or crane
using hooks
in the four
lifting
pockets.
When closing, the pontoons are positioned
transversely within the coaming. Three
tarpaulins are spread over the complete
hatch opening, folded at their sides to take
the batten bars and wedges. Nets and ropes
are then fitted.
r A t::: ... ,....,., ....... ---f n.,.,.r---•-
Pontoons and tarpaulins are usually stacked
on top of each other on the main deck on
either side of the hatches.
Figure 5.5 - Stowage of Pontoons,
Tarpaulins and Nets
29

34. Hatch Covers -Operation, Testing and Maintenance
~ 1 ~ r.nmm,::lntc::.
Pontoons must be stowed on top of each
other or
on the main deck during
loading
and discharging, creating deck clutter
the system needs several crew to fold
tarpaulins, remove wedges and battens
and to hook up the pontoons for lifting
opening and closing take up valuable
time
there
is an inherent danger from swinging
pontoons around the main deck tarpaulins can be damaged by logs and
timber, increasing the risk
of water
ingress to the
holds.
When inspecting this type of hatch cover the
following should be reported on:
Wedge cleats -report any heavily
corroded or wasted cleats to be replaced
side and end battens -report any heavily
deformed/buckled battens that will need
to be faired
pontoons -report on condition,
particularly any corners sticking up that
might damage tarpaulins
condition and number of spare tarpaulins.
All hatches have three tarpaulins in use,
one
in 'new' condition and each
large
enough to cover the hatch
locking devices must be in position and
properly secured.
coamings with excessive wastage that
are near locking devices
the supply of spare hardwood wedges
the condition
of the coaming and
coaming
bar.
5.2 Direct
Pull Covers
These can be found in general cargo vessels
and smaller bulk carriers. Multi-panel covers
may· be operated by a wire, ie single pull as
shown
in Figure 5.6, activated by the ship's
gear,
usually by deck cranes or winches.
Alternatively, they may be pulled open or
closed by means of chains either side, the
McGregor Rolling Hatchcovers
Figure 5.6 -Typical Wire Operated Single Pull Hatch Covers
30

35. Figure 5.7 -Single Pull Hatch Cover
Coaming, Stays, Chains and Rollers.
chains being operated by hydraulic or
electric windlasses at the forward or after
end
of the hatch coaming.
ri -t l""cnc-+r• .,...:,.,.
Direct pull covers are single skin, flat steel
top and fabricated from all welded steel
panels. Bulk carriers may have domed
panels. These sides and ends will also be
Hatch cover
Double drainage
channel
Hatch Cover Types
welded steel panels. The covers are
strengthened by thick and deep
longitudinals, providing longitudinal strength,
with transverse floors of smaller scantlings
to provide rigidity and the ability to take
loads on top.
Panels are independent of each other when
lifted as they are only connected by the link
chains at each side. Lugs are provided
around the hatch cover sides (to take quick
acting cleats). Lugs are also provided at
each cross joint edge to house steel cross
joint wedge cleats (see Figure 5.10).
') ') Sea•: .... ,... ""ste-
This type of hatch cover generally uses the
double drainage system shown in Figure
5.8, which has external and internal drain
channels. In the diagram shown, the hatch
cover weight
is taken by the edges sitting on
the coaming
bar. This system incorporates a
rubber
seal, retained in the seal channel
around the hatch cover edges, that presses
against the top edge
of a
vertical steel
Non-return
drain trap
Weight
taken by
hatchcover edge
Figure 5.8 -
Double Drainage Sealing System
31

36. Hatch Covers -Operation, Testing and Maintenance
compression bar. This is the most important
barrier to water ingress and must be
retained
in an
elastic state to accommodate
hatch cover movement due to the flexing of
the ship. The rubber seal is made from a
specific type
of rubber with a specific design
compression that
is sufficient to maintain
watertightness without
permanently
deforming the rubber. Excessive
compression will result in the rubber 'setting'
or hardening, forming a deep permanent
channel and leading to less flexibility and
loss of compression. The steel to steel
bearing pads, or hatch cover edge, is
designed to take the load of the hatch cover,
not the rubber seal.
Any water that might pass the hatch cover
edge has to pass the rubber seal. Once past
the rubber seal it will pass into the inner
drain channel. As ships are generally
trimmed by the stern, the water runs down to
the after end
of the hatch coaming. A non­
return drain trap
is
usually fitted at each of
the coaming bar after corners, allowing any
water
in the drain
channel to drain down to
the deck.
Hatch covers are held in position by quick
acting cleats around the sides and ends,
with steel wedge cleats spaced out across
the top
of each cross joint (see Figures 5.9
and
5.10). These retain the covers in place
but allow a certain amount of movement
relative to the coaming bar. Their main role is
to keep the hatch covers
in
place while at
Compression
bar
Figure 5.9 -Quick Acting Cleats
32

37. Hatch Cover Types
C/J = Cross Joint F
P
II pr: n n 1111 n
I I
(Centre face seal here)
C/J
Compression Rubber
bar seal
~
-,
t...---...._J
C/J
C/J
Cross
Joint Face Seal Detail
A
Figure 5.10 -Plan View of Direct Pull Hatch Cover with Fittings
sea. They prevent the covers from lifting
when the ship's hull flexes in a seaway.
Two quick acting cleats are fitted to either
side of each panel, with those at the forward
and after ends distributed equally across the
width of the panel. The side and end cleats
pull the hatch cover panels down onto the
seals and bearing pads. The cross joint
cleats ensure that adjacent panels match up
so that the cross joint seals are compressed.
Adjacent panel surfaces should be even, ie
with no overlap, when cross joints have been
cleated. If the cross joint face seal is
horizontal then the right hand covers should
be lowered into position first so that the left
hand panel compression bar is dropped
down
on to the
seal when the panel is
lowered.
Cleats should not be over tightened as this
may cause damage to the rubber cleat
washer, which can become hardened and
rigid, not allowing the cover to flex. If bearing
pads are also worn, over-tightening of cleats
will cause excessive grooving of the seals.
Over-tightening of cross joint cleats may
result in other cross joints being pulled
apart, allowing water ingress.
33

38. Hatch Covers -Operation, Testing and Maintenance
Hatch cover
Rubber seal
Bearings pads ~
Weight taken/ ~~ ........ .___.._.~...-....-....u
by bearing pads
Quick acting cleat
Coaming
Compression bar
Figure 5.11 -
Double Drainage System Showing Quick Acting Cleat and Internal Bearing Pads.
In Figure 5.11, the weight of the hatch cover
is taken
by the bearing pads, which are generally around 450 mm in length and
spaced at appropriate locations along the
length of the coaming bar. The bearing pads
also act as spacers, ensuring that the rubber
seals are only slightly compressed. As may
be seen, if the bearing pads are allowed to
corrode and wear down, more pressure
is applied to the rubber seals. This causes
them to become heavily grooved and
hardened, which eventually allows water to
f-----Lever
Quick
'---___ acting cleat
i--Wheel bar
Compression
'----:.__'--"'.z__ __ bar
Steel/steel
'------_.:_ ___ bearing pad
Figure 5.12 -MacGregor Flexseal System
34

39. pass between the compression bar and seal.
If the bearing pads are not renewed,
renewal of the rubber seals is pointless as
they will continue to become heavily
grooved.
MacGregor have introduced the Flexseal
system (see Figure 5.12), which
incorporates a special hollow rubber seal.
This is reported to reduce the possibility of
heavy grooving of seals.
'"" A f"'\...,.,..,....,.;...,.,.../"l'"'"inn
All quick acting side cleats and cross joint
cleats must be released to allow the cover
panels to be raised. Each panel is fitted with
two wheels each side to enable the panels
to roll forward or aft. The wheels are of a
specific type, working
on the eccentric principle. The outer part of the wheel is on
Hatch cover
Roller
Hatch cover Panel Lowered
Hatch Cover Types
an eccentric so that, when turned by a small
crow bar, the wheel can be turned through
180 degrees to raise the hatch cover and
vice versa for lowering (see Figure 5.13). A
locking pin prevents the wheel from
returning to the lowered position.
With the direct pull, chain operated, type
each
of the
panels has only one roller wheel
at its forward end, with the after end resting
on the adjacent cover panel. The wheels are
on fixed shafts, unlike the single pull wire
operated type. Consequently, the coaming
bar channel in way of the rollers must be
lifted to allow opening of the hatch covers.
This is carried out
by
individual hydraulic
track lifting jacks or by a link rod that
operates each roller lift pad simultaneously,
the rod being operated by a single hydraulic
jack at the forward or after end of the side
Hatch cover
Hatch cover Panel Raised
Figure 5.13 -Diagram Showing Direct Pull Hatch Cover Rollers
35

40. Hatch Covers -Operation, Testing and Maintenance
Cross joint cleat
~
Junction piece assembly
Eccentric wheel turning lever
Eccentric wheel locking,pin
Eccentric wheel
Figure 5.14 -Diagram Showing Direct Pull Hatch Cover Rollers, Fittings and Hydraulic Lifting Jack.
Figure 5.15 -Direct Pull Hatch Covers Operated by Side Chains
coaming. Once raised, the link rod is fixed in
position by a locking pin (see Figure 5.14).
Chains run along the side of the hatch
covers
in
steel angle bar channels to a
hydraulic windlass, and back again to the
forward-most hatch cover
in the system (see
Figure 5.15). The
hydraulic windlass drives
the chains
on each side of the covers at the
36
same speed. Connected at corresponding
points
on the side chains are
elongated
washers, which are connected to the side of
the last hatch cover panel. When operated,
the chains pull this hatch cover, which in turn
pushes those ahead
of it to the stowage well.

41. Hatch Cover Types
Wire to winch or crane hook
Electronic
wheel
Balancing
roller
Cleats I
Hatch coaming
stay
Coaming
bar
Figure 5.16 -Direct Wire Pull Hatch Cover Opening and Closing Arrangement
As the first panel moves towards the
stowage area, side wheels at the centre of
each side panel (slightly higher than side
rolling wheels) meet with a vertical side plate
that accommodates the side roller. As the
panel and roller move along the plate, the
panel tilts to the vertical and then rolls into
the stowage well. Due to the chains linking
the adjacent panels, each of the other
panels follow until all are stowed in the well.
Closing the covers is the reverse of the
previous procedure except that when
opening the panels push each other and
when closing the side chains pull adjacent
covers along the coaming to the stowage
well.
With the single pull wire operated system,
the procedure is much the same except that
instead
of
windlass operated side chains
pulling the covers, a wire from a deck crane
wire
is connected to an eye on the
leading
panel, which is then pulled with the other
panels following (see Figure 5.16). The side
chains maintain the alignment of the panels
as they roll into the stowage well.
5 " c:. S""'
.& -....... ,...1e-
On smaller ships all of the panels may roll
into a well at the forward or after end of the
coaming, depending on space available and
the working trim
of the
vessel. On larger
hatches, some panels will stow forward and
some aft, with a cross joint where the covers
meet each other when closed. Rubber
stoppers prevent the stowed panels from
running
away.
Fig 5.17 -Domed Direct
Pull Hatchcovers
and Stowage
37

42. Hatch Covers -Operation, Testing and Maintenance
The more panels there are, the higher the
maintenance required, and this
is the case
with this type
of hatch cover. The
lead panel
has six wheels, three each side, and other
panels have two each side, all of which need
to
be
regularly greased. Cleats need to be
regularly adjusted and chains need
occasional length adjusting as the links tend
to wear
and stretch with operation. The panels are not linked by steel hinges and are
independent
of each other except for chains. Consequently, chain lengths are critical with
this design as the panels must be perfectly
aligned when lowered onto the compression
bars. Several crew are needed to release
side and cross joint cleats and to lift the
hatch cover wheels for opening and lowering
when closing.
The single wire pull type needs more deck
crew, one to operate the crane and another
two to attach the wire to the hatch cover
panels. While the chain operated pull type
does not need
as many deck crew, there are
more chain
rollers that need greasing and
chains that need occasional adjusting.
There
is a
steel-to-steel contact between the
panel rollers and the coaming bar. There is
no point in either being painted as the
coating will soon wear off with operation of
the panels. This fact, in combination with the
inhospitable environment in which the
covers operate, means that corrosion and
wastage
is
accelerated. The wheels and
coaming bar erode and wear down, reducing
clearances.
Link chains are, by their very nature, elastic
enough to take the shock loads of opening
and closing hatch cover panels. However, if
wheels are not regularly greased this will
place additional loads on the chains, which
will tend to stretch causing misalignment of
the panels.
In older designs without bearing pads, the
edge
of the hatch cover resting on the
coaming bar can cause fretting, grooving
38
and abrasion damage to the coaming bar.
In
turn this can cause the hatch covers to drop
further onto the coamir:ig bar, causing heavy
grooving and hardening
of the rubber
seals.
When inspecting this type of hatch cover the
following should be reported on:
Seals -report if heavily grooved,
hardened, damaged or missing
watertightness test results
hatch wheels greased and free
condition
of chains and wires
condition
of
wheels, tracks and any jacks
condition
of drains and non return
assemblies
the tightness and condition of cross joint
wedges and side cleats
the condition of the coaming ,;3nd
coaming bar
the condition
of the
panels, edges, etc.
Figure 5.18 -Wire Operated Folding
Tweendeck Hatch Covers. (these must be
lowered before proceeding to sea as they
are not designed to remain in the open
position)
5.3
Folding Covers
These will be either hydraulic or wire
operated and may be fitted to weather deck
and tweendeck hatchways. The covers may
be
of
flat topped panels, box or single skin
design.
,_
:::::
s
a:
e

43. Folding covers are increasingly being fitted
for both weather
and tween deck use
in
general cargo and multi-purpose vessels.
This design has been developed into various
other designs including:
Foldtite hydraulic folding
' link-link hydraulic folding
hydraulic ram operated
hydraulic hinge operated.
An example is shown below.
Figure 5.19 -Folding Hatch Cover Single
Skin Construction
r-~ A r',-. ...... ~.i.~
Folding covers have a flat steel top and are
fabricated from all welded steel panels.
Sides, ends, and in the case of box type
bottom panels, are also of welded steel
panels. They are strengthened by thick and
deep longitudinals that provide longitudinal
strength, with transverse floors of smaller
scantlings to provide rigidity and with the
ability to take loads on top. As ships using
this type
of hatch cover become
larger and
hatches wider, the panels become heavier.
To keep weight to manageable levels the
length of panels is reduced so that there are
Hatch Cover Types
more folding panels. The first set of panels
to fold open, adjacent to the coaming end,
are termed the leading pair: The following
pair is termed the trailing pair: Multiple
trailing pairs are termed first, second, etc,
trailing pairs.
Figure 5.20 -Folding Hatch Cover Wheel
Figure 5.21 -Folding Hatch Cover Cleat.
5 ,..., ,..., l"'0aP ...... ,.. l"'yl"'+em
This type of hatch cover incorporates the
double drainage sealing system. As the
hatch cover starts
to open, the
leading
wheel rides up an incline on to the raised
wheel track, keeping the seals clear of the
coaming
bar. The reverse
applies during
closing (see Figure 5.20).
39

44. Hatch Covers -Operation, Testing and Maintenance
Rubber washers
Coaming
Wedge Cleat Shoe Cleat
Figure 5.22.-Wedge and Shoe Cleats
Panel Raised Panel Cleated
Figure 5.23 -Hydraulically Operated Hook
Cleats
Ill""' ~
This type of hatch cover tends to have larger
quick acting cleats, although some very
large covers may have set screw type side
cleats, which need a spanner or wrench to
tighten
in to position.
Cleats are prevented
from being over tightened and placing undue
pressure
on the rubber
seals by the bearing
pads. Because they are connected by steel
hinges, there is no need for cross joint
cleats. As they close, the two faces of the
adjacent panels come together, one with a
compression bar the other with a matching
rubber seal, to form the watertight cross joint
seal
The folding hatch cover may be secured in
place by means of automatic wedge or shoe
40
cleats, as shown in Figure 5.22. As the
panels lower into position, the wedges,
welded to the coaming bar, locate in
matching lugs welded on to the hatch cover
side, the wedge action forcing the hatch
cover panel down on to the compression bar.
. ,../""I""". ,....
Wheels are fitted to the ends and sides of
the last panel and at the junction of pairs of
panels, so that the hatch covers roll into
position along the coaming bar: Earlier
designs were wire operated, using a deck
crane or electric/hydraulic windlass to pull
the wire to open the hatch cover: The wire is
connected to a shackle at the centre of the
cross joint
on top of the first
panels or
'leading pair' and the arrangement will
depend on the number of panels. With four
~anels, the leading pair will be pulled open
first, the trailing pair rolling behind on the
coaming
bar. The wire is then secured to the trailing pair at the centre of the cross joint
and the trailing pair pulled up for stowage.
With more than four panels, four panels are
opened to the forward end and the rest to
the after end.
With the development of hydraulics came
the hydraulic ram operated folding hatch
cover. Rams may be positioned in various

45. Figure 5.24 -Hatch Cover Hydraulic Rams
Foldtite
~~ Intermediate hinge
External liydraulic
cylinder for leading
pair
t.t~ Trailing
pair
Lifting wheel
for trailing
pair
Bell crank
~4 1!!1'1J Longitudinal
fixing
device
External hydraulic
cylinder for bell
crank
Figure 5.25 -
Hydraulic Ram Operated
Foldtite System
Hatch Cover Types
locations to enable opening. The first type
incorporated the rams at the forward and
after ends
of the coaming, operating
only
two panels each, one pair folding aft and the
other pair forward (see Fig 5.24). The rams
were positioned so that they would push up
the leading panel, one end being hinged to
the main deck, the second panel being
linked to the first by hinges and following
automatically.
For vessels with a lack of deck space,
hydraulic rams at either end took up
considerable space. An extension of the
hydraulic ram operated hatch cover is the
Foldtite design with rams at each side of the
covers (see Figure 5.25).
Another variation
on the
hydraulic folding
hatch cover is the space saving link-link
hydraulic folding hatch cover, which
incorporates hydraulic rams in the panel's
operating hinges that open and close the
covers (see Figure 5.26).
Link-Link
Hydraulic Folding
End hinge
Figure 5.26 -Hydraulic Link Operated
41

46. Hatch Covers -Operation, Testing and Maintenance
Figure 5.27. Hydraulic Hinge
The next progression was the fitting of
hydraulic hinges to each of the pairs of
panels. This removed the need for space for
hydraulic rams at the ends or sides (see
Figure 5.27).
42
Figure 5.28 -Stowed
Folding Hatch Cover
Locking Devices
Panels fold vertically and will be stowed at
the forward end
of the hatch coaming as
shown
in Figures 5.29 and
5.30 . Once
opened, the covers are locked together at
the side and bottom
by
steel hooks on to
matching lugs on adjacent panels. These
are generally locked in place by locking pins
to prevent inadvertent release. Wires can
then be removed and cargo operations
commenced. There may also be a back up
locking device in the form of a bottle screw
and wire strop, secured to the coaming
structure and connected to the leading panel
as shown in Figure 5.28.
As with the direct pull type, the more panels
you have the higher the maintenance, and
this is the case with this type
of hatch cover.
However, the box
sectiorJs are easier to
maintain with fewer wheels requiring regular
greasing and fewer cleats needing adjusting.
There are also no chains fitted. The panels
are linked by steel hinges, which also need
regular greasing. Grease points are supplied
at a convenient position with grease
supplied by pipes to the relevant point. The
advantage
of this type of hatch cover is that,
once
cleats have been released, fewer crew
are required.
There
is a
steel-to-steel contact between the
rollers and the coaming bar. There is no
point
in either being painted as the coating will soon wear off with operation of the
panels. This fact, in combination with the
inhospitable environment in which the
covers operate, means that corrosion and
wastage
is
accelerated. Wheels and
coaming bar will erode and wear down,
reducing clearances. Liberal application of
grease is therefore advisable.
Wire operated folding hatch covers can be
considered as inherently dangerous. If the
wire was to part, the hatch cover panels
would crash down onto the coaming and
possibly into the hold. However, the same

47. can happen if the hydraulics are lost from
hydraulically operated covers.
Opening and stowing covers will cause the
vessel's centre of gravity to be raised.
Therefore, the vessel should have an
adequate GM before the covers are opened.
Opening
in high winds can
also cause a
windage and stability problem for smaller
vessels.
With the gradual scrapping of older tonnage
that
is fitted with direct
pull hatch covers and
wire pulled folding hatch covers,
hydraulically folding hatch covers will be in
the majority.
When inspecting this type
of hatch cover the
following should be reported on:
Seals -report if heavily grooved
hardened, damaged or missing
watertightness test results
hatch wheels greased and free
condition
of
hydraulic pipes -report if
leaking or wasted
condition
of rams and track jacks
condition
of drains and non-return
assemblies
the tightness and condition of side cleats
the condition of the coaming and
coaming bar
the condition
of the
panels, hinges, etc.
i::. 'l 7 n ......... ·
Hatch cover manufacturers are continually
striving to improve their designs to improve
ease
of operation and to reduce the amount
of required maintenance. The
latest
MacGregor hydraulic folding designs are
shown
in Figure 5.29 and
5.30.
When carrying out condition surveys of
older vessels it may often be found that the
hull and machinery are generally in
satisfactory to good condition. It is often the
hatch covers that pull the standard of the
Hatch Cover Types
Intermediate hinge ___ _
Longitudinal stopper
Wheel -----,
--~LJ
Figure 5.29 -MacGregor Two Panel Folding
Hatch Cover
(Courtesy of MacGregor Group)
Intermediate hinge ..i
Leading pair _____ _
Figure 5.30 -MacGregor Multi-Folding
Hatch Cover
(Courtesy of MacGregor Group)
43

48. Hatch Covers -Operation, Testing and Maintenance
Figure
5.31 -
Bell Crank Hydraulic
Ram System
(Courtesy of MacGregor Group)
vessel down. The main areas that cause
problems are the compression bar, coaming
bar, bearing pads and rubber seals. All four
of these areas must be in good condition to
give the hatch covers a chance of being
watertight.
The correct height
of the bearing pads
will
ensure that the correct pressure is applied
to the rubber seals. In the case of hatch
covers where the edge
of the cover takes
the
load, the coaming bar condition will
determine the load on the seals. Due to the
exposed environment
in which ships
operate, the combination
of seawater,
together with the ship's motion with
resultant
chafing, can cause accelerated
corrosion/erosion of the bearing pads or
coaming bars. Regular greasing of the
bearing pads helps retard the rate of
corrosion and erosion. Internal bearing pads
have a clear advantage over external pads.
However, they are still subject to chafing and
need regular greasing.
MacGregor have identified these
problematic areas and are attempting to
reduce the detrimental effects with new and
innovative designs. These include the
Flexseal, Flexipad, Lubripad, Polypad and
steel bearing pad shown in Figures 5.32 to
5.39.
44
Figure 5.32 -The
Flexipad Bearing Pad
(Courtesy of MacGregor Group)
Figure 5.33 -The Lubripad Bearing Pad
(Courtesy of MacGregor Group)
Figure 5.34 -The Polypad Bearing Pad
(Courtesy of MacGregor Group)
Figure 5.35 -The Steel Bearing Pad
(Courtesy of MacGregor Group)

49. iii' Lever
Quick
I B acting cleat
Compression
~,. ~:'/i"" bar
Steel/steel
~------'-----bearing pad
Figure 5.36 -The Flexseal System With
Internal Steel-to-Steel Bearing Pads
(Courtesy of MacGregor Group)
bearing pad
Quick acting
I cleat
Lever '-
Figure 5.37 -The Flexseal System with
External Steel-to-Steel Bearing Pads
(Courtesy of MacGregor Group)
Lever _____ -.-_..,
Quick acting
cleat ,_..
Stainless steel
tightening
surface---,
J
Figure 5.38 -The Cat System With
External Flexipad
(Courtesy of MacGregor Group)
Hatch Cover Types
Figure 5.39 -The Cat System With
External Lubripad
(Courtesy of MacGregor Group)
The advantage of these designs is that the
pads can be renewed relatively easily
compared to traditional steel-to-steel bearing
pads. They can also be 'shimmed' to
maintain the pad at the correct height.
Rubber seals have a tendency to harden
over time and should be replaced every five
years or when heavily grooved, whichever
comes first. The introduction
of the
Flexseal
system is intended to reduce the possibility
of heavy grooving of seals, by using a
hollow rubber seal. Variations in the design
of rubber seals may also be found in the
market as shown
in Figure 5.36 and 5.37.
The Cat
profile seal has also been
introduced with hydraulic folding hatch
covers.
A key requirement with the Cat system
is
that the
seal should act downwards onto a
smooth clean surface. Unfortunately,
coaming bars tend to be dirty and often
corroded, reducing the effectiveness of the
seal.
As may be seen from Figures 5.38 and 5.39,
MacGregor have introduced a stainless steel
strip that is fitted along the coaming bar
where the Cat seal acts downwards, the aim
being to maintain the coaming bar
in a
smooth condition. However, crew are
still
45

50. Hatch Covers -Operation, Testing and Maintenance
required to keep the coaming bar free of
debris and dirt when closing the covers.
MacGregor have also introduced more
variety
in the cross joint
sealing systems.
Two of these are the Omega and Swing-seal
systems.
Note the cam system shown
in Figure 5.41,
which
allows adjustment of seal pressure.
46
Figure 5.40 -The Omega Cross Joint
System
(Courtesy of MacGregor Group)
Figure 5.41 -The
Swing-Seal Cross
Joint System
(Courtesy of MacGregor Group)
Figure 5.41 b -An
Alternative Rubber Seal
Design

51. Hatch Cover Types
Figure 5.42 -Rolltite Hatch Cover System
5.4 Roll Stowing Covers
Fitted to general cargo vessels and small to
medium bulk carrier weather decks.
Space on deck is often limited, making the
stowing
of hatch cover
panels a problem. It
is debatable whether the Rolltite covers have
solved this problem. Hatch cover panels roll
onto a drum for stowage, as shown in Figure
5.42. The hatch cover consists
of a number
of
panels spanning the hatchway, which are
hinged at each of the cross joints. This type
is also popular on small general cargo
vessels and inland waterway vessels.
c ii '1 ("',..,.,..,.l' ....
Roll stowing covers are full width, single
skin, flat steel top and fabricated from all
47

52. Hatch Covers -Operation, Testing and Maintenance
welded steel panels. The sides and ends are
also of welded steel panels. They are
strengthened
by thick and deep
longitudinals
providing longitudinal strength, with
transverse floors of small scantlings to
provide rigidity with the ability to take loads
on top. The cover panels are linked by steel
hinges that allow the panels to only fold
through 180°, preventers stopping the
~a~~ls from bending backwards, giving them
ng1d1ty when lifted. There is only one wheel
fitted to the port and starboard sides of the
last panel, allowing the panels to roll and
stow.
Seal with hatch shut
This type
of
~atch cover tends to have a
neoprene packing material retained in a seal
ch~nnel around the edges of the panels,
~h1~h presses down on to the flat coaming
s1m1lar to the Cat system shown in
Figure 5.43. As the ingress of water is
prevented
by the rubber
seal alone, the
hatch coaming bar must be clean and
smooth to create a good seal.
Seal with hatch open
·~
--------
Fig 5.43 -Cat Sealing System
48

53. Hatch Cover Types
Fig 5.44 -Hatch Cover Cat Face Seal
~ A ') C' ....
,.J 8" .: """"'
This type of hatch ~over tends to have larger
quick acting cleats. Cleats are prevented
from being over tightened and placing undue
pressure
on the rubber
seals by the bearing
pads. Being connected by steel hinges there
is no need for cross joint cleats. As they
close, the two faces of adjacent panels
come together, one with a compression bar
the other with a matching rubber seal, to
form the watertight cross joint seal.
A A r'\-,..... '
The leading wheel is lifted by a hydraulic
jack lifting the relevant section of track,
which
in turn
results in all panels clearing
the coaming bar. The stowing windlass is
then operated to roll the covers onto a drum
(see Figure 5.42).
Figure 5.45 -
Side Sliding Hatch Covers on
a Capesize Bulk Carrier
,... t::. Ctn·. ·-g,--.& o-ne'S
As may be seen from Figure 5.42,
the panels are rolled onto a drum at the
forward end
of the hatch by
hydraulic or
electric motors. In order to stow correctly, the
first panels to roll on to the drum are shorter
in length, with the latter panels being longer.
49

54. Hatch Covers -Operation, Testing and Maintenance
It is debatable whether this system has any
speed or space saving advantages over
other types, as cleats have to be removed
and the wheels lifted in the same manner as
for folding hatch covers.
This is not a popularly adopted type of hatch
cover. In many years of marine surveying I
have seen only one such type, where the
crew reported that there were many
problems with the windlass system.
When inspecting this type
of hatch cover the
following should be reported on:
Seals -report if heavily grooved,
hardened, damaged or missing
watertightness test results
hatch wheels greased and free
condition
of
hydraulic pipes -report if
leaking or wasted
condition
of track jacks
condition
of drains and non return
assemblies
the tightness and condition of side cleats
the condition of the coaming and
coaming bar
the condition
of the
panels, hinges, etc.
5.5 Side and Rolling
Covers
50
Figure 5.46 -Side Rolling Hatch Cover Face
Compression Bar and Drain Channel
Generally fitted to large bulk carriers, 080
carriers and combination carriers. These
consist
of
two large panels at each
hatchway which open athwartships. They
are extremely heavy and require hydraulic
lifting to raise them into a rolling position.
The cover panels open sideways, the centre
joint being along the centre line of the
vessel.
+.. ,._+·
Side and rolling covers are generally single
skin but may also be box type, flat steel top,
fabricated from all welded steel panels. The
sides and ends are also of welded steel
panels. They will be strengthened by thick
and deep longitudinals providing longitudinal
strength with transverse floors of smaller
scantlings to provide rigidity.
Coamings are approximately 2 m high with
guides extending both sides so that panels
roll into open position on guides.
The weight
of the hatch covers may be
taken
by bearing pads or by direct contact of
the hatch cover edge with the coaming bar.
This type of hatch cover uses the
double
drainage system, with a compression bar
extending the full perimeter of the coaming
bar. The two panels come together with a
direct facing seal system there being a
compression bar on one cover and a
matching rubber seal on the other. A drain
channel is positioned beneath the seal,
which drains to the forward and aft coamings
on to the open deck. Non return drain traps
are also fitted on port and starboard, forward
and after ends.

55. Figure 5.47 -Side Rolling Cross Joint
Side Cleats
Figure 5.48 -Side Rolling Cross Joint
· Cleats
c::. c::. ') c,.,.,... ·~=-~ ...J
Hatch covers are held in position by large
quick acting cleats or set bolt cleats around
the sides and ends. Set bolt cleats may also
be spaced out across the top of each cross
joint (see Figure 5.48). Set bolt cleats may
also be fitted at the cross joint sides, which
may be vertical or horizontal across the joint
(see Figure 5.47).
Before the cover panels can be secured they
must be correctly aligned. A number of
different methods are used and examples
are shown in Figures 5.49 to 5.52.
The advantage of the arrangement shown
in
Figures 5.51 and 5.52 is
that'it locates the
cover panels both transversely and
longitudinally.
Hatch Cover Types
Figure 5.49 -Side Sliding Hatch Cover
Centre Locating Lugs
Figure 5.50 -Side Sliding Hatch Cover
Panel Locating Lug
Figure
5.51 -
Side Sliding Hatch Cover
Centre Locating Cups
51

56. Hatch Covers -Operation, Testing and Maintenance
Figure 5.52 -Side Sliding Hatch Cover
Panel Locating Cone
A f"'
,.,. . '""'"'
There are three methods employed to
operate side sliding hatch covers, rack and
pinion, chain and wire operated. However,
before the panels can be opened they must
be lifted. This is carried out by raising the
coaming track
in way of the cover
panel
rollers using hydraulic jacks, as shown in
Figures 5. 53 and 5.54.
52
Figure 5. 53 -Hydraulic Jack and Track in
Raised Position
Figure 5.54 -Hydraulic Jack in Lowered
Position
Figure 5.55 -Hydraulically Driven Rack
and Pinion Drive
(Courtesy of MacGregor Group)
Figure 5.55 shows the rack and pinion
system. The rack or gear
is turned by means
of a
hydraulic motor. This is engaged with a
toothed rack extending along the underside
and along the centre line of one of the hatch
covers. A wire and pulley system enables
the cover with the rack and pinion to operate
the other hatch cover (see figure 5.57).

57. Figure 5.56 -Chain Driven Side Sliding
Hatch Cover.
(Courtesy of MacGregor Group)
Figure 5.57 - Side Sliding Hatch Cover
Showing Chain Arrangement and
Hydraulic Jacks
(Courtesy of MacGregor Group)
The chain operated system is similar to the
rack and pinion system
in that the rack and
pinion are
replaced by a hydraulically driven
chain windlass, the chains operating both
hatch covers simultaneously via pulleys (see
Figure 5.56).
The wire operated system
is
similar to the
chain driven system, the hydraulic driven
chain windlass being replaced by wires that
operate both hatch covers simultaneously
via pulleys.
When closing side sliding hatch covers, the
covers should be brought together first and
the cross joint cleats secured to make the
two halves into a single hatch cover. The
covers should be lowered, then the end and
Hatch Cover Types
side cleats operated. Attempting to bring the
covers together with them lowered is almost
impossible as you are trying to pull two very
heavy steel units together along rubber
seals. It is therefore unlikely that the face
seals will be made properly, with the
possibility of misalignment of one or other of
the covers.
c:: c:: c:. C' "",...,. ...... ,... ,...,.~ .............. l'"'\1,,...
The two hatch covers when closed are equal
to half the vessel's beam. When opening,
the panels slide sideways and outboard,
their rollers travelling along tracks that
extend out to the sides
of the
vessel.
Locking devices are fitted to prevent the
cover panels from moving when opened.
These may be pins fitting into slots in the
cover panels and tracks or a similar device.
r:: c:: ~ r\,..,.,..: ........ ,.,!,.... ·-• ......... .....,.,...,....,.+
Until recently, the side sliding hatch cover
lifting, rolling and cleating actions have been
carried out separately. This necessitated
releasing the cleats, operating the hydraulic
jacks to lift the wheel bar and then pulling
the two covers apart using the wire/chain
windlass or rack and pinion drive.
MacGregor have developed the Roll-up-Roll
system that enables panel lifting, partial
rolling and cleating in the same action. The
system can be fitted with rack and pinion
drives or chain/wire operated types. The
system also adopts the auto-cleating
system.
Figure 5.58 -
Auto-Cleating System for
Roll-up-Roll Hatch Covers
53

58. Hatch Covers -Operation, Testing and Maintenance
Figure 5.59 -The Roll-up-Roll System in
Closed Position with Wheels Lowered
Figure 5.60 -The Roll-up-Roll System in
Opening Position
When closing, as may be seen from
Figure 5.59, the yellow cog segments
simultaneously lower and merge the two
panel faces together, while the cover panel
wheels drop into a locating gap in the
coaming
bar. As they do so, the
autocleats
come into effect.
When opening, as may be seen from
Figure 5.60, the hatch covers are lifted to the
rolling position by the hydraulically actuated
yellow cog segments. The cover panels are
simultaneously uncleated, lifted and rolled
outboard onto the wheel bar. The cover
panel drive mechanism would then be
activated, ie rack and pinion, chain or wire
systems.
54
With larger, heavier panels two hydraulic
rams are used. For
small panels, one
hydraulic ram.activating only one of the cogs
may be adopted.
Set bolt studs take a little longer to release.
Once the cleats have been released and the
track raised, hatch covers can be opened
and closed quickly, which is often necessary
with water sensitive cargoes when rain is
threatening. The design
is
relatively simple
with few moving parts needing maintenance.
As large bulk carriers may be allowed to
ballast one or two holds, large ventilators will
be fitted to the cover or coaming
of the ballast holds with additional stiffening of the
cover panels to take the loads exerted by
sloshing
of the
ballast water.
The rack and pinion system requires regular
grec;ising, as do all wires and pulleys with
wire operated covers. Wires will require
periodic re-tensioning to ensure correct
alignment of the two cover panels. Hydraulic
jacks may be covered in grease
impregnated sack cloth to protect them from
the elements.
When inspecting this type
of hatch cover the
following should
be reported on:
Seals -report if heavily grooved,
hardened, damaged or missing
watertightness test results
hatch wheels greased and free
condition of hydraulic pipes -report if
leaking or wasted
condition
of track jacks
condition
of drains and non return
assemblies
the tightness and condition of cross joint
and side cleats
the condition
of the coaming and
coaming bar
the condition
of the panels.

59. 8 •hr n_r._v-i.....ire
The bulk carrier Derbyshire sank in
September 1980 in the Pacific, about
350 miles south east of Japan. The sea is
about 4200 metres (2~ miles) deep at this
point, 44 people died, 42 crew and the wives
of two of the officers.
She was a very large OBO with a
deadweight
of
160,000 tons of oil, iron ore,
coal, grain or other bulk cargoes.
She was the biggest British registered
merchant ship ever to have been lost. 294
metres (1000 ft) long -almost three times
t
he
length of a football pitch and 44 metres
(150 ft) wide -as wide as a six lane
motorway. Her loaded draught was 18.5
metres (62 ft). She had one 30,400 hp diesel
engine driving a single propeller.
In the 1980s about 17 ships like the
Derbyshire were lost each
year. The figures
for the years
1993-2002 were 108 ships lost.
The loss
of the Derbyshire was
extraordinary because she was only four
years
old; she was British owned and
manned
by a competent and experienGed
Master and crew; she was
built by a British
shipyard -Swan Hunters; she was fully
classed A 1
by Lloyds Register of Shipping;
all her surveys and certificates were up to
date. On her final voyage, she left Fos sur Mer,
France on 23rd June 1980 for New York.
She arrived on 5th July to take on fuel oil
bunkers. She got to her loading port, Sept
Isles, Canada on 10 July and left on 11th
July after loading 157,447 tonnes of iron ore
concentrates bound for Japan.
She sailed for Japan via Capetown, where
she took
on stores. After
leaving Cape Town
t
he charter party required the ship to
comply
with recommendations from a weather
routing organisation called 'Ocean routes'. It
would advise on course and speed,
according to expected weather conditions, to
minimise fuel consumption. The ship sent
Hatch Cover Types
messages to Oceanroutes every two days,
giving her position and speed.
On 3rd
September the Master increased the ship's
speed to 12.5 knots to pass ahead
of a
tropical depression, which he had learnt
about from a Japanese weather fax.
Oceanroutes confirmed the existence of the
tropical depression and recommended that
the ship take a northerly course to clear it.
On 5th September Oceanroutes told the
Master that his route was still valid and that
the tropical depression would reach storm
intensity by the following
day.
On 6th
September the ship reduced
speed to
10
knots as the tropical depression had
apparently subsided, but during the course
of that day typhoon Orchid
developed close
to the tropical depression. Some 20 years
later Oceanroutes was criticised for not
warning the ship about Orchid.
The Derbyshire's last message was to her
owners on 9 September 1980 it read.
"9th September 0930 GMT; Now hove to
due to severe tropical storm; estimated
time
of arrival Kawasaki 14th
hopefully"
This was the last known message sent by
the ship, No MAYDAY (distress message)
was heard, which is most unusual.
On 13th September 1980 the shipowner
asked the Japanese authorities to search for
the Derbyshire. On 15th September the
Japanese authorities and other ships
in the
area commenced searching. An
oil slick was
found and a sample was sent ashore for
analysis. This showed that the oil was of the
same type as that used
by the Derbyshire.
The search was interrupted
on 17th
September due to another typhoon.
It
resumed on 18th September but was called
off on 21st September as nothing had been
found.
The UK Government refused to hold a
formal investigation because there was no
evidence, so
an investigation
would be
unable to find out why she had disappeared.
55

60. Hatch Covers -Operation, Testing and Maintenance
The Department of Transport instead asked
two independent bodies to undertake some
research into bulk carrier losses.
In March 1982 one of the Derbyshire's sister
ships, the
Tyne Bridge, encountered severe
weather
in the North Sea and her deck
plating started to crack just forward of the
bridge
in an area known as Frame 65. Ships'
frames are numbered from aft and the
Derbyshire had over
300 frames. It was
found that the damage was caused by a
defect
in the Frame 65 area. The four other
remaining sister ships were contacted. Each
one
in turn found
similar damage in the
same location.
It was later found that the last five of the six
sister ships, including the Derbyshire, had
been modified
in this area and that the
shipyard had
mislaid the plans of the
modification. The modification resulted in a
massive longitudinal girder being cut at the
bulkhead by Frame 65 -instead of
penetrating the bulkhead to maintain
strength. The modification sought to
maintain longitudinal strength by means of a
fore and aft bulkhead. Not only was this
much weaker than the massive girder but
was out
of
line with the bulkhead by as
much as 35 mm (1.5 inches). This
modification was the result of a change in
International Rules for ship construction -
and was not done at random by the
shipyard. However, even though the first
sister ship, the Furness Bridge, had been
built to plan she also suffered cracks in the
same area.
Peter Ridyard, the father of the 4th Engineer
Officer on the Derbyshire was a very
experienced ship surveyor. He was
convinced that a ship like the Derbyshire
should not have sunk and he started to
collect information about the damage to her
sister ships
in the Frame 65 area. He sent
this data to the Department
of Transport
(DOT) in September 1982 but received no
response. He sent it again
in June 1983 but
once again no response.
56
In July 1985 the DOT issued a draft report
based, presumably, on the research done by
the two independent bodies (British Ship
Research Association and Brunel University)
and
on
Peter Ridyard's data. The report
tended to agree that the Derbyshire could
have been lost due to damage in front of the
bridge
in the region of Frame 65. However,
the underwater investigation
in 1997 proved
that the ship had not been
lost in this way.
The Derbyshire families were angered when,
in March 1986, the DOT published the report
in a much modified form, saying that the loss
of the ship could have been due to various
other reasons. The Government said that
the draft report had been changed
in the
light of new evidence but even, when
challenged in the House of Commons, they
would not say what the new evidence was.
Then, on 18th November.1986 the Kowloon
Bridge, one
of the Derbyshire's sister ships,
developed severe deck cracking at Frame 65
while crossing the North Atlantic in severe
weather. In view of the connection with the
Derbyshire, the Department
of Transport's
inspectors boarded the Kowloon Bridge
on
20th November in Bantry Bay, Eire where
she lay at anchor.
But
on 22nd November she broke away from
her anchor and, to be safer, put to sea again.
She then
lost her rudder and on
24th November went aground on Stag Rock
off the south coast of Ireland. On
25th November, after grounding, she broke
her back. The break occurred near Frame
65. It was learnt that cracks in the Frame 65
area
of the Kowloon Bridge had been
repaired
in
April 1982 and that massive
girders had been welded over the deck there
to prevent further cracking.
Following the loss of the Kowloon Bridge,
and the growing suspicion that the
Derbyshire could have been lost because of
a failure at Frame 65, the Government
agreed to hold a formal investigation into the
loss of the Derbyshire. This took place
between October 1987 and March 1988 in

61. Church House, Westminster, under a Wreck
Commissioner, Gerald Darling QC. The
investigation was the longest of its type ever
to have been heard. It took the Wreck
Commissioner 10 months to reach a
conclusion which was
in any case
inconclusive. The
conclusion was
announced
on 18th January 1989
(almost
nine years after the loss of the Derbyshire).
"For the reasons stated in this Report the
Court finds that the Derbyshire was
probably overwhelmed by the forces
of
nature in Typhoon Orchid, possibly after
getting beam on to wind and sea
off
Okinawa in darkness on the night of
9th/10th September 1980, with the loss of
44 lives. The evidence available does not
support any firmer
conclusion."
The Wreck Commissioner gave these
reasons for his conclusions:
1. Even under the weight of severe seas the
ship
would not have fractured amidships.
As the Frame 65 area was stronger than
amidships it is unlikely that failure
occurred there.
2. Fatigue cracking was unlikely to have
caused the total·loss of the ship whether
amidships or af Frame 65.
3. Failure of the hull at Frame 65 due to
brittle fracture was extremely unlikely.
4. Although flooding of the bosun's store
and the chain locker could have caused
loss of freeboard by the bow, followed by
sequential damage and failure to No. 1, 2
and 3 hatch covers, it was thought
unlikely that this caused the loss of the
ship.
The government felt that a search for the
Derbyshire was impossible as her
whereabouts was not known and there was
no
technology to obtain clear photographic
evidence at a probable depth of 4,200
metres.
In June 1990 Tyne Tees Television took up
the fight through the 'Northern Eye' program
Hatch Cover Types
- a
half hour long documentary about the
Derbyshire.
On 29th May 1994 a US organisation,
Oceaneering Technology, commenced a
search for the Derbyshire. This cost
£350,000 and was organised and paid for by
the International Transport Federation (ITF).
An off-shore support vessel called Shin Kai
Maru was used, from which the Ocean
Explorer 6000, a unique dual channel side
scan sonar, was used to search for the
wreck. On board the Shin Kai Maru was a
team from Channel 4 TV who later
broadcast an excellent documentary. During
the days following the loss of the Derbyshire
in September 1980, oil had been seen
bubbling to the surface, by helicopter, and
the positions noted. Based on this it was
estimated that she would lie somewhere
within
an area of
200 square nautical miles.
It was more likely that she lay within an area
of 90 square nautical miles. Against all odds
the wreck was discovered only 23 hours
after the search had commenced.
Deteriorating weather delayed a more
detailed examination and the time that the
ITF had paid for was running out.
Nevertheless, Oceaneering Technology
donated the use of its Magellan 725, a
remotely operated vehicle, to obtain video
evidence to identify the wreck. The bow and
stem were found more or less intact but the
rest
of the wreckage was spread over a large area of about 1500 x 1500 metres
(2.25 sq. km). The cargo holds had imploded
(opposite to exploded) due to the enormous
water pressure that was exerted on the ship
as she sank to the bottom.
Now that the wreck had been found the
Government was forced to take action and
Lord Donaldson was appointed to assess
what further steps were needed to obtain
evidence
on the
loss of the Derbyshire. He
concluded that a second expedition to the
ship was essential, not only to establish why
she sank but also for the benefit
of ship
safety
in
general.
57

62. Hatch Covers -Operation, Testing and Maintenance
Three assessors were appointed to oversee
the expedition and prepare a report. Two
underwater remotely controlled vehicles
would be used, Argo to obtain a broad view
of the wreckage and Jason for a more
detailed inspection. Although the wreckage
was distributed over a wide area the
assessors were surprised that it was as
localised as that, considering the depth of
water. The technical achievements of the
survey were exceptional. 135, 77 4 individual
electronic photographic stills were obtained
of over 98% of the entire wreckage field.
The stills were then joined up to make larger
pictures. Some 2,500 separate items of
wreckage were identified and some 200
hours of video were taken. The Assessors
had a lot of work to do before they could
come to a conclusion and it took them
almost 11 months to publish their report in
March 1998.
The assessors' conclusion was that the lid to
the hatch leading to the bosun's store on the
fore deck had not been secured. Their
evidence for this was that they could see a
mooring rope trailing from it. They also noted
that the wing nuts, which should have
secured the hatch, were not fully tightened.
The open store hatch had allowed water to
fill the void spaces in the fore part of the
ship. The bow
of the ship had then sunk
deeper into the momentous seas, which
soon damaged the hatch
on No 1
hold,
causing it to collapse and the hold to fill with
water. This made the bow go down even
further with the result that the same thing
happened to No 2 hatch and No 2 hold
flooded. And so, one by one, under the
same circumstances the remaining holds
flooded and the vessel sank. The assessors
did not
know how
long this sequence of
events took. It could have been just a few
minutes. The assessors also said that Frame
65 had not caused the loss of the ship.
The conclusion that the bosun's hatch had
not been property secured implied serious
negligence on the part of the crew.
58
On 17th December 1998 the Government
announced that there would be a full
re-opening of the formal investigation in the
High Court. The hearing commenced
on
5th
April 2000 and lasted for 54 days.
Evidence was taken from a number
of
experts. The Court decided that the cover to
the bosun's hatch had not been
left open by
the crew.
The Court concluded that the cover to the
bosun's hatch had probably been destroyed
when one
of the massive
windlasses on the
fore deck was dislodged. Evidence about the
alleged unsecured hatch to the bosun's
store was given
by a previous Chief
Officer
of the Derbyshire. He explained that on
leaving port the forward mooring ropes
would be stowed away in the bosun's locker.
Before lowering them into the locker the end
of each one would be lashe.d to the following
one. Then, to make it easier to get them out
of the locker when they were next needed,
the end
of the
final rope to be stowed would
be lashed to a special bracket on the
underside
of the hatch cover.
It was the end
of this rope which the Assessors saw
protruding from the store hatch that caused
them to draw the wrong conclusions.
This Chief Officer also explained that the
hatch dogs had a nasty habit
of working loose, especially when heavy seas, landing
on top of the lid, compressed its rubber seal.
He knew that the ship's carpenter habitually
secured the lid with a 'cat's cradle' of rope to
prevent the dogs from working loose and it
was most unlikely that the 'cats cradle' was
not
in
place.
The Court learnt from weather hindcasts
(backward looking weather forecasts) about
the sea conditions that the Derbyshire
probably encountered during Typhoon
Orchid.
Before making its decision the court heard
the results of tests on a model of the
Derbyshire that were conducted at the
MARIN Research Institute, Wageningen,
Netherlands. These were designed to

63. measure the forces exerted by heavy seas
on the forward hatches under different
conditions
of trim and wave heights.
It was
established that if the Derbyshire had been
bow
on to the very high waves, and if the
wave
length was similar to the length of the
vessel (about 1,000 metres), then she could
have pitched down into the trough of
successive waves. Before the bow had a
chance to rise back to the horizontal, it
would have been submerged under the next
wave crest.
On the basis of the condition of the
wreckage, the model tests done by MARIN
and the weather hindcasts, the Court
believed that the initiating cause of the loss
was the destruction of the ventilators and air
pipes on the foredeck
by continuous green
water
loading over many hours on 8th and
9th September 1980. The seas then flooded
the bosun's store and the forward ballast
tank causing the ship to trim down by the
bow and eventually sink. This trim was not
perceptible from the bridge because it would
have been obscured by the extremely poor
visibility that was likely at the time due to
driving wind and spray. Also, the bridge was
over 260 metres (8.50 feet) from the how.
The sea started cFashing on to the No 1
hatch cover as the bow dropped lower in the
water: No 1 hatch cover was not designed to
withstand such enormous pressures and
eventually gave way. This caused No 1 hold
to flood and so the bow went down even
more. The same thing then happened to the
other hatches, one after the other, until each
hold filled with water and the ship finally
sank. The Court also concluded that it was
most unlikely that the ship had been lost due
to any other cause, including faults at Frame
65. The Court believed that it was most
unlikely that she went beam on to wind and
sea, as was suggested
in the
Formal
Investigation held in 1987-1988.
The Court made a number
of significant
recommendations to improve ship safety
which are
gradually being implemented by
the International Association of
Hatch Cover Types
Classification Societies (IACS), supported
by IMO.
The new requirements for existing bulk
carriers consist of a set of actions that have
been implemented on almost all bulk
carriers:
1. Earlier implementation of SOLAS
Chapter XII requirements. The objective
is to bring forward the reinforcement of
the corrugated transverse bulkhead
between No 1 and No 2 holds and the
double bottom of No 1 hold. This is now
to be complied with at 10 years for
vessels under 10 years old as of 1st July
2003 and at the due date of the next
Intermediate or Special Survey
(whichever comes first) after 1st July
2003 for vessels of 10-15 years of age as
of 1st July 2003. Previously, these
requirements were applied at 15 years.
The changes are introduced through the
adoption
of a new revision of
IACS UR
S23, which covers the early
implementation of the already existing
IACS UR S19 and UR S22 for existing
single side skin bulk carriers.
This involves reinforcing of the No 1 /2
bulkhead, either by doublers or
cropping/renewing the steel corrugations.
2. Adoption of a new revision of UR Z10.2
(Hull Surveys of Bulk Carriers). This
amended Unified Requirement now
extends ESP requirements for close-up
surveys at Special Survey No 2 and also
requires Intermediate Surveys of bulk
carriers of 10-15 years of age to have
essentially the same scope as Special
Survey No 2.
This means that the more stringent Class
surveys of the third special survey are
brought forward to the second special
survey, ie when the vessel is at or about
nine years old.
3. Extended application of IACS' UR S24,
requiring the installation of water ingress
detection and alarms in all cargo holds of
59

64. Hatch Covers -Operation, Testing and Maintenance
existing bulk carriers, as well as new
buildings.
This involves the fitting of water ingress
monitors
in
all cargo holds with an alarm
panel fitted in the wheelhouse. The
monitoring system can take various
forms, eg, detectors fitted into the hold
after stool to detect at two different levels,
usually 0.5 m and 2 m height.
4. Requirements for the
installation of an
improved bulwark or breakwater on
existing bulk carriers when not fitted with
a forecastle, and a forecastle on new
vessels, to provide more protection for
forward hatches and fore-deck fittings.
5. Requirements to increase the integrity of
fore deck fittings on existing and new
bulk
carriers, to resist green water loading.
Those fittings which are forward of any
breakwater must be protected or
strengthened to prevent failure in green
seas. These can take the form
of a
'U'
shaped steel guard around a ventilator or
the ventilator being strengthened by webs
approximately 200 mm high at 0°, 90°,
180° and 270° around its base.
6. Implementation of hatch cover
requirements within the forward 0.25 L of
existing vessels that are generally
equivalent to UR S21 requirements for
new vessels. UR S21 is currently under
review
for revision
in
light of the findings
of further model tests carried out by the
UK, with input from IACS in conjunction
with the findings
of the
RFI on the loss of
the Derbyshire.
60
Class are currently requiring No 1 and 2
hatch covers to have additional methods
of securing the covers in place. This can
take the form of additional pads welded
around the outside of the covers on the
coaming bar to prevent their transverse
and longitudinal movement. Some early
hatch cover designs have been fitted with
locking pads that locate through a fitting
on the hatch cover down into the coaming
bar (see Figure
5.61 ).
Figure 5.61 -Locating Lug fitted to No.1
Hatch Cover to Conform to
IACS
Requirements
7. Implementation of requirements for the
strength
of side
shell frames of existing
vessels taking into consideration IACS
UR. S 12, which today is applicable only
for side frames of new bulk carriers.
Class may require sideshell frames in
No 1 and 2 holds to be renewed or
strengthened. Strengthening can take the
form
of
doublers or inboard sloped
intercostal webs that provide additional
longitudinal strength to the frames.
8. Fitting of water ingress detection and
alarms for spaces forward of the cargo
area.
The forward deck store is now required to
have a water ingress monitoring system,
often combined with the hold water ingress
monitoring system. The space is also
required to have a remotely operated
de-watering system whereby the space can
be pumped out. This usually involves an
eductor system operating off the fire or
ballast main.
To summarise the above, Class surveys of
bulk carriers have been revised to bring
forward the special 15 year survey to the
second special survey at 9 years. Bulk
carriers are now required to have forecastle
ventilators additionally stiffened, additional
locking devices on No 1 and 2 hatch covers

65. to prevent them from being opened by heavy
seas, together with water ingress monitors
in all holds, water ingress detection and remote
pumping arrangements
in the
forecastle
store, additional stiffening (intercostals) of
No 1 and 2 hold sideshell frames, additional
stiffening of No 1 tanktop and the No 1/2
bulkhead. The design and arrangements for
all of the above must be approved by the
vessel's Classification Society.
When carrying out P&I conditions surveys it
is likely that the Club will require the
surveyor to ensure that the vessel complies
with the above.
5.6 Lift and Roll Covers
(piggy-back)
Generally fitted to combination carriers, bulk
carriers, container ships and multi-purpose
vessels. They are very popular for large
specialised forest product (timber) carriers
and multi-purpose vessels with box holds.
This type is a development of rolling covers.
In theory there is no limit to their size .. There
can
be two
panels for a 26 m x 23 m
hatchway and more for larger hatches.
c:: a 1 r'n ....... + ... •l"'tif"'O"
They are generally constructed with a
double skin type steel pontoon design.
There is a flat steel top fabricated from all
welded steel panels. The sides, ends, and
bottom panels are also of welded steel
panels. The covers are strengthened
internally by thick and deep longitudinals
providing longitudinal strength, with
transverse floors of smaller scantlings to
provide rigidity with the ability to take loads
on top, eg logs.
c:: ~ I') C---1: ... ,... C'.'\/C'.'t" .......
This type of hatch cover may adopt either
the Cat system or double drainage system.
The Cat system tends to be preferred as it
Hatch Cover Types
reduces the amount of clutter on the
coaming
bar.
k. c. '=> cl"\,._, ... : ... ,.. ,..ii"\,"""'"'
Hatch covers are held in position by large
quick acting cleats or set bolt cleats around
the sides and ends. Set bolt cleats may be
spaced out across the
top
of each cross
joint.
Set bolt cleats may also be fitted at the
cross joint sides which, may be vertical or
horizontal across the joint (see below).
C:: C. A I'") .... ,.,..-.. '-1,.. ......
In the two panel configuration at Figure 5.63,
one
of the
panels has a minimum of two
wheels to each side. This panel is not lifted.
The panel immediately adjacent to the first
panel does not have rollers but has side
protruding lugs that align with long vertical
hydraulic jacks fixed in the hatch coaming
(see Figure 5.64). The hydraulic jacks are
used to lift the panel clear of the coaming,
high enough for the rolling panel to roll
underneath. When the rolling panel is in
position the jacked panel can be lowered on
top
of the
rolling panel. The two panels can
then
be moved forward and aft to make
hold
space available for cargo operations. The
panels are moved either by windlass
operated chains or internal electric motors
driving the wheels via a gearbox (see Figure
5.65).
With a four panel configuration, the other set
are
of the same configuration, one with wheels and one with jacking legs. This
means that either 25% or 50% of the hatch
area can be made available for cargo
operations.
61

66. Hatch Covers -Operation, Testing and Maintenance
Figure 5.62 -Piggy Back (Rolling) Hatch Covers (Note Also the Use of Sealing Tape)
62
Fig 5.64 -Hydraulic Jacks Used to Lift
Piggy-Back Hatch Cover
(Courtesy of MacGregor Group)
Fig 5.65 -Piggy Back Hatch Cover Electric
Wheel Drive Motor
(Courtesy of MacGregor Group)

67. Hatch Cover Types
r~~i-tt fl ?@ (j-ii D~
II
II
___ _Jj /'
____ IP!'/
Fig 5.63 -Diagram Showing (Chain Driven) Lifting Arrangement for Piggy-Back Hatch Covers
(Courtesy of MacGregor Group)
63

68. Hatch Covers -Operation, Testing and Maintenance
,,...,
Panels are not removed from the coaming
but slide to either end of the coaming to
allow access to hold areas. While the side
chains will prevent covers from moving,
locking pins are also fitted to prevent
movement.
As ships using this type
of hatch cover
become
larger and hatches become wider,
the panels become heavier, needing
significant rollers and hydraulic jacks. The
advantages of these covers
is that they do
not
vertically stow or need to be landed
ashore for storage during cargo operations.
While operating the covers can be achieved
relatively quickly, their one disadvantage is
that the whole hatch area is not made
available for cargo operations. A maximum
of one half of the hatch area only is made
available at any one time, so cover panels
must be rolled backwards and forwards to
give access to other areas. The design
incorporates large, long hydraulic jacks that
need regular maintenance and adequate
protection from the elements.
When inspecting this type of hatch cover the
following should be reported on:
64
Seals -report if heavily grooved,
hardened, damaged or missing
watertightness test results
hatch wheels greased and free
condition of hydraulic jacks and pipes -
report if leaking or wasted
condition of drains and non return
assemblies
the tightness and condition of side cleats
the condition of the coaming and
coaming bar
the condition
of the
panels, hinges, etc.
5. 7 Sliding Tweendeck
Covers
Tweendeck hatch covers are made up of a
number
of two section
plates that slide
under each other to expose the hatchway.
When closed they are flush with the
surrounding deck, facilitating the use of fork­
lift trucks. They can support normal loads
and the weight of fork-lift trucks carrying
cargo. These covers are not generally
required to be watertight. Additional sealing
will be used if tweendecks are to be used for
bulk cargoes, with other cargoes being
stowed
in
lower hold spaces.
Tweendeck covers have a flat steel top
fabricated
of
all welded steel panels, with
the leading edge face plate also made of
welded steel.
Some older covers were wire operated with
later versions operated by means of
hydraulic or electric motors operating pinions
on the sides
of the
leading cover panel,
which engage in a rack along each side of
the opening. When closing, the leading
panel pulls the other panels. When opening,
the other panels slide over each other until
the leading panel is in the open position.
Figure 5.66 -Sliding Tweendeck Hatch
Covers
;:

69. ""7 ') fl"\· .. £
As may be seen from Figure 5.66, the
panels slide under each other to one or both
ends of the tweendeck space with a
walkway left around the sides and ends of
the space.
"*7 A c""• ..... : ..... ,.... """""''•'""'
Cleats may be used to lock panels in the
closed position. These will be
accommodated in slots to ensure that the
tweendeck surface
is not obstructed.
r::7c:;. r f,..
This is a relatively simple design. However;
like other hatch covers, they require regular
maintenance. Cover links, racks and pinions
need regular greasing
When inspecting this type
of hatch cover the
following should be reported on:
Hatch wheels greased and free
condition
of
hydraulic pipes -report if
leaking or wasted
Cover spreader
lifting lugs~
,~,t,,
,...,~
Device for container
lashing
~·
,.
,.-
.. -
,
Hatch Cover Types
condition of tracks
the condition
of the
panels, hinges, etc.
5.8 Pontoon Covers
Sometimes known as Lift-Away hatch
covers. Generally fitted to roro, lolo,
container and heavy lift vessels. Container
vessels can range from 200 to 12,000 teu
capacity. The small vessels may have only
one hatch cover fitting across the hatch
while the larger vessels may have twin,
triple, or four panels across the width of the
hatch
opening. The
panels will be slightly
longer than 40 feet so that when removed
they allow access to a set of 40' cell guides.
,.. '"' .... r,.... ......... f.,., ..... f;,... .....
Smaller vessels may have single skin
covers. The flat steel top is fabricated from
all welded steel panels. Sides, ends and, in
the case of box type, bottom panels, are
also made of welded steel panels. They are
strengthened
by thick and deep
longitudinals
Stacked pontoon
•
,.
..-...
-t ...
..
,-
-"Ill& • Securing device
Figure 5.67 -Container Vessel Hatch Pontoon Configuration
65

70. Hatch Covers -Operation, Testing and Maintenance
Figure 5.68 -Feeder Container Vessel Hatch Covers
providing longitudinal strength, with
transverse floors of smaller scantlings to
provide rigidity with the ability to take
significant loads on top. As ships using this
type of hatch cover become larger and
hatches wider, the panels become heavier.
To keep weight to manageable levels, more
panels are used so that larger vessels may
have twin, triple, or quadruple panels across
the width
of the hatch opening.
As covers are independent and not
linked to
each other or to any opening/closing
system, they are fitted with locating devices
that allow them to locate quickly and
properly when lowered into place. The top
face
of the covers are fitted with various
types
of equipment to accommodate
containers, eg, container cone sockets,
lifting sockets, 'D' rings or lashing plates,
etc.
The cover panels are often fitted with heavy
duty lugs on the upper face to allow other
pontoons to be stowed on top.
66
Figure 5.69 -Container Hatch Cover Showing Locating Lug and Cleat
Figure 5.70 -Hold-Down Cleat
(Courtesy of MacGregor Group)

71. 0 I') C' "'"'' ... ·
"' ''"'",.....
Quick acting cleats of sizes appropriate to
the hatch cover size are adopted around the
cover perimeter, particularly on feeder
vessels that have fast turnarounds. Vessels
on longer liner trades may have set screw
type cleats. Covers may also be held in
position by hold-down cleats (See
Figure 5.70).
As may be seen, while there is no
adjustment with the hold-down cleat, it is
quick and easy to operate.
,.. n ~ f"\nenjng/~10 ..... ;...,.,....
Before removing covers, cleats must be
removed. Sockets are welded on the panel's
top face to allow panels to be lifted off by a
container spreader, either
by the ship's
cranes or
by shoreside container cranes
(see Figure 5.71).
r=
Figure 5.71 -Container Spreader About to
Lift Hatch Cover
A
c+,... ... ,,.,.l"tO nf r ......
Panels can be stowed on top. of each other
to provide access to the relevant container
bays, although at larger container terminals
they are lifted off the ship altogether and
Hatch Cover Types
stowed on the quay on the other (inboard)
side
of the container crane, with container
trucks passing under the crane.
5
0 c::. c .......... prq l"'\ll"' ... .-
Both the double drainage and Cat system
are used
by container
vessels, irrespective
of size and trade. Variations on the Cat
system are also used, with seals of various
profiles acting on the flat coaming bar.
There are many designs of cross joint
sealing. In some vessels with three panels
athwartships, there is no cross joint seal at
all between the centre and outboard panels,
there being a 75 mm high wash plate or weir
fitted on the cover panels, each side of the
cross joint gap. Other designs are shown in
Figure 5. 72.
-r!)
.K"'
J
1'-, J
Sequentiajoint Sliding joint
1r1
,...........__, ,q""'
I ]
Double rubber lip seal Open joint with drainage
.I<=>
.............
Omega joint Opm joint. no drainage
Figure 5.72 -Container Hatch Cover Cross
Joint Designs
(Courtesy of MacGregor Group)
67

72. Hatch Covers -Operation, Testing and Maintenance
Some ship operators have a misconception
that container ship hatch covers do not need
to be weathertight, the cargo being
protected
in
steel containers. However, P&I
Clubs and cargo underwriters do not agree
with this belief. There is always the
possibility
of
hold bilge wells being blocked,
preventing discharge of hold water, creating
a stability problem and damage to the
contents
of
lower containers.
On larger vessels each container hatch
cover can weigh up to 40 tonnes, which is
taken by the four lifting sockets when being
lifted and lowered. There have been some
serious accidents with containers falling
from significant heights so you are well
advised to keep clear of container lifting and
lowering operations.
While container cranes are generally stable,
the spreader tends to swing at the bottom of
its travel. With the ship also tending to move
at its moorings, it makes it difficult to locate
the spreader in the sockets, the spreader
often contacting and damaging other fittings.
When being lifted, the pontoons can also
swing and cause damage to locators,
ventilators, etc.
When inspecting this type
of hatch cover the
following should be reported on:
• Seals -report if heavily grooved,
hardened, damaged or missing
watertightness test results
hatch wheels greased free
condition of drains and non return
assemblies
the tightness and condition
of side
cleats
• the condition of the coaming and
coaming bar
68
the condition of the
panels
condition of locating lugs.
5.9 Reefer Vessels
Hatches and hatch covers are usually small
to prevent thawing of the cargo during cargo
operations. The frozen cargo
is
usually
landed through the hatch and stowed using
fork-lift trucks. There may be several
tweendecks, which may be common, ie all at
the same temperature, or they may be
sealed from each other to allow stowage of
cargoes at different temperatures.
Tweendecks are usually of the hydraulic
folding type. The sealing system used for
reefer vessels is similar to the double
drainage system, but with additional
insulation rubber packing installed to seal
the space (see Figure 5.73). If leaks were
allowed to pass the seal there is a danger of
covers becoming frozen in place. Hatch
cover panels are of the hydraulic ram
operated folding type, generally small, and
with only two panels and of box
con~truction. ·
When inspecting this type of hatch cover the
following should be reported on:
Seals -report if heavily grooved,
hardened, damaged or missing
watertightness test results
condition of hydraulic pipes -report if
leaking or wasted
condition
of drains and non return
assemblies
the tightness and condition of side cleats
the condition of the coaming and
coaming bar
the condition of the panels, hinges, etc
condition of insulation.

73. Hatch Cover Types
'Z4',-7.J.:.Z
;
Hillth cover
/f
Insulation
~
Insulation rubber r
.-,
Insulation rubber
Hatch side and ends Cross joint
Figure 5.73 -Reefer Vessel Sealing System
Figure 5.74-EVA Sealing System
5.10 Other Sealing
Systems
While I have tried to cover the most popular
hatch cover sealing systems, there are other
less used systems in use around the world.
5.10.1 The EVA sealing
-.. ,.,.... ..
The seal is formed by a double rubber seal
acting into a groove or channel, the theory
being that two seals are better than one.
-t f ') Ti,..-r'\_.,.,.,. __ -· ·-f.,.,....,..
This system is similar to the CAT system in
that the seal is a tubular section with a
leading edge pressing against a flat surface.
c:: -1 f ") nn+,.,.f.:"",.. 4=,...,... ,...
Not seen for some time although some
vessels may have the system fitted. The two
hatch covers are landed in position. On the
face
of one cover is a rotating compression
bar
while there is a rubber seal on the other
that can be rotated into position. The crew
turn handles at the hatch cover side, which
rotate the seal or compression bar from a
housed position to make contact with each
other. The system was not popular due to
the maintenance required and the tendency
for one or other to seize when
in
place.
69

74. Hatch Covers -Operation, Testing and Maintenance
5.11 Other Hatch Cover
Designs
I have attempted to cover most hatch cover
types and there will always be variations on
a theme. Generally, hydraulically operated
hatch covers are fore and aft folding or side
sliding. However, from time to time the
reader may see some variations on these.
One such variation was recently seen in a
Chinese shipyard. These were side folding
hatch covers as shown in Figures 5. 75 and
5.76.
70
Figure 5.75 -Side Folding Hatch Covers in
Closed Position
Figure 5.76 -Side Folding Hatch Covers in
Open Position
5.12 Other Cleating
Methods
While there are a number of standard
cleating designs in use to secure hatch
covers the reader may find other less
popular designs in use. One such design is
the claw type cleat. Claw type cleats are
spaced around the edge
of the hatch cover
which, when the hatch cover
is
closed and
lowered, protrudes down through a gap in
the coaming bar. A hydraulically operated
sliding bar slides into the claw to hold the
hatch cover
in position.
Figure 5. 77 -
Claw Type Cleat Fitted to Side
Sliding Hatch Cover
Figure
5. 78 -
Hydraulically Operated Sliding
Bar in Open/Unlocked Position

75. igure 5.79 -Hydraulically Operated Sliding
Bar in Closed/Locked Position
As it is difficult to see if this type of cleat is
locked or unlocked, some form of indicator
is fitted as shown in Figure 5.81.
Hatch Cover Types
Figure 5.80 -Claw Type Cleat in Locked
Position
Figure
5.81 -
Claw Type Cleat Hydraulic Connections and Locked/Unlocked Indicator
71

77. The Difference Between Watertightness and Weathertightness
6 The Difference
Between
Watertightness and
Weathertightness
There is a
particular requirement in respect
of both 'weathertightness' and
'watertightness' for ship's hatch covers.
Weathertightness must ensure that the
tightness of hatch covers can
be maintained
in any sea condition.
Watertightness
is the prevention of the
passage of water through the structure,
in
any direction.
The
International Maritime Organization
(IMO) defines watertightness as being
Figure 6.1 -Ram-Nek Tape in Use on Side Sliding Hatch Cover Cross Joints
75

78. Hatch Covers -Operation, Testing and Maintenance
capable of preventing the passage of water
through the structure
in either direction, with
a proper margin of resistance, under the
pressure
of the maximum head of water that
it might have to sustain.
Weathertightness is defined as the non­
penetration
of water into the
vessel in any
sea condition.
Some P&I Clubs differentiate between the
two definitions
by stating that an
ultrasound
reading of zero will be interpreted as the
hatch cover being watertight, while any
reading up to 10% will be accepted as
weathertight. Any reading above this will be
defined as non-watertight.
6.1
· Ram-nek Tape and
Foam
The surveyor may find evidence that hatch
sealing tape or high expansion foam has
been used
in an effort to make hatch covers
watertight, often required
by Charterers.
P&I
Clubs frown on the use of either, stating that
all hatch covers should be maintained in a
weathertight condition.
Sealing tape can accelerate corrosion and
give a false sense of security, as it may be
washed away
by heavy seas.
It can also
prevent water draining from cross joints and
promote deterioration
of the
panel edges.
High expansion foam may also be found
around the edges
of the covers. There is usually very little adhesion to the coaming
bar so that it can be washed
away, again
giving a
false sense of security. There is also
the risk that it could damage the hatch cover
seals.
Blocked drain valves may also contribute to
water ingress to the holds. Cement or light
ores can cause blockage of the drain valves.
In this event it is often the practice to remove
the non-return drain v~lves and replace
them with a length of fire hose, which should
be long enough to freely bend back on itself,
usually around 3 ft or 900 mm. This can
prevent water ingress and
is considered by P&I Clubs to be a temporary solution for
damaged non-return valves.
Figure 6.2 -High Expansion Foam in use on Side Sliding Hatch Cover Coaming Bar
76

80. 7 Care and
Maintenance of
Hatch Covers
Shipowners, shipmanagers and those
involved in the operation of hatch covers
should be aware of the need for regular and
appropriate care and maintenance
of these essential structures. A visual examination by
an experienced inspector can reveal many
defects.
Regular maintenance is essential. A small
amount of regular maintenance can prevent
the need for significant repair work later.
Maintenance generally involves:
Keeping component parts clear of rust
and debris
repairing and replacing parts where
necessary
painting and greasing
of various
relevant
parts.
Figure 7.1 -Internal Hatch Coaming
Showing Indications of Leakage from
the Inner Drain Channel
Care and Maintenance of Hatch Covers
Figure 7.2 -
A Poor Attempt to Hide
Corrosion
of
Inner Hatch Coaming
Inspections should be carried out by ship's
personnel as often as possible, there being
much at risk if thorough inspections are not
carried out. It is also advisable to keep
records
of inspections and maintenance as
such records may be requested during
insurance
claims and can show that
owners/operators have acted
in a prudent
and
diligent manner.
Inspect rubber packing for wear, damage
and over-compression. Seals should not be
painted. If over-compression is found, check
the condition
of the bearing pads or hatch
cover edges, depending on which type
of
bearing system is used.
If the imprint/groove
in the rubber seals is off centre, check to
see if the cover panels are misaligned. This
may be caused by worn hinges and/or
corroded steel-to-steel locating lugs.
A thin film of manufacturer approved grease
may be applied to the rubber seal to prevent
excessive friction. Always replace damaged
79

81. Hatch Covers -Operation, Testing and Maintenance
Figure 7.3 -Some Typical Hatch Cover Defects
and heavily worn seals with manufacturer
recommended materials. Thoroughly clean
the seal channel before applying the glue
and fitting the seal. Ideally, seals should be
renewed every five years as they tend to
become hardened over time due to a
combination
of a number of factors,
including ultraviolet light.
Compression bars should be checked for
corrosion wastage and damage. Whether
manufactured
of
mild or stainless steel, the
height
of the compression bar
should be
measured to ensure that it meets design
standards. Mild steel compression bars
should be painted, straight and level. While
the outer sides and ends of the hatch cover
panels form the first barrier to water ingress
and the rubber seal the second barrier, the
inner drain channel forms the third barrier.
The inner drain channel should therefore be
maintained
in a
clean and dry condition so
that, when opened, leaks may be detected.
80
Figure 7.4 -Misaligned Port Side Sliding
Hatch Cover Outboard Seal

82. Care and Maintenance of Hatch Covers
Figure 7.5 -Severely Wasted Locating Lugs Causing Misalignment
of
Cover Panels
The inner drain ch~hnel should also be kept
free
of any obstructions that
will allow any
water ingress to drain down to the non­
return drain traps at the port and starboard
after corners. These drain valves should be
checked regularly to ensure that they are in
place, fitted, clear of any obstructions and
working correctly.
Trackways permit the smooth opening and
closing of the covers and should be checked
for distortion, cracks and unevenness. They
should be maintained in a clean, rust-free
condition.
All moving parts should be checked for
correct operation. If covers are operated by
chains, they should be checked for equal
length each side and excessive stretching. If
a chain windlass is incorporated the drive
sprocket wheels should be checked for
excessive wear and replaced if necessary.
Cleats should also be checked for correct
adjustment and operation.
Figure 7.5a -Poorly Adjusted Coaming
Track
81

83. Hatch Covers -Operation, Testing and Maintenance
Figure 7.6 -Heavily Corroded and Wasted
External Bearing Pad With No Contact
Figure 7.7 -Heavily Corroded and Wasted
Internal Bearing Pad
Hydraulic systems should be inspected,
particularly pipework, for corrosion and
leakage. These are generally wrapped in
grease impregnated cloth bandages to
prevent corrosion. Check that flexible pipes
are not painted or cracked and that
connections are not leaking. Check hydraulic
oil levels in the pump header tank and top
up to the required level when necessary. Do
82
not overfill as the oil expands with higher
temperature and may overflow. The pressure
differential across filters should also be
checked. If this is too great, the filters
should be cleaned or changed (disposable
type). Hydraulic oil samples should be taken
and landed with the Chief Engineer's oil
samples for analysis.
Bearing pads should be checked for wear,
corrosion and correct height. Bearing pads
can be fitted externally. Exposure to the
elements and the abrasive movement
between the cover and coaming can cause
accelerated corrosion and wear (see
Figure 7.8). This can also apply to internally
fitted bearing pads, as shown in Figure 7.7.
Consequently, it is advisable to lightly grease
the surfaces
of
steel to steel contact areas.
In the case of hatch cover-s that rest on the
coaming
bar, the coaming bar and cover panel edges should be checked for
corrosion and wastage as this will also
cause the panels to drop, with resultant
heavy grooving of seals.
Figure 7.8 -Severely Corroded and
Wasted Coaming Bar Where Hatch Cover
Panel Edge Locates

84. Sufficient spare parts, particularly spare
seals and hydraulic pipes, should be carried
onboard so that voyage repairs can be
carried out when and where necessary.
Bearing pads are one
of the most
critical
parts of the hatch cover system and are
frequently neglected. If not greased before
each voyage they will corrode and waste,
causing the hatch covers to drop and seals
to become heavily grooved. As the seals
become more heavily grooved the seal
rubber material passes through the elastic
phase and into the plastic phase and
hardens. With no elastic compression, the
seals will leak. Repairs will involve replacing
or shimming up the bearing pads and
renewing all seals. A little care can save a lot
of time and expense.
When operating the hatch covers, observe
every precaution. Death or serious injury
can result where appropriate procedures are
not followed.
As with all other shipboard equipment, the
ship's crew should operate the hatch covers.
Others could be held liable for damage to
any equipment they have operated. ·
Always stand back and give those who know
best how to operate the equipment the
opportunity to do
so. When inspecting the
covers it
is
also advisable to be in a position
where you can instruct the operator when to
stop or start the opening or closing process.
Never stand
on top of moving hatch covers.
Where
possible, hatch covers should be
operated
in
daylight. If this is not possible,
ample lighting should be in place so that all
areas can be clearly seen. At least two crew
members should be involved, one to operate
the controls and the other to ensure the safe
operation
of the hatch covers. This man should also be in charge of ensuring that all
personnel are clear of the covers when they
are operated. As operation
of the covers is
often noisy, it is
advisable for walkie-talkie
radios to be used to ensure clear and
audible instructions. Alternatively, a common
Care and Maintenance of Hatch Covers
and practiced hand signal system should be
used. All securing devices should be
released. After releasing it is good practice
to walk around the covers twice to check.
Safety devices such as retaining pins,
arrestor chains and other safety catches
should be readily available for use.
When ready to open, the unit supplying
power, ie deck crane/wire, hydraulic pumps,
etc, may be started. When opening, hatch
cover or coaming track lifting devices should
then be raised and the covers raised. As the
covers open, check for uneven or jerky
movement and any vibration. Stop opening if
anything untoward
is found and check for faults. When opened, ensure that the
primary and back-up locking devices are in
place. Switch off the power to motors,
cranes or windlasses.
When closing, ensure that the coaming bar
and drain channels are clear of debris,
cargo remnants and dirt. As for opening, at
least two crew members should be involved,
one to operate the controls and the other to
ensure the safe operation of the hatch
covers. Switch on the power to operating
units, eg deck crane/wire, hydraulic pumps,
etc, and take the load, opening slightly so
that locking mechanisms can be released.
As the covers close, check for uneven or
jerky movement and any vibration. Stop
closing if anything untoward is found and
check for faults. When closed, release the
raising devices, eg wheels or track, to lower
the hatch covers on to the coaming bar.
Apply securing devices and switch off power
to the operating devices.
In colder weather hydraulic oil becomes
more viscous,
ie it thickens, reducing the
efficiency
of the system.
It is often good
practice to start the hydraulic pumps well
before operating the hatch covers to allow
the oil to warm up. (This is generally good
practice as it gives time to find any defects
in
the
hydraulic system.) In temperatures of
less than 5°C heaters should be employed.
Special grease is also available for vessels
regularly operating in colder temperatures.
83

85. Hatch Covers -Operation, Testing and Maintenance
All snow and ice should be removed from
panels before opening due to the additional
weight and stresses on the hatch cover
operating system.
In hot weather, the converse applies, as
there are coolers fitted to hydraulic oil
systems that should be operated before and
during operation
of the hatch covers. Special high temperature grease is also
available. Normal grease tends to melt in
higher temperatures and could cause a
pollution hazard and danger to crew.
Opening hatch covers after rain should not
be a problem for most vessels. Chevron type
steel weirs, approximately 50 mm (2 inches)
high, are fitted to the upper surface of
panels near their lowest edge when opened.
If the covers are opened so that they are
only slightly inclined, any rain water will run
down to the chevron and then off the sides
of the covers to the coaming bars and drain channels.
84

87. Reasons for Hatch Cover Testing by Various Organisations and the Role of the Marine Surveyor in these Tests
8 Reasons for Hatch
Cover Testing by
Various
Organisations and
the Role of the
Marine Surveyor
in
these Tests
There are various organisations
involved in
the survey of ships, some of which are listed
below. Some types of surveys may have
been omitted as only those relating to hatch
cover inspections and testing are included.
8.1 National Based
Survey Organisations
These are generally the Marine
Departments or Ministries
of Transport of national governments, eg, the United
Kingdom Maritime and Coastguard Agency
(MCA) or the Hong Kong Marine
Department, whos~ role is to ensure that
vessels flying their national flag meet
statutory requirements established by the
department and usually in line with
international conventions established by
IMO. The organisation will have surveyors,
who are Government employees, present
during a vessel's construction and for
occasional surveys. Government surveyors
may also be involved in accident
investigations where their flag vessels have
been involved.
These departments are usually also
responsible for supplying Port State Control
Inspectors who visit vessels entering their
ports to ensure that they meet the
requirements
of
international conventions.
The scope of such surveys is usually very
broad and not necessarily technically very
deep, except
in the case of accident
investigations. The Government surveyor
will
normally accept the Loadline Certificate
issued
by the
vessel's Classification Society.
There is therefore not usually a requirement
to carry out hatch cover testing. However, if
the surveyor has doubts about the hatch
covers he may subcontract
an independent
surveyor to carry out
ultrasound testing.
8.2 Classification
'.
Societies
Classification Societies, or Class as they are
commonly known, are commercial
organisations who are in competition with
each other. They were originally established
on behalf of hull and machinery insurers to
ensure that ships met certain standards
of
construction.
Over the years, Class have
developed the standards to which vessels
and their equipment are designed,
constructed and maintained. It should be
borne
in mind that
Class's client is the
vessel's owner and not the insurer.
Class surveyors are required to carry out
periodic statutory surveys, which include the
Loadline Convention. As part of the Loadline
surveys the surveyor is required to prove
that the hatch covers are weathertight. At
the request
of owners,
Class generally use
hose testing only.
Owners regularly complain about the
number and duplication of surveys of their
vessels. By combining the Loadline and P&I
Club hatch cover testing, such duplication is
reduced. As Class do not carry any
ultrasound equipment, they are generally
content to witness a P&I Club surveyor's
ultrasound testing and, if any defects are
found, to carry out hose tests
in the defect locations only. If Owners request ultrasound
hatch cover testing only Class will often
appoint a subcontractor
such as MacGregor.
87

88. Hatch Covers -Operation, Testing and Maintenance
8.3 Independent
Surveyors
Independent surveyors may be requested to
carry out different types
of survey on
behalf
of different types of clients. Some of these
are listed below:
8.4 Insurance Surveys
There are two forms of marine insurance,
hull and machinery (H&M) and P&I
insurance (P&I). H&M surveys are usually
carried out by Class on behalf of the owner.
P&I insurance is a little more complex. P&I
clubs were formed by several owners
coming together to mutually insure each
other's vessels for those risks not covered by
H&M insurance, eg, cargo damage, crew
injury and pollution. Each owner annually
contributes a monetary amount relating to
the gross tonnage he owns, known as the
'call'. The fund is supervised by a
management company,
eg Thomas
Miller
are the managers for the UK P&I Club,
Charles Taylor for the Standard P&I Club
and Skuld. Some P&I Clubs also offer H&M
insurance to their members,
eg The Swedish Club.
While some Clubs use their own inspectors
to carry out visits to the Club's vessels,
independent surveyors are usually
appointed to carry out full entry, periodic
follow-up and damage surveys on their
behalf to identify the Club's risk exposure.
This puts the surveyor
in a
difficult position
as he is appointed
by the managers to carry
out a survey on a member's
vessel, ie he is
'piggy in the middle' and as such should
have a good 'bedside manner'.
Such condition surveys are wide ranging
and comprehensive
in nature, covering the vessel's structure and operational aspects.
As P&I cover includes cargo damage, the
surveyor will be asked to carry out hatch
cover testing. In the event that the hatch
covers are found to be defective, the P&I
Club may impose a warranty on them, ie the
88
Club will not pay for any claims resulting
from hatch cover leakage until such time as
the warranty has been lifted. The Club will
require a follow-up condition survey to be
carried out to ensure that any defects have
been rectified.
The hatch cover survey should not be limited
only to testing for weathertightness. It should
also include the crew skills in operating the
hatch covers, so the surveyor should witness
both opening and closing.
Often, where there have been cargo claims
against a vessel as a consequence of
wetting, the surveyor may be requested to
carry out a specific weathertightness survey
of hatch covers, which may
include a survey
of hold ventilators, bilge wells, coamings and
access hatches.
8.5 Cargo
Surveys
These may be carried out on behalf of
cargo underwriters and insurers, cargo
shippers, cargo consignees and charterers.
The type
of surveys
include pre-loading,
loading/stowage, outturn and damage
surveys. As damage to cargo can result from
leaking hatch covers, the damage surveyor
may also be requested to carry out
watertightness tests. However, the latter will
need to be agreed between the owner and
party requesting the hatch cover tests.
8.6 On/Off Hire
Surveys
Both the vessel's owners and charterers (the
entity hiring the ship) may request
an on hire
or off hire survey before and after a charter
to ascertain the
vessel's condition. Generally
it will be the owner who appoints a surveyor
to carry out the on hire survey, while the
charterer will appoint a surveyor to carry out
the off hire survey. The surveyor should be
aware that the
on hire survey report
will be
used later, during the off hire survey, to
identify damage sustained during the
charter. When high value cargoes are to be

89. Reasons for Hatch Cover Testing by Various Organisations and the Role of the Marine Surveyor in these Tests
carried, the more prudent charterers may
request the surveyor to carry out hatch
cover testing. Again, this will need to be
agreed between the owner and charterers
beforehand. Generally, clients also need the
hatch dimensions.
8. 7 Pre-purchase
Condition Surveys
This type of survey is
usually carried out on
behalf of prospective buyers of the vessel.
Prior to the survey, the owriers and
prospective buyers agree the scope and
extent of the survey, which is usually only
visual in nature. Generally, no written
information or technical testing will be
allowed, which includes hatch cover testing.
Any attempt to exceed the range
of the
inspection
could result in the surveyor being
asked to leave the vessel. However, an
experienced surveyor should be able to
carry out a thorough inspection
of the hatch
covers and report accordingly.
Clients will
also need hatch dimensions.
Figure 8.1 - Indications of Hatch Cover
Leakage
As seen from Figure 8.1, the surveyor's visual inspection should indicate where
hatch cover leaks have occurred. The
surveyor can then expand his investigation
to discover the reasons for the leakage. He
should be particularly suspicious if the
coamings are freshly painted directly over
corrosion.
Whoever the client, the surveyor will be well
advised to follow the requirements of
Section 3.4 of Resolution MSC.169(79)
'Standards for Owners' inspection and
maintenance
of
bulk carrier hatch covers', a
copy
of which is attached at Appendix 1.
This provides
an
excellent visual check-list.
As experienced as a surveyor may be, there
is always the possibility of missing an item
or area when carrying out inspections. There
is no shame in carrying a
clipboard with a
check-list as an 'aide memoir'. A suggested
check-list, which should suffice for most
surveys (which does not include
weathertightness testing), is provided as
Table 8.1 overleaf.
.....
....
'·
I It
Figure 8.2 -Indications of Hatch Cover
Cross Joint Seal Leakage on a Coal Cargo
89

90. Hatch Covers -Operation, Testing and Maintenance
Hatch Cover Inspection Check-List
Ship: Port: Date:
Hatch No:
Item Condition Action
1 Hatch cover panels:
Side plates
Top plates
Stiffeners
Alignment
2 Coaming structure:
Side and end plates
Stays
Coaming bar and drain channels
Wheel trackways
Bearing pads
3
Sealing arrangements:
Seals
Channels
Cross joints
Compression bars
Non return valves
Cleats
4 Opening/Closing mechanism:
Hydraulic jacks
Hydraulic pipes
Hydraulic rams
Hydraulic windlass
Chains
Rollers
Guide rails
Track wheels
Stoppers
Wires
Tensioners
Gypsies
Safety devices and interlocks
Hinges, pins, stools
5 Additional Remarks: (eg, condition of hold, evidence of leakage, etc)
Signed Signed Signed
Master Superintendent Surveyor
Table 8.1 -Suggested Hatch Cover Inspection Check-List
90

92. 9 Various Hatch
Cover Testing
Methods
Hatch covers are
generally required to be
weathertight and not necessarily watertight.
The statutory requirement contained
in Regulation 3(12) of the International
Convention on Load Lines, 1966, states that:
'Weathertight'
in relation to any part of a
ship other than a door in a bulkhead
means that the
part is such that water
will
not penetrate it and so enter the hull of
the ship in the worst sea and weather
conditions likely to be encountered
by the
ship in service.'
It should be pointed out that neither hose
nor ultrasound tests can duplicate the
conditions experienced when a ship is
in
high seas with green seas washing over the vessel's decks and hatch covers. This is why
hatch cover testing
is
only a part of the loss
prevention process. Well maintained seals,
cleats, drains and other components will
assist in maintaining weathertightness.
For many years, the only way to
meaningfully test hatch covers for
weathertightness was with a hose test or
in
the
real thing, a Force 10 storm. The only
other way was to carry out a thorough
inspection
of the covers and coamings to
check for indications
of
leaks and this is still
good practice. In the early 1990s the
principal of ultrasound was first embraced in
the testing of hatch covers by SOT of
Belgium, followed closely by Wylam Hill of
the United Kingdom.
Prior to the availability of ultrasound testing
equipment the traditional methods
of testing
hatch covers for watertightness were:
1.
Chalk test.
2. Light test.
3. Hose test.
4. Air test.
Various Hatch Cover Testing Methods
5. Putty or
moulding clay test.
9.1 Chalk Test
This test requires only one surveyor. The
hatch covers are opened and white or yellow
chalk is rubbed on to the compression bar
top edge. The hatch covers are then closed
and cleated to ensure full compression of
the sealing rubbers.
The hatch covers are then opened partially
to enable examination of the sealing
rubbers. A continuous chalk line on the
rubber seals means that the hatch cover is
weathertight. The thicker the chalk line on
the sealing rubber, the greater the pressure
and more watertight the hatch cover. A thin
line indicates a lack of full pressure with
what is termed 'weathertightness'. Any gaps
in the
chalk line indicate lack of pressure
between the compression bar and the
rubber seals indicating a lack of
watertightness. The longer the gap, the
greater the leak.
Limitations:
Must be carried out
in dry conditions
disrupts cargo operations ~ is not effective in assessing weathertight
integrity.
9.2 Light Test
This test requires
only one surveyor. The
hatch covers are closed and cleated. The
surveyor enters the hold and stands in the
centre
of the tanktop or tweendeck. Any holes in the hatch covers, decks and
coamings, or leaks in the rubber seals may
be seen as light shining through the gap.
The brighter the light the larger the hole.
Limitations:
Must be carried out in daylight and with
an empty
hold or empty tweendeck
disrupts cargo operations.
93

93. Hatch Covers -Operation, Testing and Maintenance
9.3 Hose Test
This test is based on the principle that where
there
is contact between the
seal and
compression bar water will not enter the
hold.
The hatch covers are closed and cleated. A
fire hose
is rigged with a jet type
nozzle
fitted. Water pressure of 2 to 3 bar (30 to
45 psi)
is
supplied to the fire hose, which is
then played at the hatch cover sides and
cross joints
in way of the
seals,
approximately 1-1.5 metres (3 to 5 feet)
away from the area to be tested while
moving at a slow walking speed. Where
cross joints cannot
be accessed it is
usual
for the cross joint ends to be dammed or
blocked and the cross joint space filled with
water to provide a hydrostatic pressure on
the seals.
If there are leaks the water will generally
enter the inner drain channel before
overflowing into the hold. It is therefore good
practice to monitor the non-return drain
valves during the test. If there is a shortage
of manpower, a plastic bag fitted to the drain
valve outlet may be recovered and checked
later. If there is water in the bag it means
that the drain valve is working, the drain
channels are clear but that the hatch cover
seal is leaking. If the bag is empty but water
enters the hold, either the drain channels
are blocked or the drain valve is not
operational.
Figure 9.1 -Hose Testing Hatch Covers
94
Limitations:
Hold must be empty of cargo
needs at least two crew to handle the
hose and nozzle
needs two surveyors, one monitoring the
hose on deck while the other is in the
hold with a powerful flashlight to locate
any leaks
water leaks that fall into the hold only
provide a general location of the leak so
the hatch covers must be opened to find
the exact location
disrupts cargo operations.
9.4 Air Test
* May not be permitted under
some
port
regulations.
Seals to be monitored are coated with a light
soap solution. The hatch covers, ventilators
and all accesses are closed and cleated. A
low air pressure is then applied to the hold.
Bubbles in the soap around the seals
indicate that air is passing and there is a
possibility of a leak.
Limitations:
Hold must be empty of cargo
must be carried out
in
daylight
must be carried out in dry conditions
disrupts cargo operations.

94. 9
1ht
s
~
9.5 Putty or Moulding
Clay Test
This test is usually carried out by hatch
cover manufacturers to determine alignment
and clearances. The rubber seal is first
removed. Putty or moulding clay is
positioned at regular intervals along the
length of the empty seal channel. The
covers are then closed and re-opened,
leaving a groove in the putty. This allows the
inspector to measure the bearing pad
steel-to-steel weardown together with any
misalignment, allowing repairs or
modifications to be carried out.
Limitations:
Must
be carried out in dry conditions
disrupts cargo operations.
Various Hatch Cover Testing Methods
'.
95

96. The Use of Ultrasound Testing Equipment, Principles and Operation of the Various Equipment Available on the Marke
10 The Use of
Ultrasound Testing
Equipment,
Principles and
Operation of the
Various Equipment
Available on the
Market
10.1 What is Ultrasound?
Ultrasounds are sounds that cannot be
heard
by the human ear, ie sounds with a
frequency above 20 kHz.
Ultrasounds have
a number
of specific characteristics that
make them
useful in industrial applications.
Ultrasounds can be precisely measured.
High frequency sounds are also more
directional than lower frequency sounds.
The principle has been known for some
time. If you fill an enclosed space with high
Leak
W/L--=:
frequency sound (outside the normal
detectable aural range), using a frequency
matched receiver, leaks in hatch covers or
hatch coamings will be detected from holes
of any size, the intensity of the received
sound signal being proportional to the size
of the hole. The level of signal received is
also inversely proportional to the distance
from the source. The signal may be
measured aurally or digitally and most sets
available on the market measure both to
varying accuracy.
In a large space, the intensity of the sound
will only be proportional if all areas of the
whole space are subject to the same amount
of noise. If there are any obstructions, eg
tweendecks, centre girders, the strength of
signal is significantly dissipated, or
attenuated. The signal is also reduced if it
has to bounce off many surfaces due to the
effect
of standing waves.
Ideally, the
ultrasound bulk generator must be placed in
the centre of the space (see Figure 10.1)
and preferably at mid height. This may be on
a centre girder or
in the
middle of the
tanktop. If there are tweendecks the
generator should by preference be placed
Double bottom tank P&S
Figure 10.1 -Generation of Ultrasound Inside a Hold
99

97. Hatch Covers -Operation, Testing and Maintenance
C/L
Main deck Hatch cover Hatch cover
.--~~~tre~~ .. ~
1 ~
~ ..... ' ........ ' I I \Jl"'"j
..... ~........ ' \I ' I / ,,-1'
'...... ....._~ ...\--"'-; I
' :.~~'L '1'1 I)
W/L - --, II"" ..... ~ ..J. I , ....... ../ 1f -
---' i'f' //'
~---- 'I', 1, 1~-1...tf
---'i '\I 1/''
--t'-l.u
1
0r-..r~
' µ; ~
"\. ~ I I ~/- <:._
Centre girder , ... '\llJY /,,;. _ 'ii'
Tanktop •
Figure 10.2 -Generation of Ultrasound Inside Twin Holds
on the tweendeck hatch. If there are centre
girders, each side
of the
hold should be
tested separately (see Figure 10.2). While it
is stated that the equipment may be used in
holds containing cargo, this is debatable as
the ultrasound could be absorbed by the
cargo. The equipment has been used with
coal and steel cargoes with no detrimental
effects. The equipment is also not
intrinsically safe.
With earlier equipment extraneous noise
was a problem, causing interference with the
received audible signal at the headphones,
eg arc welding, hydraulics, compressed air
100
Double drainage
channel
Hatch cover
I ~
Drain valve
Hatch Side And Ends
Locator block
Ultrasound
Cross Joint
Figure 10.3 -Passage of Ultrasound Through Double Drainage Sealing System

98. the
;,
r
The Use of Ultrasound Testing Equipment, Principles and Operation of the Various Equipment Available on the Market
leaks, etc. Later equipment appears to have
resolved most of these problems.
NOTE:
Ultrasound detection equipment is also
used for many other applications. It may
be used for watertight testing
of roro and
car carrier ramp doors {where access
is
available). The UE systems equipment is
particularly designed for general
engineering use. It is also suitable for
finding leaks in vessels, eg GRP,
aluminium and steel yachts, where it can
take only minutes to find a leak that would
otherwise take hours to find.
10.2 Advantages of
Ultrasound
Advantages:
Needs only one surveyor, one other
seaman needed to take the transmitter
down into the hold
all equipment and decks can remain dry
non-destructive
non-invasive
can
be used in
all weather conditions
non polluting
no need for cumbersome flashlights and
wellington boots
the equipment can be used
in empty
holds and holds containing cargo.
However, some bulk cargoes may absorb
the ultrasound signal, so the transmitter
must be placed as high and as centrally
as possible in a hold with cargo
ultrasound testing of hatch covers is
quicker than previous methods, taking
approximately 15-20 minutes per hatch
cover (if there are no leaks!)
it is sufficient to test the hatch covers
without cleating. If leaks are found, test
with cleats in place. If the leaks are still
apparent a report showing the nature and
extent
of the
leaks may be made
Figure 10.4 -SOT Equipment
Disadvantages:
Earlier equipment is bulky and must be
carried
in a medium sized suitcase, which
adds to the equipment carried by the
surveyor
some equipment has been found to be fragile, ie not robust
cannot be used
in sub-zero temperatures
may not be
intrinsically safe
disrupts cargo operations.
10.3 The Equipment
The basic equipment consists of an
ultrasound generator, which is placed in the
hold, and a receiver unit fitted with a
microphone to receive the emitted
ultrasound signals. Equipment varies in its
design
of generator, receiver and
microphone, and there may be
additional
enhancements.
There are a number
of types of equipment
currently in use. Some of the equipment is
not now available from manufacturers but
101

99. Hatch Covers -Operation, Testing and Maintenance
Figure 10.5 -Wylam Hill 'Portascanner' Equipment
102
Carry case
gun
Bulk generator
Figure 10.6 -UE Systems Ultraprobe 2000
Equipment
Figure 10.7 -UE Systems Ultraprobe 2000
Equipment in Use
might still be used by some survey
companies. The following is a list of
equipment in the chronological order that it
was developed.
The SOT 101 or 150 set consists of:
1. One SDT8 multitransmitter/generator unit
with 8 transducer heads, case and
carrying strap.
The
2. c
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4. F
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4. 0
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NOT

100. 00
lit
The Use of Ultrasound Testing Equipment, Principles and Operation of the Various Equipment Available on the Market
Reading 8 on 10 scale
=80% leak
Figure 10.8 -Closer View of UE Systems
Ultraprobe 2000 Equipment Reading
2. One SDT101 or SDT150 receiver set with
LED display and socket for headphones.
Receiver
microphone fitted to head of
receiver unit.
3.
One set headphones.
4. Foam lined Samsonite carrying case for
all equipment.
5. Instruction manual.
The Wylam Hill 'Portascanner' set consists of:
1. One bulk generator with 17 transducer
heads, ~ 2 x 1.5 volt C batteries and
carrying hook. Two permanent magnets
fitted to base.
2. One receiver set, 2 x PP3 batteries, LCD
display and socket for headphones and
microphone extension.
3. One set headphones.
4. One 3 feet long extension pole in two
pieces (screwed together) one end fitted
with the
sensor head and other with
cable
with jack plug to fit into the receiver unit.
5. Foam lined carrying case for the bulk
generator and one for the receiver unit
and headphones.
NOTE: This equipment is now marketed by
Coltraco.
The UE Systems Ultraprobe 2000 set
consists of:
1. One signal generator with one transducer
head.
2. One bulk generator with 4 transducer
heads.
Figure 10.9 -SDT Sherlog Equipment
Figure 10.10 -Sherlog Equipment
103

101. Hatch Covers -Operation, Testing and Maintenance
Figure 10.11 -Sherlog Equipment in Use
3. One receiver gun with linear display and
socket for headphones.
4.
One set heavy duty headphones.
5. One 3 feet long extension pole for
detecting vibration variations,
eg, bearings.
104
Figure 10.12 -Photograph of Class
Instrumentation 'CargoSafe' Equipment
Figure 10.13 -C ose~ e of CargoSafe
Transrr-
~e
6. Foam lined alum·n· .., ca ,·,,g case for
all equipment exce:)· • e generator.
7. Instruction manua
The SOT Sherlog TA ec ... ·p
1. 1 x Sherlog Ultrasor c De ector with
battery and rubber pro•ect on.
2. 1 x battery loader for aetector's battery;
240 V European pug.
3. 1 x Sherlog 8 Multi se >1g ultrasonic
transmitter with battery and leather
case.
4. 1 x spare battery for the
multi-transmitter.
5. 1 x battery
loader adapter for Sherlog-8.
6. 1 x battery loader for Sherlog-8., 240 V
European plug.
7. 1 x 820 mm flexible rod with a 10 mm
external sensor for the Sherlog detector.
8. 1 x headphone 130 dB.

102. Safe
for
1tor.
ts of:
l
tery;
c
og-8.
.ov
m
~ctor.
The Use of Ultrasound Testing Equipment, Principles and Operation of the Various Equipment Available on the Mar-e
9. 1 x cable RS232 Stewart -Sub 09
female; L 1,5m (for connection to PC).
10. 1 x 35' diskette with software
for data
transfer to
PC.
10.4 Miscellaneous
1. One 'Y' plug connector. 2. One shoulder
strap, for Sherlog detector and 1 for the
multi-transmitter.
3. Four precision
indicators for
Sherlog detector (threaded
tip, rubber tip, tubes).
2. One shoulder straps, for Sherlog detector
and 1 for the multi-transmitter.
3. Four precision indicators for
Sherlog
detector (threaded tip, rubber tip, tubes).
4. One screw driver for battery cover of
multi-transmitter.
5. One technical and user manual.
6. One Calibration Certificate.
7. One copy of the different Class Type
Approvals.
8. One carrying suitcase + foam inlay.
The ~lass Instrumentation 'CargoSafe'
equipment consists of:
1. One bulk generator with 13 transducer
heads.
2.
One receiver set with LCD display and
socket for headphones and
sensor
extension. Various other enhancements,
which include remote operation
of
on/off.
3. Carrying cases for both of the above
with shoulder straps.
4.
One set headphones that can be used
with a hard hat.
5.
One 3 feet long telescopic extension
pole and a 9" long flexible tube, one end
fitted with the
sensor head and other
with a
clip and locking device to fit to the
telescopic extension pole.
6. Foam lined carrying case for all
equipment.
7. Instruction manual.
8. Two packs AA rechargeable batteries.
9. Battery charger suitable for AA, PP3
and AAA batteries with adapter.
10. Copy of Class type approval certificate.
A full comparison of the equipment and its
performance is provided
at Appendix 2.
10.5 Comparison of the
Equipment
In September 1999, there having been no
comparison tests previously carried out, the
three sets
of equipment existing at that time
were tested by the author. The tests were
carried
out on a five year
old bulk carrier
with five MacGregor forward and aft folding
hydraulic
ram type hatch covers, known to
have
leaks. Independent observers were
present to ensure that the testing system
was fair.
The
results of these comparative
tests are provided in the first three columns
of Appendix 2. A comprehensive testing
scheme was carried out that also combined
transmitters with receivers from different
manufacturers.
As a consequence
of those findings and
representations to various bodies relating to
ergonomic design,
new equipment was
v
Bearing pads
r
i --..JL_ Bulk generator on
:_~ ~ II tanktop here
Figure 10.14-Diagram Showing Container
Hatch Cover Pontoon Arrangement
105

103. Hatch Covers -Operation, Testing and Maintenance
developed to suit the requirements of marine
surveyors carrying
out day-to-day hatch
cover testing.
SOT in conjunction with MacGregor
developed the Sherlog equipment, which
was initially marketed by MacGregor but is
now marketed directly by SOT. The
equipment is very similar to the previous
SDT150 equipment in a different colour with
the
sensor unit at the end of the extension pole, together with a sensor in the unit itself
and a microprocessor incorporating a
datalogging function.
As a consequence of the comparison test
findings, UE Systems were believed to be
co-operating with a UK company to develop
a bulk generator more appropriate for
marine use, but this has not yet materialised.
They were also reported to be developing an
extension
arm for ease of access.
UE have
also introduced a digital version of the
analogue Ultraprobe 2000 gun to the
market, the digital Ultraprobe 9000 gun.
Class Instrumentation Ltd, not previously in
the market,
who are makers of marine
measuring equipment, then
developed the
CargoSafe model for hatch cover testing.
The original prototype generator and
receiver were both comparatively small and
compact, the total weight of the unit being
1. 7 kg. The carry case was small to medium
size and capable of being carried in a hand
106
Wash
plate
Hold
Received
signal
100% here
(Generator on tanktop)
Cross Section Through Hatchcover
Figure 10.15 -Gap Between Centre and
Outboard Pontoons
carry bag. The difference in weight between
this and
other units was due to the use of
power saving
electronics and ANPP3
batteries, which lasted for at least 20 hours.
The bulk generator was small and light
enough to fit into a pocket and be carried
into and
out of
holds.
As a consequence of the above
developments, in January 2002 further tests
were carried
out using the
newly developed
Sherlog and the original prototype Class
Instrumentation equipment. Details of the
additional two sets of equipment are
summarised in the last two columns of
Appendix 2. The tests were carried out on a
6,000 TEU container vessel in Hong Kong
on 24th
January
2002. One thing that is
immediately noticeable is the difference in
weight between the two sets of kit, the
Sherlog case weighing around 7 kg, the
Class Instrumentation kit weighing 1.7 kg in
total. This can be attributed to the amount of
equipment included in the Sherlog case,
which includes two spare rechargeable
batteries and the two associated battery
chargers. It may also be as a result of the
more robust materials used in its
manufacture.
The container
vessel used for testing had
non-watertight hatch covers, consisting
of
three pontoon hatch covers abreast, ie, the
centre
panel is non-watertight, while the
50% reading ~
50% reading here , ~
Hatch roami ng Hatch<Dver
100% reading here
A
No 7 after hold
~ I Bulkhead
~
I
I
:(
I ,.
' I
I
/
Tank.top
0
Bulk generator
Double bottom tanks
Side Elevation Of Hold
Figure 10.16 -Comparison of Results at
Different Locations
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104. The Use of Ultrasound Testing Equipment, Principles and Operation of the Various Equipment Available on the Market
outer panels are almost watertight (see
Figure 10.14).
We tested the equipment in
the empty after part of No 7
hold as detailed
below. We calculated the hold volume to be
approximately 15,000 m
3
.
Each of the
bulk generators was placed in
turn at the centre point of the tanktop. Using
the Sherlog, Class Instrumentation
CargoSafe (Cl) and UE Systems Ultraprobe
2000 gun, we were able to compare the
signal strengths of the Sherlog and
CargoSafe bulk generators. Measurements
showed that the Sherlog bulk generator is
more powerful than the CargoSafe
generator, which gives out approximately
80% of the Sherlog power. The readings
taken inside the hold represented the 'Open
Hatch Value' (OHV).
As would be expected, measurements also
showed that the signal strength reduces with
distance from the generator. The amount
of steelwork also interferes with signal
strength, ie, staging, ladders, stringers,
frames, etc, which obstruct the signal
reflections, reducing the amount of
ultrasound in the space.
Both sets
of equip.ment are
supplied with
extension pieces with the microphone at the
outermost end, the Sherlog microphone
being slightly smaller than the Cl
microphone. The extension and small
microphone allow the user to measure the
signal in otherwise inaccessible locations.
We were therefore able to get the receiver
heads down into the non-watertight middle
panel joints as shown in Figures 10.14 and
10.15.
With the heads protruding through these
joints into the hold the signal, as would be
expected, was almost 100% of the
generated signal. As the heads were
withdrawn towards the upper edges
of the
hatch pontoons, the received
signal was
reduced by up to 50%. Similarly, a 50%
difference in the OHV and that taken at the
open access hatch was measured. The fact
that the reading taken at the open access
hatch and at the upper edges of the hatch
pontoons was the same, means that a hatch
cover leak measurement which is the same
as
an open access hatch reading indicates a 100% leak. This leads to some debate as to
whether taking
an
OHV with the hatch
covers open
is appropriate.
Some would
argue that if an open access hatch on the
upper deck can give a 100% leak into the
hold, then readings taken at the access
hatch should be used as the reference or
OHV value, ie erring on the side of safety.
Both receivers showed a base reading
of
10 dB as there is never a perfectly silent
environment. As before, the OHV is
measured first. On the CargoSafe
equipment, a note must be made of the
reading,
in this case it was 136. The
Sherlog
OHV was measured at 50.1, which could
then be entered into the receiver unit and
used as a base figure. Class Instrumentation
have since improved their equipment to
remove the 10 dB signal.
The newer Class Instrumentation Ltd
equipment also has the ability to convert the
OHV db value to a 100% figure with leaks
shown as a percentage reading.
A difference was noted
in readings taken at
leaks around the hatch cover bearing pads.
The Sherlog receiver recorded a higher leak
reading than the CargoSafe equipment. We
believe this to be due to the steelwork in the
vicinity
of the pads causing interference, the Sherlog bulk generator clearly having
sufficient power to overcome this. Cl have
since improved the output of the generator
to overcome this problem.
Both LCD displays are relatively stable but
will vary depending on the stability of the
sensor,
ie, when
held perfectly still, the
reading is totally stable. The Cl CargoSafe
Mark II display showed only the measured
decibel reading. It now displays both decibel
and percentage readings. The Sherlog LCD
display has far more information on the
screen, there also being a bar type display
to show the percentage OHV reading. The
107

105. Hatch Covers -Operation, Testing and Maintenance
Sherlog receiver allows for maximum or
continuous readings to be shown, the former
being a more stable version of the latter.
With the datalogging facility, readings can be
entered into the memory
of the unit and may
be identified
by text entries
similar to that of
a mobile telephone. Consequently, the latter
can take some time and will depend on the
skill and familiarity of the user. The
information recorded can be downloaded to
a PC and tabulated. However, as with all
other models, the user still has to draw a
diagram of the hatch cover and
add the locations and size of leaks.
10.6 Hatch Cover Testing
Protocols and
Procedures
There are many and different clients on
whose behalf a marine surveyor will be
required to carry out hatch cover
testing.
Whoever the
client, it is advisable to have a
letter of appointment to show to any
authorities requiring such evidence.
Before leaving base, or your hotel, to travel
to the vessel, it is advisable to ensure that all
equipment is operational. It is possible to
inadvertently leave some equipment
switched on, draining batteries overnight.
The equipment that has easily obtained
batteries has a clear advantage in this
respect, unless you carry spare charged
batteries.
1
() ~ ~· Prntnrnlc:::
On boarding, advise the Master of the
reason for your visit and who appointed
you. If necessary, show him a copy of
your appointment letter, fax or email
• was the Master advised of your visit? If
not, report this to your principals/client
later. If he refuses you access, report it
immediately
explain the reason for your survey
108
explain the ultrasound testing method
and, if he has not experienced the
procedure previously, show him how the
equipment works using his refrigerator,
ie bulk generator inside the fridge, receiver
used to detect leaks around the magnetic
seal
invite the Chief Officer/Master to witness
the tests when carried out and give him
the opportunity to operate the equipment.
inform the Master and attending officer
about specific issues, ie pass/fail criteria
be flexible and patient. Very often it is not
possible to start at hatch cover No 1 and
work aft. You may have to fit in with the
stevedore's loading or discharge
schedule. It may also be necessary to
work around a shipyard's repair schedule
explain why independent testing methods
are different from Class methods and
requirements. (See Class approval, later)
ensure that the hold has been ventilated
before allowing anybody to enter the hold.
ensure that ventilation is continued if
there
is cargo present.
Follow entry into
enclosed spaces' procedures
draw the attending officer's attention to
defects/leaks and allow him to hear
and/or sight the leak signal
explain what the leak signals indicate, eg,
small gap in seal, corroded compression
bar, etc
compliment the attending officer on good
points before referring to poor or
defective items
advise the attending officer to mark the
exact position
of
leaks, eg with paint or
chalk, to allow repairs to be carried out
later
explain defects mentioned in the
deficiency list, what is wrong and why,
and what is good practice
do not make recommendations about
repairs unless the principals have asked
you to do so

106. The Use of Ultrasound Testing Equipment, Principles and Operation of the Various Equipment Available on the Market
advise the Master if a follow-up survey is
needed and likely to be carried out
emphasise the importance
of carrying
out proper repairs instead
of quick or
improper temporary repairs
make
clear agreements about date/time
of next inspection and which items will be
tested if you have been requested by
your client to ensure that defects are
rectified.
NOTE:
Treat the Owners' representatives, the
Master, officers and crew, with due
respect. You are not onboard the vessel
as a policeman but as an auditor. You will
find them to be more co-operative when
you mention that the tests are being
carried out to protect their lives, the ship
and the cargo.
-t n a '} 0 ... ,...,...,...,...1, .... ,...,.~
On most occasions, the surveyor will have to
fit hatch cover
testing
in with the
vessel's
operations. It may be possible to carry out
testing on only one or two hatch covers and
then have to wait for others to become
available. It may only be possible to carry
out the testing wh'ile stevedores are taking
meal breaks. It will be up to the surveyor to
co-operate with the Master and Chief Officer
to work out the best programme.
If hatch cover testing
is part of a
general
condition survey, eg, P&I Club or Charterer's
survey, the surveyor will need to establish
when it will be possible to carry out the
hatch cover testing. It is advisable to carry
out the testing first so that any defects found
can
be rectified and re-testing can be carried
out before the surveyor
leaves the vessel. If
possible, and to prevent duplication, it may
also be advisable to carry out the testing in
conjunction with a Class surveyor, who might
also be required to carry out testing for
Loadline Certificate renewal purposes. Class
generally use hose testing only as they do
not carry any ultrasound equipment. They
are generally content to witness the
independent surveyor's ultrasound testing
and, if any defects are found, to carry out
hose tests
in the defect
locations only.
The surveyor will need another crew
member to assist with taking the transmitter
unit down into the hold. There will also need
to be a senior officer to witness the tests.
Establish a procedure with the officer and
crew member who will assist:
Ensure that the attending officer present
and the crew member who will enter the
hold have a walkie talkie VHF set each.
Test the VHF sets before proceeding.
Insist that radio silence be observed
when instructed
ensure that the holds have been
ventilated and that the atmosphere has
been tested and certified safe for entry
show the crew member who will take the
transmitter unit (in the off mode) into the
hold how to switch it on and off
instruct the crew member to place the
transmitter
in the centre of the tweendeck
hatch, or tanktop if there
is no
tweendeck, and switch
on when
told by
the attending officer on the walkie talkie
instruct the crew member to remain in the
hold until instructed to switch off the
transmitter unit and come out
of the
hold.
This should be approximately
15-20 minutes
instruct the man
in the
hold and officer on
deck that VHF is not to be used and radio
silence should be observed until you have
completed the ultrasound test. If the
attending officer follows you around the
hatch cover you can check that this
is
happening
when the crew member has switched
on
the transmitter unit, test for
Open Hatch
Value (OHV) at the hold access hatch. If
required, calibrate the equipment
dog the access hatch shut as stray
ultrasound can affect results
start the hatch cover testing at the
nearest end or side. For the best results,
109

107. Hatch Covers -Operation, Testing and Maintenance
test the side seals with the sensor about
4-8" (100-200 mm) away from the hatch
cover lower edge. When leaks are found,
record them
in your note book (see
reporting
later) and allow the attending
officer to see and hear the leak. After the
side seals you will need to do the cross
joints. The size
of the gaps between
panels and the size of the receiver head
will determine whether you will be able to
get the receiver down to the seal. If this is
not possible, you will need to slowly scan
the gap from end to end. The equipment
is sensitive enough to pick up the
slightest leak. The extension pieces also
allow the user to carry out all tests from
the
top
of the hatch cover
if you are not receiving any
signal during
testing,
ie there appear to be no
leaks, it
may be advisable to return to the access
hatch periodically to ensure that the
transmitter
is
still switched on, as some
unscrupulous officers and owners'
representatives may instruct the seaman
in the
hold to switch off the transmitter
once the access hatch has been closed.
(The CargoSafe equipment has a remote
operating switch
on the receiver so that
the surveyor can operate the transmitter
from the deck.
It also indicates whether
the transmitter
is switched on or off.)
if
leaks have been found, it is advisable to
open the hatch covers to confirm the
reason for the leaks. Marking the leaks
during testing will make finding them a lot
easier
there will be times when the surveyor will
find no leaks on the hatch covers but will
still be able to hear and see a measured
signal on the equipment. Don't be fooled.
The equipment never lies. There is clearly
a leak somewhere and it is up to the
surveyor to find
it. The
leak may be
coming from:
110
the hatch coamings -leaks from
corrosion wastage holes or gas
sampling ports
• hold ventilators -Corrosion holes
near to deck level
• hold ventilators -From bulk carrier
ballast tank ventilators which may be
immediately adjacent to the
hatch coaming
• hold access hatch -Not dogged
down correctly, seal leaking or
hatchway corroded/wasted and holed
• main deck -Corrosion wastage
holes
• mast house -Corrosion wastage
holes or access hatch not closed
inside mast house and external door
left open.
r.nnrting
Pass/fail criteria:
0 dB = hatch cover is leak.tight
1 to 1 o·% of OHV = weathertight
Above 10% of OHV = NOT weathertight
When reporting test results, simple diagrams
are the best way to indicate leaks (see
Figures 10.17 and 10.18).
Trying to explain the findings with words
alone can become cumbersome and open to
misinterpretation. Figure 10.17 shows a
suggested
reporting method for
Coltraco
equipment while Figure 10.18 shows that for
the SOT, Class Instrumentation and UE
Systems equipment, which includes the
instrument readings, based
on a
10 scale for
a 100% leak, ie the figure 3 represents a
30% leak. As may be seen, a general leak
over a length of hatch cover seal is shown
together with point leaks. Once a user is
skilled in use of the equipment, it is possible
to detect the nature of the leak, ie corroded
hatch coaming
bar, grooved
seal or gap in a
seal joint.
The surveyor should accurately report his
findings to his principals. Some substandard
and unscrupulous operators may pressure
the surveyor not to report non-watertight or

108. The Use of Ultrasound Testing Equipment, Principles and Operation of the Various Equipment Available on the Market
weathertight hatch covers. It is in nobody's
interest to lie or hide findings. It is in
everybody's interest to accurately report the
findings so that the safety of the vessel,
cargo and her crew can be protected. The
surveyor should also report,
in confidence,
to his principals if he has been pressured
in
such a way. The surveyor
should always
bear
in mind that another surveyor may follow at some time later to carry out the
same survey, particularly if the client
suspects collusion with owners.
p
p
F
C/J
C/J
1~-----------1'
C/J 'P >'>'>'>'>'>'>' P\.
A
Legend:
C/J = Cr CBS j]in I
X = f-BavyLeal
/ = Light lea!
s
Figure 10.17 -Diagram Showing Test
Results for Wylam Hill or Coltraco
Equipment
F
Legeoo:
CIJ = O-Oss Joi rt
7.5
X = Hea~y Leak
CIJ / =light leak
10.0
9.0
C/J
s
C/J 8.5
2.5
3.0 -4.0
90
A
8.0
Figure 10.18 -Diagram Showing Test
Results for SDT, Class Instrumentation and
UE Systems Equipment
'.
111

110. Class Approval of Ultrasound Testing Equipment and Operators
11 Class Approval of
Ultrasound Testing
Equipment and
Operators
11.1
Class Approval
............ :_ ... _.,..,#
When ultrasound testing equipment was first
developed by SOT in the 1980s, its accuracy
and usefulness were unknown. It took a lot
of testing and calibration by surveyors from
Sparks & Co NV of Belgium to confirm its
accuracy and suitability for purpose. In the
early 1990s, the P&I Clubs and some
Charterers became interested
in its use as it would clearly save them time and money in
the short term, with a reduction in claims in
the longer term. However, about this time,
Wylam Hill (WH) were marketing the
Portascanner model. The lower cost of the
WH equipment made it popular with many
independent surveyors. Consequently, it was
suggested that ultrasound testing equipment
should have Class. approval.
SOT then applied for Class approval and
obtained DNV approval, 'user approved only'
for the SDT101, SDT13(A) and SDT150
units, which are no longer in production. This
meant that the equipment was only
approved for hatch cover testing where the
user had received special training. The SOT
equipment was then the only Class
approved equipment and so set the standard
for other equipment.
Wylam Hill attempted to obtain Class
approval but were informed that there was
little chance of this while the LCD display
was unstable and did not accurately
measure the decibel level. Wylam Hill later
became Coltraco.
To date
(2007), the
Coltraco equipment still does not have Class
approval.
While the UE Systems Ultraprobe 2000
equipment was intended for more general
engineering applications, it was also suitable
for hatch cover testing for smaller vessels,
the generator being too small for larger
ships. UE Systems obtained DNV and
ASTM E1002-93 type approval for general
engineering use. ABS type approval for
hatch cover
testing was obtained
in 1994.
During
2000, the Sherlog equipment was
marketed by MacGregor and SOT. The
equipment received type approval from LR
and the Hellenic Register. Type approval is
valid for five years.
The Class instrumentation CargoSafe
equipment has since received ABS type
approval for their equipment and is endorsed
by a number of P&I Clubs.
...... '1 ') (""°' --.l:.C:,..,..,+;,... ....
So what does Class approval mean? It
would appear that there are a number of
types of approval relating to ultrasound
equipment:
1. Certificate
of design
approval by a
Classification Society.
2. Type approval by a Classification
Society.
3. Type approval by a Classification
Society when used by a properly trained
operator.
4. Type approval
of the equipment when
used by a service
supplier to a
Classification Society for the issue of
statutory certificates.
1. Certificate of design approval by a
Classification Society.
The ABS Certificate of design approval
states that the Society assessed the design
plans and data for the product. The
assessment shows the degree
of
compliance the design exhibits
applicable
sections of the rules. The assessment does
not waive
unit certification or classification
procedures required
by the rules for
115

111. Hatch Covers -Operation, Testing and Maintenance
products to be installed in ABS classed
vessels or facilities. The certificate does not
reflect that the product is Type Approved.
The scope and limitations
of this
assessment are detailed on the pages
attached to the certificate. The certificate
remains
valid for 5 years from the date
of
issue or
until the rules or specifications used
in the assessment are revised (whichever
occurs first).
2. Type
approval by a Classification
Society
The LR Type Approval Certificate for the
Sherlog equipment states:
"This is to certify that the undernoted
product
has been tested with satisfactory
results
in accordance with the relevant
requirements
of the LR Type Approval
System." ...
Application:-"Verification of marine,
offshore and industrial weather tightness
of hatch covers, doors, ramps and windows." For use in environmental
categories ENV1
and ENV2 as described
in LR
Test Specification No 1:
1996."
The ENV1 and ENV2 categories relate to
the environments
in which they
should or
should not be used, as defined by LR Test
Specification No
1: 1996. Consequently, the
approval tests are designed to
reflect these
conditions.
Information on test approval can be obtained
from the LR Type Approval System
Procedure TA96, which outlines the approval
procedure. This includes information on the
various temperature, environmental and
chemical tests to which the equipment will
be subjected to obtain approval.
The manufacturing company's QC Program
must also be submitted for vetting and
approval, together with the company's
IS09000 Documentation and Procedures.
116
3. Type approval by a Classification
Society when used by a properly
trained operator
The Hellenic Register Type Approval
Certificate for the Sherlog equipment states:
''This
is to certify that the following
product
has been evaluated in
accordance with the provisions
of the
Type Approval
System of this society with
satisfactory results and
is TYPE
APPROVED subject to the conditions
of
this system with particulars ...
"Approval Conditions: . ..
• Operation of the above equipment
should be performed by a skillful
operator specially trained.
I have been unable to find any reference to
the appropriate training courses required to
bring a surveyor up to the.required standard
to make him/her 'a skillful operator, specially
trained'. It is assumed that when applying for
certification, the equipment manufacturer
will have to submit full details of the courses
offered to bring the operator up to the
required standard. There are currently two
companies offering such courses, SDT and
Class Instrumentation, the former currently
being Class approved while the latter is in
the process of applying for Class approval.
4. Type approval of the equipment
when used by a service supplier to a
Classification Society for the issue
of statutory certificates.
The section of the 'IACS Requirements
concerning Survey and Certification' relating
to approval of equipment
is
Section UR Z17
(1997, Rev. 1 June 1999, Rev 2 November
1999) entitled 'Procedural Requirements for
Service Suppliers', which sets out basic
standards for qualifying service suppliers.
The Requirements contents are:
1. General
2. Objective
3. Application

112. :;:
th
1r
Class Approval of Ultrasound Testing Equipment and Operators
4. Procedure for Approval and Certification
5. Certification
6. Information of Alterations to the Certified
Service Operation System
7. Cancellation of Approval
8. Existing Approvals
Annex
1. Special Requirements for Various
Categories
of Service Suppliers.
Section 3.11 of the Z17 standard defines the
categories
of service
suppliers, ie, firms
engaging in:
• Thickness measurement on ships
• tightness testing of hatches with
ultrasonic equipment
• in-water survey of ships and mobile
offshore units
• examination of Rora ship's bow, stern
side and inner doors.
Section 4 of the Z17 standard defines the
procedure for
Approval and Certification,
ie, submission of documents:
• Outline of. company, eg, organisation
and management structure, including
subsidiaries
to be included on the
approval/ certification
• list of nominated agents
• experience of the company in the
specific service area
• list of operators/technicians/inspectors
documenting training and experience
within the relevant service area, and
qualifications according
to recognised
national, international
or industry
standards, as relevant
• description of equipment used for the
particular service for which approval is
sought
• a guide for operators of such
equipment
• training programmes for
operators/technicians/ inspectors
• check-lists and record formats for
recording results
of the service
referred
to in Section 1
• evidence of approval/acceptance by
other bodies,
if any
• information on the other activities
which may present
a
conflict of
interest
• record of customer claims and of
corrective actions requested by
certification bodies
• where relevant, list and documentation
of licenses granted by equipment's
manufacturer.
Operators of
ultrasound hatch cover testing
equipment, used for Class statutory
certificate issuance, must fulfill the
requirements
of this standard. The
equipment to be used must
also have Class
type approval.
In this context, it is interesting to note that in
practice, when surveying a vessel for a
Loadline Certificate, Class would normally
carry out a hose test. If ultrasound is to be
used, it
is the owner who requests it. Generally, Class do not carry such
equipment and a subcontractor who meets
the above requirements must be used. The
Class Societies supply lists of approved
companies used for this purpose.
IACS rules relating to the use of Class
approved subcontractors are summarised:
1. Acceptance of Statutory Service
Suppliers:
The /ACS Unified Requirement
UR
Z17.1.2 states:
"Where such services are used by
Surveyors
in making decisions affecting
statutory certifications, the firms are
subject
to approval by the Society where
the Society is so authorized by the
relevant flag Administration. For such
services the Society may accept
approvals done by the flag Administration
117

113. Hatch Covers -Operation, Testing and Maintenance
itself or duly authorized organizations on
behalf of the flag Administration."
In other words, where the /ACS Member
Society is authorized by the flag
Administration
to carry out statutory
surveys and that flag Administration has
approved the supplier, the Society
may
accept that approval. The Society may
also accept approval
of another
/ACS
Member Society when both parties are
authorized to conduct statutory surveys
on behalf
of an Administration. However,
whether to accept the approval
of other
Members is always subject to individual
Societies' consideration on a case by
case basis taking into account paragraph
1.2
of
Z17.
118
2. Acceptance of Classification Service
Suppliers:
It is the prerogative
of the Member
Society classing the ship
to choose to
accept
or not the certification of a service
supplier by another Society, in so far as
classification is concerned. No change is
anticipated in the near future in the
fundamental issue and policy in this
regard.
It is suggested that service suppliers
contact the relevant Classification
Societies to determine whether
or to what
extent those Societies are prepared
to
accept certification carried out by other
Member Societies,
or to what extent the
Society is amenable to having another
Society, with which it may have a bilateral
agreement, attend on its behalf when
certifying a classification related service
supplier.
·
The above requirements ensure that one
Class approved subcontractor meets the
requirements
of another
Class Society and
that a Flag State approved supplier can be
accepted
by a Classification Society.
Before you
all rush out to obtain approved
subcontractor status, be warned. Class do
not directly appoint independent surveyors
as subcontractors. This is usually restricted
to MacGregor or some small companies in
remote locations.

115. 12 Common Defects
Found when Hatch
Cover Testing
The most common defect found on hatch
covers is heavily grooved and hardened
seals. This
is caused by corroded, wasted or
heavily worn steel to steel cross channel or
side/end bearing pads.
In the event of lack
of full contact between the seal and
compression bar a weak to medium signal
will
be heard along the
full length of the
affected seal.
Worn and misaligned wheels can cause
misalignment
of cover panels with resulting
damage to rubber seals, which can be torn
or creased. The ultrasound test will give
intermittent signals
of varying intensity
depending on the extent
of the damage to
the seal.
Figure 12.1 -Heavily Grooved and
Hardened Hatch Cover
Seals
Common Defects Found when Hatch Cover Testing
Figure 12.2 -Corroded and Wasted Bearing
Pad Showing Lack of Contact
Figure 12.3 -Combination
of Heavily Worn
Bearing Pads Resulting in a Heavily
Grooved
Seal. Note: Uneven Compression
Bar Due to Poor Repairs and Damaged
Inner Drain Channel Edge
121

116. Hatch Covers -Operation, Testing and Maintenance
122
Figure 12.4 -Severely Damaged Seal
Fig 12.5 -Severely Grooved and
Damaged Seal
Figure 12.6 -Damaged Seal Due to
Worn Roller
Figure 12.7 -Section of Seal Missing and
Poor Butting
of
Seal Joint
Figure 12.8 -Severely Corroded and
Wasted Compression Bar and Inner
Drain Channel Edge

117. Poor repairs to seals, eg not butting up
correctly or misaligned with adjacent seal
sections, will give a significant localised or
point signal when using ultrasound testing.
In Figure 12.7, the missing section of seal
would give a 100% reading over the length
of missing seal, with a more localised high
reading where the seal is not correctly
butted together.
In Figure 12.8 a signal of 0 to 10% was
measured. However, when opened it
was clear that any water passing the rubber
seals would have entered the hold due to the
severely corroded and wasted inner drain
channel edge. For this reason, hatch covers
should always be opened after testing to
check the compression
bar,
seal and inner
drain channel condition.
Heavily corroded and wasted compression
bars will give medium to high signals with
varying intensity due to the uneven wastage,
which results in varying contact between the
seal and the compression bar.
One of the most common areas for leaks is
at the side of a cross joint, where the seal is
required to meet il")"three different directions,
ie forward, aft and inboard. The reason for
this
is the
difficult configuration that is
required.
The surveyor may find different forms
of a
defective face
seal, as shown in Figures
12.9 to 12.14, where varying signal intensity
will be received depending on the extent of
damage of the seal. The same will apply
where the face seal compression bar is
damaged, as shown in Figure 12.11.
Common Defects Found when Hatch Cover Testing
Figure 12.9 -Damage to Omega System
Seal Adjacent to the Hatch Cover Panel Side
Fig 12.10 -Damaged Hatch Cover Face
Seal. Note Lack of Complete Contact as
Indicated by the Black Mark
Figure 12.11 -Damaged Hatch Cover Face
Compression Bar
123

118. Hatch Covers -Operation, Testing and Maintenance
124
Figure 12.12 -Rubber Seal and Damaged
Seal Channel with Corroded I Wasted
Bearing
Pad
Figure 12.14 -
Incorrectly Repaired and
Heavily Grooved I Hardened Rubber Seal
Figure 12.13 -Heavily Grooved I Hardened
Rubber Seal with Poor Repair Leaving a
Gap
Figure 12.15 -Severely Corroded and
Wasted Coaming Drain Pipe Rendering the
Non-Return Valve Redundant

120. 13 Repairs to Hatch
Covers
If leaks have been found during testing and
defects confirmed with the hatch covers
open, it will be possible to identify repairs
needed. However, as stated earlier, do not
make recommendations about repairs
unless Principals have asked you to do so.
The ship's officers should know what is
required.
Repairs are not usually the responsibility of
marine surveyors. However, some
independent surveyors may be requested to
act as Superintendent and supervise such
repairs.
Repairs can range from simple seal repairs
to major structural repairs to the cover
panels. Damage and repairs should be
taken
on a case by case basis. The
following
are brief and general guidelines.
Heavy grooving
of rubber seals is often
caused by heavily corroded and wasted
bearing pads. Before seals are
rene"'(ed the
bearing pads should be repaired or renewed
so that they are set to the correct height. If
the ship has no access to skilled shoreside
labour who can renew the pads, the crew
can make temporary repairs. These can be
carried out
by building up the pads with
weld
and then grinding them down to the correct
height.
Rubber seals can then be renewed provided
the seal channel is
in good condition. When
renewing seal lengths, the
seal channel
should be thoroughly cleaned out and
coated with compatible anti-corrosive paint,
together with the appropriate adhesive.
If possible, the full length of the seal should
be renewed,
ie cross joint, side or end.
If
this is not possible then a minimum of
1 metre length should be renewed. Where
the old and new seals butt up against each
other, arrangements should be made for the
Repairs to Hatch Covers
Figure
13.1 a -
Seal Channel Cleaned and
Painted Ready for New Seal
Figure 13.1 b -Rubber Seal Glued and
Ready
for Fitting
Scarf insert
Scarf insert
Old rubber with
•
permanent
Side Elevation End Elevation
Figure 13.1 c -Diagram Showing Use of
Scarf in Hatch Cover Seal
two to be of the same height. This can be
achieved
by means of scarf inserts or
packi
ng (see Figure 13.1 c). Corner joints
should be renewed before straight lengths.
127

121. Hatch Covers -Operation, Testing and Maintenance
128
Figure 13.2 -Severely Corroded and
Wasted Cover Panel Wheel
Figure 13.3 -Compression Bar Showing
Wear Where Rubber Seal is Chafing Due
to Severely Corroded and Wasted Cover
Panel Wheel
Where there is no spare packing rubber
available, existing rubber may be re-used
with packing rubber
of 5 or
10 mm thickness
to back up the seal and raise it to improve
compression. Sealing rubber is re-inserted
to the channel using wooden mallets. They
should be properly inserted and fitted before
the hatch covers are closed.
Compression bars are exposed to the
elements for much of their life and, unless
well maintained, will often be found to be
heavily corroded and wasted. Like rubber
seals, the full length of the compression bar
should be renewed completely, ensuring that
it
is of the same dimensions as the
original
design. If this is to be carried out in a
shipyard, it is advisable to renew the top
edge
of the compression bar with a
stainless
steel rod to reduce further corrosion
wastage, again ensuring ~hat the
modifications result in the original
compression bar dimensions. The original
steel part of the compression bar can be
repainted while the stainless steel bar is left
untreated.
Cross joint seals may become misaligned
because of worn face compression bars and
by worn panel hinges. Both should be
checked and renewed where necessary
before renewing the face seal.
Hatch wheels can become corroded and
wasted. This can cause lowering of the
covers when operating, causing
consequential damage to seals.
Wheels should be maintained in good
condition and regularly greased. If they are
to be renewed, they must be renewed to
original specifications.
Corroded and wasted cleats should be
renewed completely. Quick acting cleat
rubber washers can be renewed where
necessary, but the source
of the damage should be investigated and rectified to
prevent further damage.

122. Figure 13.4 -Hatch Cover Panel Repairs
in Progress. Incorrect Cropping of all Top
Panels Resulted in Heavy Warping of
the Covers
Corroded and wasted panels and seal
channels will need cropping and renewing.
Any hot work
on hatch covers has to be
carried out very
carefully. Hot work on only
one side of a cover can cause irreversible
distortion and misalignment. In the case of
repairs to top and side panels the covers
should be positioned on jigs to ensure that
they are flat and level. Heavy concrete
weights should be positioned around the top
panels before any cropping takes place.
Panels should not be removed from one side
only. They should be simultaneously taken
from opposite positions working towards the
centre. Alternate panels may also be
renewed to prevent
distortion.
Some box
type hatch covers are filled with inert gas to
reduce corrosion. When repairs are
completed the cover panels should be
re-inerted internally. This is achieved by
inserting special tablets inside, available
from the hatch cover manufacturers, before
welding the space shut.
If the whole seal channel around ends and
sides is to be cropped and renewed, the
same procedure as above should be
followed, cropping from opposite sides and
corresponding locations simultaneously.
Repairs to Hatch Covers
Figure 13.5 -Hatch Cover Panel Repairs
in Progress. Incorrect Cropping of Some
Top Panels Resulted in Heavy Warping of
the Covers
Heavily corroded coaming bar trackways will
also need to be cropped and renewed.
Again, alternate sections should be renewed
to reduce the possibility of deformation. The
new material should be substantial enough
to ensure original strength.
129

124. Case Study 1
CaSf Hatch covers leaking in gale force
winds
Date July 2005
i:l".lrlrnro11nrl lnfnrm".l+i'ln:
The vessel was built in 2001
the vessel has 7 holds
deadweight 75,000 MT.
,..,...!~---· ·-....!·
In June 2005 the vessel left the port of
Necochea loaded with 57,800 MIT of
Soybeans in bulk, arriving at the port of
Longkou eight days later.
During the voyage, the vessel encountered
very strong winds
of force 8-9 and occasionally storm force 10 and high/very
high seas and swell. The vessel was taking
green water over the weather deck during
this period
of bad weather.
When the surveyor inspected the
vessel, the
wet damaged cargo had been discharged
separately and transferred to two
warehouses
in the port area. The wet
Figure
CS1 .1 -The Hatch Securing
Arrangement Onboard
Case Studies
damaged cargo was inspected in the
warehouse with the Owners' representative
and it
was found that the cargo
in question
was stored
in three
piles in the warehouse.
One of the 3 piles was found to be wet and
damaged (sodden), while the other two piles
were noted to have only some slightly wet
affected cargo
on the surface, with most of it
in a
normal sound condition.
Figure CS1 .2 -Damp Soy Bean Adhering to
the Hatch Coaming
It was estimated that 40 MT of the cargo
was wet damaged
in
total, but that sound
cargo had been mixed with the wet
damaged cargo.
Figure
CS1 .3 -Soy Bean in the Warehouse
133

125. Hatch Covers -Operation, Testing and Maintenance
The steel hatchcovers were of the split
type that are side rolling when opened
the panels of the hatch covers were of
the box construction type and the top was
flat. Rubber was embedded under four
sides around the panel and seemed to be
in normal condition
the operating system
of the hatch cover
was
hydraulic motor driven with rack and
pinion to split the panel, which appeared
in good condition
the cross joint compression bars on the
top plating of No.3 & 5 holds seemed not
to be compressing as traces
of rust were
found on the
bolts
the hatch coaming was equipped with
compression bars and water baffle and
four stopper blocks on the port and
starboard sides. Six drain holes were
located on the drain channel in way of the
4 corners and
at the
middle of the port
and starboard side. In total, 16 quick
acting cleats were equipped on the
circumference
of the hatch coaming
while
an additional 4 screw cleats were on
each
of the starboard and port sides to
provide further compression to the hatch
covers
Figure
CS1 .4 -The Opened Hatch Cover
134
the packing rubber was of watertight
seals and a backing strip, which were
compressed by the compression bar on
the hatch coaming to build up the
watertightness
of the hatch covers
the coaming compression bars were
ordinary
steel flat bars.
the transversal/cross joint compression
bars were ordinary steel flat bars
the bearing pad was steel-to-steel contact
the peripheral/perimeter cleating system
was a standard quick acting cleat, 16 for
each hold, and 8 additional screw type
cleats on port and starboard sides
the cross
joint securing device was cross
joint
bolts. These were partly rusted on
the surface
Figure
CS1 .5 -View From Below the
Opened Hatch Cover Looking Back to the
Cargo Hold
coaming drain channels were located on
the hatch coamings and six drain pipes
non-return valves were equipped on the
port and starboard side hatch coaming
of
each cargo
hold. Some drain pipes were
blocked by soybeans
the hydraulic equipment, consisting of
hydraulically operated cylinders/jacks and
motors, were noted to be
in good operational condition.

126. :ict
n
1r
;s
1e
n
of
e
nd
()hccrv~tion~·
1. There was no sign of sealing tape having
been used for hatch covers on this
voyage. However, it was noted that
residue from sealing tapes remained on
the hatch cover
of No.3, which had been
painted
in the same colour as the hatch
covers, suggesting that it had been used
on the previous voyage.
2.
It was noted that there were 3 drain pipes
on each
of the two sides of the hatch
coaming (starboard and port side)
of
each hold.
3. Apparent water traces could be found on
the hatch coamings
of holds No.2, 3, 5 &
6, irregularly on the peripheral of the
hatch coaming.
4.
One drainpipe on the portside and
another one on starboard side
of the
hatch coaming
of No.2 Hold were
blocked with soybeans. From their
appearance it is considered that they had
been there during the voyage.
5. With respect to Hold No.3, it was found
that two drain pipes under the drain
channel on the starboard .side, and one
on the
port side, were
also blocked with
soybeans, suggesting that the drain pipe
function would have been affected during
the voyage.
6. A similar situation was observed on the
hatch coaming
of Hold No.5, where two
drain pipes on the starboard side and one
on the port side were noted with
soybeans blocking the drain channel.
7. This was
also the case on the
hatchcoaming
of Hold No.6, where it was
noted that two drain pipes on the portside
were blocked with soybeans.
Case Studies
r"
"''
The vessel had been well and reasonably
maintained, with the hatch cover system and
other cargo-worthiness related areas
in
good condition. As per the
allegations made
by the ship's crew, the vessel experienced
very bad weather during the voyage and
water penetrated into the drain channel
through the sealing surface
of the coaming
and rubber packing due to
flexing of the ship
under pressure. The water baffle plates
appeared
in very good condition, without
any sign
of
local damage or wastage, but
when the ship was rolling or pitching the
water
in the drain channel would have
leaked into the holds, particularly when
some
of the drain pipes appeared to have
been blocked during the voyage (this
probably happened during the loading
operation). There were no documents to
support the
allegation of bad weather and
there was no opportunity to inspect the deck
log books.
The Master
of the vessel was asked if any
hose tests to the hatch covers were
conducted before the loading operation, and
were advised that no such tests were
conducted at the loading port.
The vessel completed the discharge and
sailed without any delay on the basis that
the owner's club
(SKULD) set up security to
the amount
of
US$100,000.
Reproduced through the courtesy of
SKULD
135

127. Case Study 2
Casi Leaking hatch covers -Damaged
steel coils cargo
Date Feb 2007
p".'.ll""l.rarot Jnrl I nfnrm~tinn·
The vessel was built in Ukraine in 1993
the Master and crew joined the ship
in
November
2006 as it was delivered to the
present owner, prior to the
commencement
of
loading operations in
Dalian
the vessel has 8 holds
the last dry-docking was March 2006.
l""Vrtt" ""'.
A surveyor attended the vessel at the Port of
New Orleans, Louisiana and Tampa, Florida,
to survey a cargo of cold rolled coils and
galvanized steel sheets.
On this voyage the vessel had carried only
about 75% of its total capacity of
52,245 tons. After discharge of the Tampa
cargo the vessel was to proceed to load a
full cargo °of bulk fertilizer destined for
China.
Figure
CS2.1 -Attending at New Orleans
Case Studies
On arrival onboard the general impression
as to the condition and overall level of
maintenance was fairly good. However,
signs
of prior
neglect and/or lack of
maintenance were evident in the hatch cover
arrangements.
.......... r"' rli+;,.......,..
The hatch cover panels had very recently
been sand-blasted and repainted. However,
there was
an advanced stage of (prior and
present) rust decay and severe wastage of
the
internals and the framing of the hatch
cover panels, grain doors and ventilation
cowl seals, which were in an unacceptable
condition.
The steel compression bars on top of the
hatch coamings for the hatch covers
of the
four
holds surveyed were in various stages
of 'disintegration'. The degree and severity
Figure CS2.2 -Hatch Coaming
137

128. Hatch Covers -Operation, Testing and Maintenance
of the rust had reached a point where the
steel bar disintegrated into rust scales and
dust when lightly touched with a test
hammer.
After recent sandblasting and/or rust
chipping
of the
internals (frames and
stiffeners)
of the hatch cover
panels, it was
noted that the support system had
completely rusted through in numerous
locations. In many locations, what remained
of the original stiffeners and frames was
now made
of paper-thin
steel.
Most of the inside steel framing and the
support system
of the
large circular grain
doors, located inside the hatch covers, had
completely rusted away. Parts of rubber
gaskets were missing
in
almost all of the
hatch cover panels. Many of the rubber
gasket channels and compression knife­
edges
on the
centerline connection between
the port and starboard side stowed hatch
panels were severely out of line or
deformed, resulting in serious leakage.
Many rubber gaskets had a very deep
imprint which, combined with a partly
disintegrating compression bar, resulted in
heavy leakage.
Standing in the forward portside corner of
hold #1, looking up it was possible to see
sunrays shining through the side (completely
deteriorated gaskets) of the ventilator cowl
located on the forecastle deck.
Ultrasonic water-tightness test were
conducted
on the hatchcovers of
holds 3
and 5 as these were the only holds that were
closed and battened down.
138
Figure CS2.3 -Hatch Supports Wasted
Away
Figure CS2.4-Disintegrated Rubber on a
Hatch Cover Cleat

129. id
1a
·~""'""""'
At the start of the discharging operations in
New Orleans there had been problems with
the hydraulic oil lines for the various hatch
covers. Several lines had burst during the
vessel's stay in New Orleans. During the
surveyor's visit onboard for the initial ultra­
sonic tests, he was told that the hatches
could not be closed because a shore-based
repair company
was fixing the
hydraulic
system.
An attempt was made to close hold #4 for
ultrasonic tests, but gallons of hydraulic oil
gushed out of the system and the attempt to
close the hold was abandoned.
Hold #3 was the only cargo hold dedicated
to the Tampa destined cargo. This hold had
not been opened since completion of
loading in Dalian. The joints/seams of the
hatch cover were still marine-taped so ultra­
sonic testing could not detect any holes
covered by the tape. Notwithstanding the
taping, several areas of heavy leakage were
still detected.
Hold #5 had contained coils discharged in
New Orleans and also still had some coils
destined for Tampa. Testing of the hatch
covers revealed many areas of very serious
leakage.
During testing, it was ascertained that some
of the new watertight doors installed in the
ventilator/access ladders to the holds had
several areas of severe leakage.
On the surveyor's departure from the vessel,
after the first attempt at ultra-sonic testing, it
was noted that the crew was starting to
replace parts of the broken or missing
rubber gaskets
in the hatch covers. The following day it was noted that several of the
missing/damaged parts of gaskets had been
replaced overnight.
Case Studies
Figure CS2.5 -Partial Replacement of
30 cm of Rubber Gasket
Note: McGregor Hatch covers, a leading
authority on hatch covering systems,
states that when gaskets are damaged,
the complete length
of the gasket has to
be replaced. Part-repairs
of gaskets will
result in uneven pressure, resulting in
leaks.
(",... ... ,..1. ·-· -....,."
Four days after the initial ultrasonic tests the
surveyor carried out
an
ultrasonic test of the
hatch covers
on
holds 1, 2, 4, 6, 7 and 8 and
noted that all drainpipes in the coamings of
all 8 holds were clogged with rust and scale.
They were inspected in detail, and it was
concluded that the only way to unclog the
pipes would be by removing the small
gratings at the bottom of each non-return
valve.
During the survey of the hatch covers, it was
noted that
on many of the hatch covers
there were
complete hatch panels, which
were permanently deformed, over the
complete length. It was concluded that, as a
result of these deformations, watertightness
would be virtually impossible to achieve,
even after repair
of
all of the previously
noted deficiencies.
139

130. Hatch Covers -Operation, Testing and Maintenance
Judging from the location/origin of these
panel deformations, it was concluded that
they were the direct result of the overall
weakness of the supporting
system/internals
of the various hatch panels. The deformations originate from
around the area where they are integrated
into the heavy hydraulic hinges for opening
and closing.
The initial and final steps in the ultrasonic
testing process are to place and remove the
transmitter from the centre
of the tanktop plating in each hold to be inspected. As the
holds are battened down for seagoing
conditions, and as there are no cargo lights
(apart from the surveyor's flashlight) inside
the closed holds, any spots of daylight
shining through the hatch covers are easily
visible to the naked eye. The surveyor hired
to carry out the ultrasonic inspection said
that,
in
several holds, he could see daylight
shining through the hatch covers in many
different locations. This was after the crew
had been working
on the hatch covers and replacing rubber gaskets for almost 2 weeks.
It was the considered opinion of the
attending surveyor that the structural
strength of the hatch covering system had
been reduced to the stage where green
seas
on deck and hatch covers
could cause
a collapse of some of the hatch panels,
potentially washing away the grain doors.
It was concluded that, as well as seawater
having entered all 8 holds, rainwater could
as easily have found its way in through the
same route.
The crew were attempting to make repairs
alongside by replacing the rubber gaskets
in
the hatch covers. However, these repairs
served
little if any purpose if the
compression knife-edge bars
on the hatch
coamings are
already partly disintegrated
and uneven
in height.
140
Claim and Subsequent
"'•· .q. .. n· ......... a... ....... ,...
The total claim from damage to the steel
cargo was US $90,000.
Fifteen coils from the total of 3,400 coils
discharged from the ship in New Orleans
and in Tampa were examined in Houston
after they had been trucked there.
The 15 were made up
of 12 cold
rolled coils
and 3 galvanized coils. It was noted that the
cold rolled coils have some minor damages,
but that the galvanized coils were heavily
damaged.
During the survey, the 15 coils were
completely unwrapped and inspected in
detail. Six coils, 3 galvanized and 3 cold
rolled were selected for complete unrolling.
The following are the general findings and
preliminary conclusions once the coils were
unpacked and unrolled.
Items (1) -(8) in sketch CS2.6 shows the
'standard' packing
of cold
rolled and
galvanized steel coils and in this case items
(9) - ( 12) shows the level of additional
packing materials that were applied to these
coils.
The cold rolled coils are well oiled whereas
the galvanized steel coils are not.There is
one crucial and distinct difference between
the cold rolled and galvanized coils'
wrapping. The cold rolled coils were initially
wrapped in heavy one-ply polyethylene­
coated Kraft paper before being plastic
wrapped, but the galvanized coils did not
have the benefit
of the heavy Kraft paper
wrapper and were
only plastic wrapped.
Silver nitrate tests carried-out in random
places
on the metal wrappers, binding
straps, carton wrappers as
well as on the
steel plating itself, showed a strong reaction
on the majority of the coils surveyed.

131. 1ils
he
~s,
g.
d
ire
llS
3Se
3S
;
3n
illy
3
:ion
Case Studies
Standard Coiled Rolls/Galvanized & Wrapping
1. Coil of Steel
2. Paper
3. Outer Circumference Sheet
4. Discs
5. Core Packing
6. Rings
7. Circumference Strapping
8. Transverse Strapping
Note/. For this cargo, item 2. was substituted
with
heavy kraft paper
lined with plastic.
~/

6
•@Y..,
@ @
Additional Wrapping on this cargo
9. Core and Outer Sheet of Carbon Between Metal Wrapper
and Plastic
10. carton Discs Between Metal and Plastic
11. Carton Core and Outer Cage Protectors
12. Heavy Plastic Sheeting Completely Wrapping Coil
Figure CS2.6 -Exceptionally Efficient Packing of the Coils.
The metal wrappers of the coils showed
signs
of heavy previous
w~tting and
associated rust formation. Removal of the
metal wrappers revealed that water had
penetrated inside the metal wrappers of all
coils. The carton liners and side discs were
wet and rust stained for almost all of the
coils. Water was seen inside all coils, on the
outside
of the heavy
plastic wrapper.
Nine
of the
cold rolled coils were found to be
free
of any type of oxidation or wetting to the
sheeting.
In three cold rolled coils, water had
penetrated inside the plastic wrapper
through small tears/abrasions. In these
cases, rust was noted to the outer windings
and/or the core windings. Unrolling of the
coils revealed that water had affected the
steel sheeting, usually for the first 75 to 100
feet and/or the last 50 feet. The 3 galvanized
coils showed signs of water infiltration inside
the wrappers. Water had also penetrated
Figure CS2. 7 -Cold Rolled Coils Showing
Infiltration Between the 2 o'clock and
6 o'clock Position
141

132. Hatch Covers -Operation, Testing and Maintenance
Figure CS2.8 -Oxidation on the cold rolled
rolled steel
through the plastic wrapper at the base of
the coils (original stowage position). Heavy
white and black oxidation was noted to the
edges
of the outer and/or inner windings
and to the affected part of the sheeting
during
unrolling. There were also areas
where water had penetrated
in between the
windings, but no oxidation had yet occurred.
On several of the cold rolled coils water had
penetrated through small tears in the plastic
wrapper, these water drops were absorbed
by the polyethylene-coated Kraft paper and
so never came into contact with the steel
sheeting itself. In the galvanized steel
sheeting/coils, because they didn't have an
inner Kraft paper wrapper, the water made
direct contact with the sheeting and was
'absorbed'
in between the
coil windings
through capillary action, resulting in
oxidation of the sheeting.
The ambient air
in Houston during
unpacking
of the
coils was very humid, with
rain and a temperature
of about
75° F
142
Figure CS2.9 -Reaction to Silver Nitrate
Unwrapping of the coils immediately
resulted in condensation forming on the
exposed steel surface of the steel coil. It
should be noted that surveyors are aware of
this natural phenomena and that the rust
formation and/or wetting identified inside the
coils was not related to the sudden
'sweating'
of the
coils after unwrapping.
Figure CS2.10 -Heavy Rust on the Inside
of the Metal Wrapper

133. )f
e
3
It is impossible to apply the findings on
15 coils from a total
of about
3,400 coils
discharged from the ship
in New
Orleans
and in Tampa. However, and this again is
due to the excellent packing of the coils, it
could be concluded on a preliminary basis
that the cold rolled coils seem to have
suffered only very limited wetting/rust
damages, whereas the galvanized coils
seem to have been much more problematic
as far as water infiltration and oxidation is
concerned.
Figure
CS2.11 -Galvanised Coils With
Signs of Wetting
Case Studies
Figure CS2.12 -Oxidation on the
Galvanised Coils
Figure CS2.13 -Heavy Oxidation on the
Galvanised Coils
Reproduced through the courtesy of
SKULD
143

134. Case Study 3
Casi Water ingress through hatch covers
on a refrigerated vessel
Date/Locattor St-Petersburg
l"'tr'r" ,.., 1-.&~-tinn·
The vessel experienced heavy seas and was
rolling and pitching heavily and suffered
water ingress that mainly affected the
packing
of the
pallets stowed in the lower
hold.
Figure CS3.1 -Hatch Coaming Showing
Where Water Entered the Refrigerated
Hold
On arrival in port, the water level reading in
cargo hold 2C was 1.20 m on the stbd side.
On the port side it was approx. 0.25 m.
Figure CS3.2 -Three Holds Suffered
Damage Due to Pallets Shifting
Case Studies
A number of pallets had capsized, collapsed
or were totally destroyed. 42 pallets were
initially found to be either damaged
completely or in a partly damaged state, but
they were then re-stowed and repacked
by
the ship's crew.
The ship's crew reconstructed the
pallets by
replacing the wooden bases, shifting the
frozen fish blocks onto new pallets and
wrapping these with new plastic film.
However, a number of the frozen blocks of
fish were plastic film wrapped only and were
so badly damaged that there was no
possibility of doing anything other than
declare them as waste
Figure
CS3.3 -Damaged Pallets
!"'·~,.~
iiijz e·e
Figure CS3.4 -Ice Build-up on the Tween
Deck
145

135. Hatch Covers -Operation, Testing and Maintenance
The cargo was discharged completely as per
the B/L, without a single remark or claim
concerning damage to the cargo and/or
cargo shortage.
It was recommended to the Master of the
vessel that he apply to the Public Notary
Office at the next port of call and arrange for
a Note of Sea Protest, as both the vessel
and cargo had suffered from an 'Act of
God'.
Reproduced through the courtesy of SKULD
146

136. Case Study 4
Cast Port of refuge required
Oat~ February 2008
[") ~r-vnrl"' V""rmr\+:,....,
A vessel experienced rough weather while
on passage from Estonia to Turkey, carrying
a cargo
of scrap
metal.
Figure CS4.1 -The Weather Experienced
on Passage
Figure CS4.2 -Scrap Metal Cargo
There was water ingress through the hatch
covers and into the holds. The vessel's bilge
suction system was inoperable because the
pump suctions were covered with net and
the ventilation pipes were covered with
refuse sacks.
Case
Studies
Figure CS4.3 -Vent Stack Covered by
Refuse Sacks
No 1 Hold was completely flooded and No 2
hold was partially flooded. Water also
passed through the ventilation trunks from
No 1 hold and flooded all of the forward
spaces (Bow thrust room, paint locker etc)
Figure CS4.4 -The Vessel Weighed Down
With the Flooded No 1 and 2 Holds,
Showing the Area Where the Bow Heavily
Contacted the Berth
While berthing in Ceuta (port of refuge after
flooding), the bow struck the quay heavily.
With no discharge facilities for a scrap metal
cargo in Ceuta, the following procedure had
to
be carried out:
147

137. Hatch Covers -Operation, Testing and Maintenance
Flooded water was pumped out using
submersible pumps
hatch covers were made watertight using
RAMEK tape or polyurethane foam
a single voyage was made to Algeciras
with tug assistance as the hold bilge
system remained inoperative
part
of the cargo was discharged to allow
access to the hold bilge boxes to clean
the bilge suction lines prior to proceeding
to the final port
of discharge.
Figure
CS4.5 -Polyurethane Foam Used to
Ensure the Watertight Integrity of the
Hatches
for the Next Leg of the Voyage For
Repairs
Reproduced through the courtesy of
SKULD
148

138. Case Study Number 5
Cas Oil leakage from the hatch
hydraulic system on to the cargo
"'
The vessel had loaded in Campana for
discharge in various ports around the
Mediterranean.
f;DAJ•,-Y,, ~
EJI 1--
~
.llil.ll
llOh
5_M.,._0.t
-·--
tJ1H ")()SE l'ipt MQST AQA~lfil
m..Ll!
tfE$ ux=t P1Pl;
t~f.4
~ '!;StA1
!!U..!.t !&-I .. 005! Jr.Pl.$
fil.IJ
ll!.lli
·1 u t: M
...
Figure CS5.1 -Cargo Plan
There was some water damage and the
rubber seals themselves (on the hatches)
were found to be in a fair condition, though
were coming away from the hatch in areas
where the glue had failed to adhere. The
hatch seal retaining channels suffered from
corrosion, with the drain holes partly
obstructed.
5-jl!.:l'(OA.
-·~1 ~ U:!.1..!.!
.12Z PiPf.
~?..ll!
,, ..
.
•v
Case Studies
!l.
Figure CS5.2 -Rubber Hatch Seal
149

139. Hatch Covers -Operation, Testing and Maintenance
There were hydraulic oil leakages from the
hydraulic oil circuit of the hatches closing
system. The vessel's hydraulic oil system
was
in a very poor condition
overall.
Figure CSS.3 -Hatch Closing Arrangement
A portion of the cargo that had shown a
positive reaction to silver nitrate testing was
placed in a storage area outside the port.
Letters
of protest from the receivers
covered:
The rusty state
of the cargo
oil dripping from the hatch and tween
deck covers
the 80 pipes stained by oil
the presence of other cargo (fertilizer)
among the load.
The exact source of the contamination was
not clear.
Reproduced through the courtesy of
SKULD
150
Figure CSS.4 -Oil Stained Pipe Cargo

140. Case Study 6
Casi Water damage due to leaking
hatch covers
Datj July 2006
The surveyor boarded the vessel to survey
the cargo, at the port
of Aden, to inspect a
cargo that had suffered water damage.
Figure
CS6.1 -Damage Below the Hatch
Coaming
The cargo
details were as follows:
3,800 Tonnes Sodium Sulphate
Anhydrous
580 Tonnes Caustic Soda flakes
1, 190 Tonnes Sodium Triplolysphate
690 Tonnes Zeolite
70 Tonnes Carbomethyl cellulose
984 Tonnes Sodium Silicate
600 Tonnes Soda Ash Light
The Ship's Master stated that only hatch
numbers 1 and 3 could be opened for
inspection. The following observations were
made:
Case Studies
Figure CS6.2 -Hatch Cover
Hatch no. 1:
The hatch coaming was clean and no
signs
of water were noted
visible cargo bags were found in apparent
good condition, except for the bags
stowed under the front hatch access.
These were yellowish and water stained
due to sea water ingress.
Hatch
no. 3:
There were sea water traces on the hatch
coamings
on the starboard side and on
the joints of the hatch cover
the bags under the sea water traces were
yellowish and water stained.
Reproduced through the courtesy of
SKULD
151

141. Case Study 7
Cas~ Alleged wet damage to Frozen Krill
Date/Locat101 June 2006 at
Shimonoseki, Japan
~r-1,~ -~ ....J '-"-~--~.a.;~ ....
A cargo of 39,469 cartons (806 net tons) of
frozen krill/krill meal was loaded in Moon
Bay, Shetland Islands in May 2006, loading
in Nos. 1A, 1 B, 2A, 2B and 3A
compartments from a Japanese trawler:
While underway, the vessel encountered
heavy weather
in the Bay of Biscay area,
with winds
of force 8 to 9 causing the
vessel
to roll, pitch and pound heavily, shipping
seas on deck and on the hatches.
The vessel arrived at in Shimonoseki and
discharge
of the frozen
krill began from
hatches Nos. 1
A and 3A. When
No. 1 A
hatch was opened the cartons
of the frozen
krill were found iced and/or wetted under the
starboard hatch coaming. The Master
advised the owners
of the condition of. the
cargo found and requested the nearest
P&I
correspondent to arrange a surveyor for
damage through their agents, as instructed
by the owners.
Inspection Findings
No. 1A compartment
Figure CS7.1 -Ice Damage Under the
Hatch Coaming
Case Studies
Ice had formed on the cartons under the
starboard hatch coaming and cartons were
partly wet and had adhered to one another
over about 4 to 5 rows and 20 tiers, involving
about 1,500 cartons (30 tons).
Silver nitrate tests proved that the ice was of
seawater origin.
The rubber packing, hatch covers and
coaming were found to be
in a
serviceable
condition and without apparent defects,
although the groove of the hatch cover side
packing was rather deep.
The forward access hatch cover packing
was
in poor condition.
Cause of Wet Damage
The cause of the damage to the cargo under
the starboard hatch coaming can be
attributed to the heavy weather encountered
by the
vessel, as reported by the Master:
However, wet damage under the access
hatch can be attributed to the bad condition
of the rubber packing of the hatch.
Further to the
preliminary report of 12 June,
2006, further inspection found
No. 1A Compartment
During discharge of the damaged
cartons, it was found that the extent of
the damage was more extensive than
previously anticipated. The wet and
damaged cartons extended to the
extremity
of the starboard side instead of
just 4 to 5 rows as
initially thought.
When the discharge was completed the
damage amounted to approximately
2,000 wetted/partly broken cartons
(40 mt)
No. 18 compartment
Shimonoseki cargo (frozen krill) in this
compartment was found
in good order.
However, about
100 blocks (about 1,500
kgs in total) of frozen squid under the
153

142. Hatch Covers -Operation, Testing and Maintenance
Figure CS7.2-Ice Frozen Squid Block
Under the Starboard Deck Hatch Coaming
in
No. 1 B Compartment.
starboard hatch coaming were
partly
iced.
As the consignees' intention of disposal
of the damaged cargo was unknown, it
was difficult to estimate the loss,
although it was believed to be in the
region of JPY 1,800,000 (US $17,000)
Reproduced through the courtesy of
SKULD
154

143. Case Study 8
Casi Water damage to fishmeal cargo
Dat1 March 2006
--•---1d Information:
Built: 1978
DWT: 3,017 Tonnes
Hatches: 2
Hatch cover rubber packing renewed
in
drydock in
July 2005
The vessel departed from the Faroes to
Greece with a cargo
of
fishmeal in March
2006. Bad weather of Force 7-8 was
experienced
in the Bay of Biscay
The
vessel arrived at Astakos on 30th March
and was berthed at 08:30 hrs on the same
day. Upon opening the hatch covers, it was
noted that the
top
of the cargo at the aft part
of the
hold had been wetted at different
locations over a length of approximately
20 metres.
Case Studies
Figure CS8.1-Vessel on Arrival
When the surveyors arrived onboard the
condition
of cargo in the aft
20 metres of the
hold was found as shown in the photo at
figure CS8.2.
Figure CS8.2 -Condition of Cargo on Arrival
155

144. Hatch Covers -Operation, Testing and Maintenance
It can be observed from the photo (CS8.2)
that the water seepage into the hold had
accumulated at points, forming small 'pools'
that, during the period of the vessel's violent
rolling and pitching, had led to a wetted a
thin layer on the top
of the cargo.
Figure
CS8.3 -Removal of Damaged Cargo
The port stevedores removed the damaged
cargo (by means
of grabs and
shovels to
minimise the mixing
of the damaged cargo
with sound cargo).
On completion of the
removal of the damaged cargo, discharge of
the sound cargo resumed. According to the
shore weighbridge measurements, the total
amount of co-mingled sound/damaged
cargo was 48,480 kgs. (note that the cargo
had been purchased at $1.39/kg).
The hatch covers were examined and found
to be structurally sound. The rubber packing
was pliable and not unduly compressed.
There were not any torn or defective
sections
of rubber packing.
It was apparent
that the rubber packing had been recently
renewed. As an extra precaution, sealing
foam had been applied at the periphery of
the hatch covers
on
completion of loading at
Fuglafjodur.
At the specific request of the cargo
underwriters' appointed surveyors, the
watertight integrity
of the No.2 (aft) hatch
156
cover was tested satisfactorily by means of
a hose test, which was carried out on
completion of cargo discharge.
Figure CS8.4 -Completing Discharge in
No.2 Hatch
Comments on
Cause of
n~m'::lrt
As it is well known, the hull of a vessel
experiences opposing moments when
waves/swell are encountered. This creates a
twisting
of the
vessel's hull structure, which
results in an unavoidable distortion of the
shape
of the hatches/hatch covers to an
extent depending on the severity of the waves/swell. Relatively (to the size of the
vessel) violent swell will cause distortion of
the hatch covers to a degree that will cause
an unavoidable reduction of the
compression
of the hatch cover rubber
gaskets at
places. Such unavoidable
reduction of the rubber gaskets allows water
to seep into the hold when green water
washes over the hatch covers.
This was a case where heavy weather was
the cause. However, it
is
possible that
incorrect use
of the
cleats may have
contributed the cargo claim. This would have
occurred if the crew had over-tightened the

145. cleats such that the hatch could not 'float' on
top of the compression bars, forcing the
hatch to 'follow' the twist of the hull and
cleats. MacGregor Hatches state that the
cleats are to keep the hatch in place and not
to place additional compression (the weight
of the hatch should be sufficient for
compression).
Reproduced through the courtesy
of
SKULD
Case Studies
157

146. Case Study 9
Casi Steel cargo damage -ship sweat
and sea water
Dat1 July 2006
R~l""'n rn1 inrl I nfnrrnation:
Total goods shipped -
3,845 new bundles I 7,555 MT
port
of
loading -
Zhangjiagang, China
port of discharge -
Aden, Yemen
weather conditions during loading -
Cloudy
weather conditions during voyage -
Up to force 7 combined with green water
over the covers
of the
holds.
Storage of goods on the vessel
Hold 2 2,265 bundles I 4,473 MT
Hold 4 = 1,580 bundles I 3,083 MT
Total= 3,845 bundles I 7,555 MT
Fig CS9.1
During discharge it was found that the steel
bundles had been exposed to serious
damage and were stained heavily by rust as
a result of condensed sweat in the holds of
Case Studies
the vessel during the voyage from China to
Aden. In addition, traces of infiltration of
seawater to the holds of the vessel were
observed and silver nitrate tests were
carried out to determine the causes
of the
heavy rust. This confirmed the presence
of
saltiness on the steel bars.
Total value of the goods = US$ 3, 7M
Estimated value of damage= US$ 931 K
Reproduced through the courtesy of
SKULD
159

147. Case Study 10
CaSE Water soaked cargo
Dati December 2006
n--·I
Built 1978
DWT 2,360
Jnd Information:
Hatches: 1 of the
folding type
~..,,., ... "
The vessel loaded 2199 MT of chalk at
Stevns Pier in Denmark for Oulu, Finland
Figure CS10.1 -Vessel Alongside
The cargo hold was not equipped with tween
decks or portable bulkheads and the holds
were of the box-type.
The vessel sailed from the east side of
Denmark in moderate seas and swell.
The wave height was approx 2.5 metres and
breaking over the hatch covers. At this time
the ship was rolling through 30° either side.
In Oulo, when the hatchcovers were opened,
it was found that the cargo had been soaked
by water over an area
of about 1.5 metres
wide, across the
length of the cargo hold.
Case Studies
Considering the vessel's age it was in good
condition and while the gaskets on the hatch
coamings were slightly pressed together
they were still quite elastic. The hatch
coaming gasket bars were
in moderate
condition but no signs
of
substantial
deformation were seen. The gasket bar was
found to be only extending to about 20 mm.
No drainwells were found on the longitudinal
sides.
Figure CS10.2 -The Corner Longitudinal
Gasket has a Hole of Approximately
20mm
161

148. Hatch Covers -Operation, Testing and Maintenance
Figure CS10.3 -Cargo Discharged From the After Part of the Hold
Figure CS10.4 -Gaskets are Slightly Pressed
162

149. Figure CS10.5-Chalk Cargo Contaminated by Water
Figure CS10.6-Signs of Water Entry
Reproduced through the courtesy of
SKULO
Case Studies
163

151. Appendix 1
RESOLUTION MSC.169(79)
(adopted on 9 December 2004)
STANDARDS FOR OWNERS'
INSPECTION AND MAINTENANCE OF
BULK CARRIER HATCH COVERS
THE MARITIME SAFETY COMMITTEE,
RECALLING Article 28(b) of the Convention
on the International Maritime Organization
concerning the functions of the Committee,
RECALLING ALSO SOLAS Chapter XII on
Additional safety measures for bulk carriers,
which the 1997 SOLAS Conference adopted
with the aim
of enhancing the safety of
ships carrying
solid bulk cargoes,
RECALLING FURTHER that, having
recognized the need to further improve the
safety
of
bulk carriers in all aspects of their
design, construction, equipment and
operation, it examined the results of various
formal Safety Assessment (FSA) studies on
bulk carrier safety,
RECOGNIZING that, on the basis of the
outcome of the aforementioned FSA
studies, replacing hatch covers in existing
bulk carriers would not be cost-effective and
that, instead, more attention should be paid
to hatch cover securing mechanisms and the
issue
of
horizontal loads, especially with
regard to maintenance and frequency
of
inspection,
RECALLING that, at its seventy-seventh
session,
in approving
MSC/Circ.1071 -
Guidelines for bulk carrier hatch cover
surveys and owners' inspections and
maintenance, it invited Member
Governments to ensure that companies, as
defined
in the
ISM Code, that operate bulk
carriers flying their flag are made aware of
the need to implement regular maintenance
and inspection procedures for hatch cover
closing mechanisms in existing bulk carriers
Appendices
in order to ensure proper operation and
efficiency at all times,
NOTING resolution MSC.170(79) by which it
adopted,
inter a/ia, amendments to regulation Xll/7 (Survey and maintenance of
bulk carriers) of the Convention, where
reference
is made to mandatory Standards
for owners' inspection and maintenance
of
bulk carrier hatch covers,
HAVING CONSIDERED the
recommendation made by the
Sub-Committee on Ship Design and
Equipment at its forty-seventh session,
1. ADOPTS, for the purposes of the
application of regulation Xll/7 of the
Convention, the Standards for owners'
inspection and maintenance
of
bulk
carrier hatch covers, set out in the Annex
to the present resolution;
2. INVITES Contracting Governments to the
Convention to note that the annexed
Standards will take effect on 1 July 2006
upon the entry into force of the revised
Chapter XII of the Convention;
3. REQUESTS the Secretary-General to
transmit certified copies
of this
resolution
and the text of the annexed Standards to
all Contracting Governments to the
Convention;
4. FURTHER REQUESTS the Secretary­
General to transmit certified copies of this
resolution and the text of the annexed
Standards to all Members of the
Organization which are not Contracting
Governments to the Convention.
167

152. Hatch Covers -Operation, Testing and Maintenance
Annex
STANDARDS FOR OWNERS'
INSPECTION AND MAINTENANCE OF
BULK CARRIER HATCH COVERS
1 Application
These Standards define requirements for the
owners' inspection and maintenance of
cargo hatch covers
on board
bulk carriers.
2 Maintenance
of hatch covers and hatch
opening,
closing, securing and sealing
systems
2.1 Lack of weathertightness may be
attributed to:
1. Normal wear and tear of the hatch
cover system: deformation
of the
hatch coaming or cover due to
impact; wear of the friction pads
where fitted; wear and tear of the
cleating arrangement; or
2. Lack of maintenance: corrosion of
plating and stiffeners due to
breakdown of coatings; lack of
lubrication of moving parts; cleats,
joint gaskets and rubber pads in
need of replacement, or replaced
with incorrect specification parts.
2.2 Insecure hatch covers may be
particularly attributed to damage or
wear of securing devices, or incorrect
adjustment, and incorrect pre-tension
and load sharing, of cleating systems.
2.3 Shipowners and operators shall
therefore institute a programme of
maintenance. This maintenance shall
be directed to:
168
1. Protecting exposed surfaces of
plating and stiffeners of hatch covers
and coamings
in order to preserve overall structural strength;
2. Preserving the surface of trackways
of rolling covers, and of compression
bats and other steel work bearing on
seals or friction pads, noting that
surface smoothness and correct
profile are important for reducing
wear rate~ on these components;
3. Maintaining hydraulic or
mechanically powered opening,
closing, securing or cleating systems
in accordance with manufacturer's
recommendations;
4. Maintaining manual cleats in
adjustment, with replacement when
significant wastage, wear or loss of
adjustment capability is identified;
5. Replacing seals and other wear
components
in accordance with
manufacturers' recommendations,
noting the need to carry
on board or
obtain such spares of correct
specification, and that
seals are
designed for a particular degree of
compression, hardness, chemical
and wear resistance; and
6. Keeping all hatch cover drains and
their non-return valves, where fitted,
in working order, noting that any
drains fitted to the inboard side of
seal lines will have non-return valves
for prevention of water ingress to
holds in the event of boarding seas.
2.4 The equalization of securing loads shall
be maintained following the renewal of
components such
as
seals, rubber
washers, peripheral and cross joint
cleats.
2.5 Shipowners and operators shall keep
a Maintenance Plan and a record of
maintenance and component
replacement carried out, in order to
facilitate maintenance planning and
statutory surveys
by the Administration.
Hatch cover maintenance
plans shall
form part of a ship's safety
management system as referred to
in
the
ISM Code.
2.6 Where the range of cargoes carried
requires different gasket materials, a
selection of gasket materials of the

153. correct specifications shall be earned
on board,
in addition to other spares
2.7 At each operation of a hatch cover,
tne
cover and,
in
particular, bearng
surfaces and drainage channe'.s shall
be free of debris and as clean as
practicable.
2.8 Attention is drawn to the da,..gsrs o:
proceeding to sea without f'u.11/ secured
hatch covers. Securing of all covsrs
shall always be completed be"ore L1e
commencement ofa sea oassage.
During voyages, especi
a.
1 o'.":. 'oaded
passages, cover securing ce·.~css a'ld
tightness of cleating and secu...;,.,g
arrangements shall be Chee· ed
especially in anticipatior o: a'i
following periods of, severe :. eatne.
Hatch covers may only oe openeC' o
passage, when nece
ssar
1
cunn,g
favourable sea and weatrer cor.d"Jons:
imminent weather forecas:s s-,a
be considered.
2.9 Operators shall consult tre Cargo
Securing Manual when planr '19 ~ne
loading of c~mtainers or other cargo on
hatch covers and confirm that they are
designed and approved for such loads.
Lashings shall not be secured to the
covers or coamings unless these are
suitable to withstand the lashing forces.
3 Inspection of hatch covers and hatch
opening, closing, securing and sealing
systems
3.1 Statutory surveys of hatch covers and
their coamings are carried out by the
Administration as part
of the
annual
survey required by article 14 of the
International Convention on Load Lines,
1966, as modified by the 1988 Protocol
relating thereto and in accordance with
the requirements for Enhanced Surveys
contained in resolution A.744(18), as
amended. However, the continued safe
operation
is dependent on the
shipowner
or operator instituting a
Appendices
regular programme of inspections to
confirm the state
of the hatch covers in
between surveys.
3.2 Routines
shall be established to
perform cheeks during the voyage, and
inspections
when the hatch covers are
opened.
3.3 Voyage checks
shall consist of an
external examination of the closed
hatch covers and securing
arrangements
in anticipation of, and
after, heavy weather but
in any event at
least once a week, weather permitting.
Particular attention shall be paid to the
condition
of hatch covers in the forward
25%
of the ship's
length, where sea
loads are normally greatest.
3
.4 The
following items, where provided,
shall be inspected for each hatch cover
set when the hatch covers are opened
or are otherwise accessible on each
voyage cycle, but need not be inspected
more frequently than once per month:
1. Hatch cover panels, including side
plates, and stiffener attachments of
opened covers for visible corrosion.
cracks or deformatio
n;
2.
Sealing arrangements of perimeter
and cross joints (gaske:s. ~ex 01e
seals on combination car"ers
gasket lips, COmpreSSIO" oars
drainage channels a'lc 'lon-return
valves) for condition and
permanent deforlT'ation;
3. Clamping devices re~ ,.., "9 bars
and cleating for ,.,,as~ge
adjustment, ard cor:c.:.or: of
rubber components;
4. Closed cover locating de. ices for
distortion ard al..achmem·
5. Chain or v. re rcae pu'. e;s;
6. Guides:
7, Guide rats ar.c trac~ •;,"ieels;
8. Stoppers
169

154. Hatch Covers -Operation, Testing and Maintenance
9. Wires, chains, tensioners and
gypsies;
10. Hydraulic system, electrical safety
devices and interlocks; and
11. End and inter-panel hinges, pins
and stools where fitted.
As part of this inspection, the coamings
with their plating, stiffeners and
brackets shall be checked at each
hatchway for visible corrosion, cracks
and deformation, especially of the
coaming tops and corners, adjacent
deck plating and brackets.
Source www.imo.org
170

155. Feature
SOT Coltraco
Equipment:
SDT101,
SDT13(A)
Porta
scanner
SDT150, SDT2000
Manufacture:
Belgium
United
Kingdom
Equipment: 1 x 8 transducer unit fitted 1 x
small single
transmitter
Generator with carrying strap. unit, and/or 1 x 17
multiple
OR SDT13(A)
13 transducer transducers. High/Low
unit fitted with carrying strap. power
available.
Hook
provided on top. Heavy and
cumbersome,
easily
dropped!
Equipment: Receiver unit Receiver unit.
Originally
with
Receiver sensor in front, now
extension with sensor in
end.
Carriage/packing: Foam
lined
Samsonite Reinforced box for
suitcase. transmitter. Case for
receiver.
Headphones
Noise
isolating.
Large Noise
isolating.
Unable
to use with hard hat
Unable
to use with hard hat
Display
: Unit available
with LED or
Analogue
LCD readout, no
with
digital scale.
fixed reading.
Power:
Rechargeable power unit. 12 x size 'C'
alkaline
Transmitter
230
V,
50
Hz. batteries
or
multivoltage
rechargeable power unit.
Power:
Rechargeable power unit. 2 x 1.5
volt
batteries
Receiver
230
V,
50
Hz.
Battery
Life:
Tx
Max 4 hours,
usually
3 hrs
Daily
use -
6 months
Rx: 3 hours
Daily
use -
6 months
_... -...J
UE
Systems
SOT
Ultraprobe 2000 Sherlog
TA
USA
Finland/Belgium
1 x
small single
transmitter 1 x 8 transducer unit fitted
unit, and/or 1 x 4 transducer with carrying strap.
Dual
multi-directional
tone frequency.
generator. No hook
or
strap 1.5 kg
provided.
Receiver unit in form
of
203
x 38 x 88 mm
handheld
gun.
900
g.
Rechargeable batteries.
10-00
dBmV
Rubberised exterior for grip.
Foam
lined aluminium
Foam
lined Samsonite
suitcase. suitcase.
Noise
isolating.
Large. Noise
isolating.
Large.
Unable
to use with hard hat
Unable
to use with hard hat
Digital
and LED
Digital scale
Rechargeable power unit
12V
de.
Rechargeable
110 V
or
230 V
power unit
110-230
V
6 settings for various
applications.
Rechargeable power unit 6
cell
rechargeable
110
Vor
230 V
5-6 hours Max 4 hours
5-6 hours Max 4 hours
Class
Instrumentation
CargoSafe
Mark
Ill
United
Kingdom
1 x 13 transducer unit. 350
g
Fits in
pocket.
Whawha sound can be
varied with
multiple
frequencies. 160
x 92 x 32 mm
300
g
0-160 dBmV
reading.
Foam
lined small
sized
plastic
case.
Or
optional
rucksack.
Noise
isolating.
Light.
Useable
with a hard hat.
Can
also
use any
available
headphones or earpiece Digital scale
Switchable
from dB to %
OHV 6 standard
'AA
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156. Index
Index
ABS .............................................................................................................................. 115, 116
Access ................
3, 14, 19,
20, 24, 61, 64, 65, 67, 88, 101, 106-110, 127, 139, 148, 151, 153
Air test .............................................................................................................................. 93, 94
Alarms .............................................................................................................................. 59, 60
Aluminium covers ...................................................................................................................... 9
Aluminium Foam .................................................................................................................. 171
Ambient air ............................................................................................................................ 142
Approval certificate ...................................................................................................... 105, 116
Ballast .............................................................................................. 20, 27, 28, 54, 59, 60, 110
Bearing pads ...................... 14, 32-35, 38, 44-45, 49-50, 79, 82-83, 90, 95, 107, 121, 127, 134
Bearing panels ........................................................................................................................ 40
Bilge .................................................................................................................. 68, 88, 147, 148
Bosun's store .................................................................................................................... 57-59
Box construction ............................................................................................................ 68, 134
Box holds ................................................................................................................................ 61
Box type ............................................................................................ 21, 27, 28, 39, 50, 65, 129
Bulk cargoes .............................................................................................. 19, 20, 55, 101, 167
Bulk carriers .................. 3, 10, 19, 20, 30-31, 47, 49-50, 54-56, 59-60, 89, 105, 110, 167, 168
Bulkhead .............................................................................................................. 56, 59, 61, 93
Calibration .................................................................................................................... 105, 115
Capesize .......................................................................................................................... 20, 49
Cargo access ................................................................................................... ................. 19, 20
Cargo handling ................................................................................................................ 20, 21
Cargo nets .............................................................................................................................. 29
Cargo operations ..................................................................................... 42, 61, 64, 93-95, 101
CargoSafe ............................................................................................ 104-107, 110, 115, 171
Carton liners ...... : ................................................................................................................. 141
Cat system .................................................................................... 27, 45, 48-49, 58, 61, 67, 69
Cement ...................................................................................................................... 19, 27, 76
Certification ...................................................................................... 55, 87, 105, 109, 115-118
Chafing .......................................................................................................................... 44, 128
Chalk test ................................................................................................................................ 93
Chartering/charterers .......................................................................... 55, 76, 88, 89, 109, 115
Check-lists ................................................................................................................ 89, 90, 117
Chemicals .................................................................................................... 19, 23-24, 116, 168
Clamping devices ................................................................................................................ 169
Class ............................................................ 3, 21, 59, 60, 87, 88, 104-111, 113, 115-118, 171
Clay test ............................................................................................................................ 93, 95
Cleats .............. 14-16, 27-35, 38-40, 42-43, 49-54, 61, 64-68, 70, 81, 90, 93, 101, 128, 134,
138,
156, 157, 168-169 Angled .................................................................................................................. 29
Autocleats ............................................................................................................ 54
Bearing cleats ...................................................................................................... 33
Bolt cleats ...................................................................................................... 51, 61
Claw Type Cleat. ............................................................................................. 70, 71
Hold-down cleat .............................................................................................. 66, 67
Joint wedge cleats ................................................................................................ 31
173

157. Hatch Covers -Operation, Testing and Maintenance
Quick acting cleats .................................................. 31-33, 40, 49, 51, 61, 66, 134
Shoe Cleats ........................................................................... ............................... 40
Side cleats ............................................................ 35, 38, 43, 50, 51, 53, 54, 64, 68
Closing devices ...................................................................................................................... 10
Coal .............................................................................................................. 19, 20, 55, 89, 100
Coamings ............ 13-15, 19-20, 27-32, 34-36, 48-50, 52, 54, 60-61, 64, 67, 70, 76, 79, 81-84,
88-90, 93, 99, 110, 124, 133-135, 137, 139, 140, 151, 161, 168-170
Butting-up coamings ............................................................................................ 28
Cross Coaming ....................................................................................................
31
Coaming bar ........................................................................................... 27, 48,
110
Moon coaming .................................................................................................... 153
Coatings .................................................................................................................... 38, 42, 162
Coltraco ................................................................................................ 103, 110, 111, 115,
171
Combination carriers ............................................................................................ 3,
50, 61, 169
Consequential damage ........................................................................................................ 128
Consequential reduction ......................................................................... ................................. 5
Containers ............................................................................
3,
20-23, 61, 65-68, 105, 106, 169
Corrosion ......................................
5, 38,
40, 42, 44-45, 76, 79, 80, 82, 89, 108, 110, 121-124,
128-129, 149, 168-170
Cranes ............................................................................ 9, 19-21, 28-30, 37, 38, 40, 67-68, 83
Crew access ................................................................................................. ." ........................ 88
Cropping ..............
........................................................... : .............................................. 59, 129
Cross joint..
.. 27, 31-33, 35, 37, 38,
40, 46, 49, 51, 53, 54, 61, 67, 94, 123, 127, 128, 134, 168
Damage ............................
3, 5,
30, 33, 56, 57, 68, 76, 79, 80, 83, 88, 121, 123, 127, 128,
135, 140, 145, 146, 149, 151, 153, 155, 156, 159, 168
Datalogging .................................................................................................................. 106, 108
Deck log books .................................................................................................................... 135
Defects .................................................... 79, 80, 83, 87, 88, 108, 109, 119, 121, 123, 127, 153
Deformation ..............................................................................................
3, 129, 161,
168-170
'Derbyshire' ........................................................................................................................ 55-60
Derricks .................................................................................................................... 19, 28, 29
Dirt .................................................................................................................................... 46, 83
DNV .................
..................................................................................................................... 115
Dogs ...................................................................................................................................... 58
Double skin ............................................................................................................ 3, 21, 27, 61
Drain channels .......................................... 14, 27, 28, 31-32, 50, 80-84, 94, 121, 123, 134-135
Drainage .......................................................... 14, 15, 27, 31, 34, 39, 50, 61, 67, 68, 100, 169
Drainpipes .................................................................................................................... 135, 139
Electric windlasses ................................................................................................................ 31
Electrical safety devices ........................................................................................................ 170
Erosion .................................................................................................................................... 44
Face seals .............................................................................................. 33, 49, 53, 69 123, 128
Feeder vessels ............................................................................................................ 20-21, 66
Fertilizer ........................................................................................................................ 137, 150
Fire ........................................................................................................................ 14, 60, 76, 94
Flexseal system ...................................................................................................... 34-35, 44-45
Foam ................................................................................................ 76, 103-105, 148, 156,
171
174

158. Index
Folding covers .............................................................................................................. 0, 38, 39
Foldtite ........................................................................................................................ 27, 39, 41
Forest products ................................................................................................................ 19, 23
Fork-lift trucks ............................................................................................................ 27, 64, 68
Free surface ...................................................................................................................... 19, 20
Freeboard ........................................................................................................ 4, 21, 23, 24, 57
Frozen Cargo .......................................................................................................................... 68
FSA ...................................................................................................................................... 167
Galvanized steel .................................................................................................. 137, 140, 142
Gantry ..........................................................................................................................
9, 19, 21
Gaskets .................................................................................. 138-140, 156, 161-162, 168-169 General cargo .................................................................................................. 23-24 30, 39, 47
Grain ................................................................................................... 19, 27, 55, 137, 138, 140
Grease ............................................................................................................ 42, 54, 79, 82-84
Handymax .............................................................................................................................. 19
Hatch Cover Seal .......................................................................................... 94, 110, 127, 149
Hatch design ....................................................................................................................
9,
101
Hatch panels ............................................................................................................ 27, 138-140
Hatchway ............................................................................................. .47, 50, 61, 64, 110, 170
Heavy seas .......................................................................................... 3, 4, 29, 58, 59, 76, 145
Helicopter .............................................................................................................................. 57
Hooks ................................................................................................................................ 29, 42
Hose testing ................................................................................ 87, 93,
94,
109, 117, 135, 156
Hot work ................................................................................................................................ 129
Hydraulic jacks .................................................................................... 10, 52-54, 61, 62, 64, 90
Hydraulic lifting ................................ , ............................................................................... 36, 50
Hydraulic pipes ................................................................................. .43, 50, 54, 65, 68, 83, 90
Hydraulic ram .... : ......................................................................... 10, 39-412 44, 54, 68, 90 105
Hydraulic system ............................................................................................ 83, 139, 149, 170
Hydrostatic pressure .............................................................................................................. 94
IACS .................................................................................................................. 59, 60, 116-118
Ice .......................................................................................................................... 84, 145, 153
Inert gas ................................................................................................................................ 129
Inner barrier ............................................................................................................................ 32
Inner doors .............................................................................................................................. 17
Insulation ........................................................................................................................ 23, 68
Insurance .................................................................................................................... 79, 87-88
Integrity ................................................................................................ 3-5, 24, 60, 93, 148, 156
International Transport Federation (ITF) ................................................................................ 57
Investigations ........................................................................................................ 55-59, 87, 89
Iron ore ...................................................................................................................... 19, 20, 55
ISM Code ...................................................................................................................... 167, 168
Ladders .................................................................................................................. 14, 107, 139
Lashing .................................................................................................................... 23, 66, 169
Leaks .........................
.4, 14, 43,
50, 54, 64-65, 68, 79, 68, 80, 82, 83, 88-90, 93, 94, 99, 101,
105, 107-110, 123, 127, 133, 137-139, 149, 151
Letters of protest .................................................................................................................. 150
175

159. Hatch Covers -Operation, Testing and Maintenance
Liquid cargo ............................................................................................................................ 20
Loading .............................. 19, 27, 30, 55, 59, 60, 88, 108, 135, 137, 139, 153, 156, 159, 169
Loadline ................................................................................................ 3, 87, 93, 109, 117, 169
Locators ............................................................................................................................ 27, 68
Locker ...................................................................................................................... 57, 58, 147
Locking .......................................................................... 23, 30, 35, 36, 42, 53, 60, 64, 83, 105
Logs ...................................................................................................................... 23, 24, 30, 61
Longitudinal movement .......................................................................................................... 60
Longitudinal strength ............................................................................ 3, 31, 48, 56, 60, 61, 65
LR Test .................................................................................................................................. 116
Lubripad .......................................................................................................................... 44, 45
Lugs ........................................................................................ 31, 40, 42, 51, 61, 66, 68, 79,
81
MacGregor .............. 15, 21, 34, 35, 43-46, 52, 53, 62, 63, 66, 67, 87,
105, 106, 115, 118, 157
Maintenance planning .......................................................................................................... 168
MARIN .............................................................................................................................. 58, 59
Marine Surveyor .................................................................................................. 85, 87,
89,
108
Master .................................................................. 3, 55, 90, 108, 109, 135, 137, 146, 151, 153
MCA ........................................................................................................................................ 87
Movement ..............................................................................................
3, 4, 32,
60, 64, 82, 83
Multi-purpose vessels ................................................................................................ 23, 39, 61
Munck Loader ................................................................. ,. ............................ : ......................... 19
Nitrate tests .................................................................................................. 140, 150, 153, 159
Non return bars ...................................................................................................................... 38
Non-return valves ............................................................................................ 27, 76, 134, 168
Non-watertight ................................................................................................ 76, 106, 107, 110
Nozzle hold ............................................................................................................................ 94
OB0 ...................................................................................................................... 20, 27, 50, 55
OHV .............................................................................................................. 107, 109, 110, 171
Outturn .................................................................................................................................. 88
oxidation ........................................................................................................................ 141-143
P&l .................................................................................... 23, 61, 68, 76, 87, 88, 109, 115, 153
Packing ................ 28, 48, 68, 79, 127,
128, 134, 135,
140, 141, 143, 145, 153, 155, 156,
171
Pads .................. 14, 32-35, 38,
40, 44, 45, 49, 50, 60, 79, 82, 83, 90, 107, 121, 127, 134, 168
Pallets ................................................................................................................................... 145
Pana max .......................................................................................................................... 20-22
Panel rollers ...................................................................................................................... 38, 52
Panel Wheel. ......................................................................................................................... 128
Penetration
of water .............................................................................................................. 76
Piggy-back ........................................................................................................................ 61-63
Piggy-Back Hatch
Covers ...................................................................................................... 63
Pipes ............................ 14, 42, 43, 50, 54, 59, 64, 65, 68, 82, 83, 90, 134, 135, 139, 147, 150
Pit-props ................................................................................................................................ 23
Plates .................................................................. 4, 14, 19, 27, 29, 37, 64, 66-67, 90, 135, 169
Plating .................................................................................................... 56, 134, 140, 168, 170
Pollution ............................................................................................................................ 84, 88
Pontoons .......................................................................................... 10, 28-30, 66, 68, 106, 107
Pulleys ...................................................................................................................... 52-54, 169
176

160. Index
QC Program standards ........................................................................................................ 116
Quadruple panels .................................................................................................................. 66
Raising devices ...................................................................................................................... 83
Rams ........................................................................................................ 10, 27, 41-43, 54, 90
Reefer vessels ........................................................................................................................ 68
Rigidity .............................................................................................. 14, 31,
39, 48,
50, 61, 65
Rolled steel .......................................................................................................................... 142
Rollers ...................................................................... 14, 31, 35-38, 42, 52, 53, 61, 64, 90, 122
Rolling covers .......................................................................................................... 50, 61, 168
Rolltite .............................................................................................................................. 27, 47
Rubber protection ................................................................................................................ 104
Rubber seals ............ 15, 24, 27, 28, 31, 32, 34, 35, 38, 40, 44, 45, 46, 48-50, 53, 58, 69, 79,
80, 95, 121, 24, 127, 128, 138-140, 149, 156
Rust ........................................................................................ 79, 134, 137-139, 141-143, 159
Safe operation ................................................................................................................ 83, 169
Safety ...................................................................... 27, 57, 59, 83, 90, 107, 110, 167, 168, 170
Sagging .................................................................................................................................... 3
Samsonite .................................................................................................................... 103, 171
Seal channel ...................................................................................... 31, 80, 95, 124, 127, 129
Sealing foam ........................................................................................................................ 156
Sealing mechanism .............................................................................................................. 23
Sealing tapes ........................................................................................................................ 135
Sealing valves ...................................................................................................................... 169
Seals ................ 24, 33-35, 38-40, 43-45, 49, 50, 53, 54, 64, 67-69, 76, 79, 80, 82, 83, 90, 93
94, 109, 110, 121, 123, 127, 128, 134, 137, 149, 168, 169
Second barrier ........................................................................................................................ 80
Securing devices .............................................. 27, 29, 32, 40, 49, 51, 61, 65, 66, 83, 168, 169
Shackle ............. ,: ................................................................................................................... 40
Sheeting ..................................................................................................................•... 141, 142
Sherlog ................................................................................................ 103-107, 115, 116,
171
Shimming .......................................................................................................................... 45, 83
Side chains ...................................................................................................................... 36, 37
Single skin covers ............................................................................................................ 21, 65
Skuld ...................................................... 88, 135, 143, 146, 148, 150, 151, 154, 157, 159, 163
Stability ................................................................................................ 3, 4, 19, 20, 43, 68, 107
Stays .................................................................................................................... 13, 14, 31, 90
Stevedores .................................................................................................... 14, 108, 109, 156
Stowage ................
3, 14, 21, 23, 27, 29, 36, 37,
40, 42-43, 47, 49, 53, 61, 64, 67, 68, 88, 142
Sweat .................................................................................................................................... 159
Swing-seal systems .............................................................................................................. 46
Tarpaulin ................................................................................................................ 9, 10, 27-29
Tensioners ...................................................................................................................... 90, 170
Timber ................................................................................................ 10, 19, 23, 24, 28, 30, 61
Triple-panel configurations .................................................................................................... 21
Tweendeck .......................................................................................... 38, 64, 65, 93, 100, 109
Ultrasonic ...................................................................................................... 104, 117, 138-140
Ultrasound ................ 76, 87, 93, 97, 99-101, 103, 105, 107-109, 111, 113, 115, 117, 121, 123
171
177

161. Hatch Covers -Operation, Testing and Maintenance
Underwriters ............................................................................................................ 68, 88, 156
Valve ...................................................................................................................... 94, 124, 139
Valves .............................................................. 27, 28, 76, 81, 90, 94, 124, 134, 139, 168, 169
Ventilation ............................................................................................................ 108, 137, 14 7
Ventilator cowl ...................................................................................................................... 138
Ventilators ...................................................................... 20, 27, 28, 54, 59, 60, 68, 88, 94, 110
Vibration .......................................................................................................................... 83, 104
Visible corrosion .......................................................................................................... 169, 170
Visual examination .................................................................................................................. 79
VLOC ...................................................................................................................................... 20
Void spaces ............................................................................................................................ 58
Water sensitive cargoes .......................................................................................................... 54
Water traces .................................................................................................................. 135,
151
Watertightness .................... 3-5, 14, 23-24, 32, 38,
40, 43-44, 49-50, 54, 64, 68, 73, 75-76, 88
93, 101, 134, 139, 148, 156
Weathertightness ......................................
3, 14, 23-24, 28, 68, 73, 75-76, 88-89, 93,
110, 168
Wedges ..............................................................................................................
9,
28-30, 38, 40
Wet damage .......................................................................................................................... 153
Windlass .............................................................. 31, 36,
37,
40, 49, 50, 53, .58, 61, 81, 83, 90
178

162. ISBN 1-856-09344-6
111111111111111111111111
9 781856 093446