INTRODUCTION TO TERM USED IN NAVAL ARCHITECT

these slides are helpfull for understanding the terms used in naval architect.

1. Illustration of terms used in Naval Architecture
It is essential in the study of the subject to have a clear understanding of the
meaning of the various terms, abbreviations and symbols used.

2. Definition of Principal terms used in Definition of Principal terms used in
Naval ArchitectureNaval Architecture
Forward PerpendicularForward Perpendicular (FP) is a vertical line through (FP) is a vertical line through
the inter-section of the load waterline and the stem the inter-section of the load waterline and the stem
contour.contour.
AfAfter Perpendicularter Perpendicular (AP) is at where the aft side of (AP) is at where the aft side of
the sternpost meets the load waterline the sternpost meets the load waterline or or if there is if there is
no sternpost at the centre rudder stock.no sternpost at the centre rudder stock.
Length between PerpendicularsLength between Perpendiculars (LBP) is the (LBP) is the
horizontal distance between the forward and after horizontal distance between the forward and after
perpendiculars. perpendiculars.

AmidshipsAmidships (0 0) is the midway point between the (0 0) is the midway point between the
perpendiculars.perpendiculars.
MidshipMidship Section Section is the transverse section of the ship is the transverse section of the ship
at amidshipsat amidships. .

3. Illustration of terms used in Naval Architecture

4. Definition of Principle terms used in Naval Definition of Principle terms used in Naval
ArchitectureArchitecture
Breath MouldedBreath Moulded (B mld) is measured at amidship and is the maximum (B mld) is measured at amidship and is the maximum
breadth over the frames.breadth over the frames.
Depth MouldedDepth Moulded (D mld) is the vertical distance at amidships top of keel to (D mld) is the vertical distance at amidships top of keel to
the top of the deck beam at side the top of the deck beam at side or or underside of deck plating at the ship underside of deck plating at the ship
side:side:
Draught MouldedDraught Moulded (H mld) is the distance of the top of the keel below the (H mld) is the distance of the top of the keel below the
waterline.waterline.
Draught Draught (H)(H) is the distance of the lowest point of the keel below the is the distance of the lowest point of the keel below the
waterline.waterline.
Moulded Base Line.Moulded Base Line. This is a horizontal line which passes through the top This is a horizontal line which passes through the top
of the keel at amidshipsof the keel at amidships
Sheer.Sheer. The longitudinal curvature given to decks‘The longitudinal curvature given to decks‘
Camber.Camber. This is the curvature given to a deck transversely. The camber This is the curvature given to a deck transversely. The camber
amidships is frequently one-fiftieth of the breadth (B) of the ship.amidships is frequently one-fiftieth of the breadth (B) of the ship.

5. Definition of Principal terms used in Naval ArchitectureDefinition of Principal terms used in Naval Architecture
Rise of FloorRise of Floor is the rise of the bottom shell plating measured transversely amidships is the rise of the bottom shell plating measured transversely amidships
at the moulded breadth line.at the moulded breadth line.

Tumble-HomeTumble-Home. The fall in of the sides amidships.. The fall in of the sides amidships.
FlareFlare.. The outward curvature of the forward sections above the waterline. The outward curvature of the forward sections above the waterline.
RakeRake.. The departure from the vertical of any line in profile such as the stem. The departure from the vertical of any line in profile such as the stem.
TrimTrim.. The longitudinal inclination of a ship is measured by difference between the The longitudinal inclination of a ship is measured by difference between the
draughts forward and aft. When the draughts are the same forward and aft the ship draughts forward and aft. When the draughts are the same forward and aft the ship
is said to be ("on an even Keel”). "Down by the head” when the draught forward is is said to be ("on an even Keel”). "Down by the head” when the draught forward is
greater than aft. "Down by the stern” when the draught aft is greater. greater than aft. "Down by the stern” when the draught aft is greater.

HeelHeel.. The inclination of the ship in the transverse direction measured in degrees. The inclination of the ship in the transverse direction measured in degrees.
YawYaw.. The movement from the mean course of a ship in the horizontal plane, The movement from the mean course of a ship in the horizontal plane,
measured in degrees.measured in degrees.

6. Definition of Principle terms used in Naval ArchitectureDefinition of Principle terms used in Naval Architecture
Middle Line PlaneMiddle Line Plane. . Ships have only one symmetry, called the Ships have only one symmetry, called the
middle line plane and it is the principal plane of reference. The middle line plane and it is the principal plane of reference. The
shape of the ship given by this plane is known as the profile.shape of the ship given by this plane is known as the profile.
WaterplanesWaterplanes are planes at right angles to the middle line plane; are planes at right angles to the middle line plane;
they are symmetrical about the middle line plane. Waterplanes they are symmetrical about the middle line plane. Waterplanes
looked at edge on in the profile are called waterlines.looked at edge on in the profile are called waterlines.

Transverse PlanesTransverse Planes perpendicular to the middle line plane show the perpendicular to the middle line plane show the
shape of vertical sections of the ship.shape of vertical sections of the ship.
Freeboard.Freeboard. The vertical distance between the actual or permissible The vertical distance between the actual or permissible
waterline and the upper surface at side of the deck to which it is to waterline and the upper surface at side of the deck to which it is to
measured measured

7. Definition of Principal terms used in Naval ArchitectureDefinition of Principal terms used in Naval Architecture
Load Line MarkLoad Line Mark. . All merchant ships, with a few All merchant ships, with a few
exceptions, must be marked with a load line. The upper exceptions, must be marked with a load line. The upper
edge of this line indicates the maximum permissible edge of this line indicates the maximum permissible
draught. The load lines are set off amidships on both draught. The load lines are set off amidships on both
sides of the ship, at specified distances below a deck sides of the ship, at specified distances below a deck
line. The standard markings for a cargo ship are as line. The standard markings for a cargo ship are as
under:under:
S = Summer T = TropicalS = Summer T = Tropical
W = Winter F = Fresh W = Winter F = Fresh
WaterWater
WNA = Winter North Atlantic WNA = Winter North Atlantic
TF = Tropical Fresh WaterTF = Tropical Fresh Water

The upper edge of the summer line, if continued passes The upper edge of the summer line, if continued passes
through the centre of the load line disc and is the basis through the centre of the load line disc and is the basis
line.line.

8. Parallel Middle body
Illustration of terms used in Naval Architecture

9. Definition of Principal terms used in Naval ArchitectureDefinition of Principal terms used in Naval Architecture

Parallel Middle BodyParallel Middle Body. . The length over which the midship The length over which the midship
section remains constant in area and shape. section remains constant in area and shape.
Fore BodyFore Body. . The immersed body forward of the midship The immersed body forward of the midship
section.section.
AfterAfter BodyBody. . The immersed body aft of the midship section.The immersed body aft of the midship section.
Entrance.Entrance. The immersed body forward of the parallel body.The immersed body forward of the parallel body.
Run.Run. The immersed body aft of the parallel body The immersed body aft of the parallel body

10. Illustration of terms used in Naval Architecture

11. Definition of Principal terms used in Naval ArchitectureDefinition of Principal terms used in Naval Architecture
Lines PlanLines Plan. . The delineation of the ship's form in three views:The delineation of the ship's form in three views:
The longitudinal elevation or profile which gives the general The longitudinal elevation or profile which gives the general
outline of the ship, the position and sheer of the decks.outline of the ship, the position and sheer of the decks.
The half-breadth plan shows the shape of the decks and the The half-breadth plan shows the shape of the decks and the
waterlines which are formed by the intersection of the surface waterlines which are formed by the intersection of the surface
of the ship with horizontal planes.of the ship with horizontal planes.
The body plan which shows the transverse sections. The The body plan which shows the transverse sections. The
lines plan represents the moulded surface of the ship, that is lines plan represents the moulded surface of the ship, that is
the inside of shell plating. The accepted convention for the the inside of shell plating. The accepted convention for the
profile is to show the bow pointing to the right.profile is to show the bow pointing to the right.

12. SHIP MOTIONSSHIP MOTIONS
Understanding the terms like Understanding the terms like
Heaving, Pitching Surging, Rolling, Yawing, etcHeaving, Pitching Surging, Rolling, Yawing, etc..
Heave
z

13. 2.2 Nomenclature for typical hull structures2.2 Nomenclature for typical hull structures
1 Strength deck 1 Strength deck
platingplating
16 Side shell longitudinals16 Side shell longitudinals
2 Stringer plate2 Stringer plate17 Longitudinal bulkhead 17 Longitudinal bulkhead
platingplating
3 Sheer strake3 Sheer strake 18 Longitudinal bulkhead 18 Longitudinal bulkhead
longitudinals longitudinals
4 Side shell 4 Side shell
platingplating
19 Inner bottom plating19 Inner bottom plating
5 Bilge plating5 Bilge plating 20 Inner bottom longitudinals20 Inner bottom longitudinals
6 Bottom shell 6 Bottom shell
PlatingPlating
25 Deck transverse centre 25 Deck transverse centre
tanktank
7 Keel plate7 Keel plate 26 Bottom transverse centre 26 Bottom transverse centre
tanktank
8 Deck 8 Deck
longitudinallongitudinal
27 Deck transverse wing tank27 Deck transverse wing tank
9 Deck girders9 Deck girders 28 Side shell vertical web28 Side shell vertical web
10 Sheer strake 10 Sheer strake
longitudinallongitudinal
29 Longitudinal bulkhead 29 Longitudinal bulkhead
vertical webvertical web
11 Longitudinal 11 Longitudinal
bulkhead top bulkhead top
strakestrake
30 Bottom transverse wing 30 Bottom transverse wing
tank tank
12 Bottom 12 Bottom
longitudinalslongitudinals
31 Cross ties31 Cross ties
13 Bottom 13 Bottom
girdersgirders
32 Transverse web face plate32 Transverse web face plate
14 Bilge 14 Bilge
longitudinalslongitudinals
33 Double bottom floor33 Double bottom floor
15 Longitudinal 15 Longitudinal
bulkhead lower bulkhead lower
strakestrake
36 Hatch coamings36 Hatch coamings
Figure 2: Single Hull Oil / Ore Carrier —
Typical Transverse Section

14. Fig 5: Single Skin Bulk Carrier-Fig 5: Single Skin Bulk Carrier-
Typical Cargo Hold StructuralconfigurationTypical Cargo Hold Structuralconfiguration

15. Figure 6: Single Skin Bulk Carrier — Typical Transverse SectionFigure 6: Single Skin Bulk Carrier — Typical Transverse Section

16. Figure 7: Bulk Carrier — Typical Transverse Watertight BulkheadFigure 7: Bulk Carrier — Typical Transverse Watertight Bulkhead