Steering gear , mechanical steering wheel

Steering gear

1. King Abdul-Aziz University Faculty of Maritime Studies Marine Engineering department Introduction to Marine Engineering (MSE 389) Lecture 7. Steering gears 1

2. Introduction A Steering Gear is the equipment provided on ships to turn the ship to left (Port side) or to right (Starboard side) while in motion during sailing. The Steering Gear works only when the ship is in motion and, does not work when the ship is stationary. All the ships are to be provided with, an efficient main steering gear, an auxiliary steering gear and, except for very small ships, the main steering gear should be power operated. 2

3. Steering System General Arrangement 3

4. Steering System 4

5. Steering gear in steering gear compartment 5

6. 6 Steering Gear System The steering gear system has three main parts: Control equipment Power unit Transmission system to the rudder stock. In brief, the operation of the steering gear can be explained as - With the help of the control system, a signal of desired rudder angle is sent from the bridge. This signal activates the power unit with which the rudder is attached. The rudder moves with the help of the power unit till the right angle is reached.

7. Steering gear system requirements According to an international legislation , all the ships must have two independent power units , one as the main power unit and the other as auxiliary. In case , the ship has two identical power units, then there is no need for an auxiliary unit. 7 Moreover, each power unit should be capable of transmitting a torque that swings the rudder from 35 degree on one side to 35 degree on the other side, while the ship is moving at the full speed. It is also to be noted that this whole process shouldn't take more than 28 seconds. 30

8. 8 Steering gear system arrangements The whole steering gear arrangement should be kept in a separate compartment, known as the steering gear compartment/room. Both the steering gear systems should be connected to the bridge and operated from the same. The system should be such designed that in case of failure of one, the changeover to the other system should be automatic and within 45 seconds. Proper audible and visual alarms should be provided in case of failure of any part.

9. 9 Steering gear system arrangements Most of the steering gears found on ships have hydraulically operated equipment known as telemotor. This telemotor can also be electrically operated. The system is also provided with pumps to quickly supply hydraulic fluid to the rudder. All the pumps are quick-repose pumps, and as the signal from the bridge does not allow enough time for the pump to switch on and off, a continuously running pump is required. Usually Variable displacement pumps are used for this purpose.

10. 10 Steering Gear System Steering gears can be arranged with hydraulic control equipment known as a 'telemeter', or with electrical control equipment. The power unit may in turn be hydraulic or electrically operated.

11. Types of steering gear systems Manually operated, Mechanical Steering Gears Fully hydraulic type Electro-hydraulic type Fully electric type 11

12. Manually operated steering gear 12

13. Electro hydraulic 13

14. Electro steering 14

15. 15 Fully hydraulic type Power units Two types of hydraulically powered transmission units or steering gear are in common use, the ram and the rotary vane. Ram type Two particular variations, depending upon torque requirements, are possible the two-ram and the four-ram. A two-ram steering gear is shown in Figure.

16. Four and two rams hydraulic steering gear 16

17. Two ram steering system 17

18. 18 Assignment # 7 W h a t a r e the m ain c o m p one n ts o f ship S t e e rin g Gear System? W h a t a r e the m ain r equ i r e m e n ts f or ship S t e e ri n g g e ar system according to the IMO regulations? What are the main types of ship steering gear systems? Explain with drawing the operations of the four and two rams hydraulic steering gear systems for ships?