DECK MACHINERY

(Ranger Hope © 2008, contains edits of material courtesy of A.N.T.A. publications)

CHECK YOUR PROGRESS NAME

 

1.         Describe the safety precautions necessary when working with deck machinery.

2.         Describe the maintenance requirements for anchor windlass and winches.

3.         Describe the general survey requirements of deck machinery.

4.         With the aid of a sketch, describe the basic component parts and operation of a ‘Wire and Pulley’ type steering arrangement.

5.         With the aid of a sketch, describe the basic component parts and operation of a ‘Chain and Box’ type steering arrangement.

6.         With the aid of a sketch, describe the basic component parts and operation of a ‘Push - Pull Cable’ type steering arrangement.

7.         With the aid of a sketch, describe the basic component parts and operation of a simple ‘Hydraulic’ steering arrangement.

8.         With the aid of a sketch, describe the basic component parts and operation of a steering system incorporating a telemotor.

9.         With the aid of a sketch, describe the basic component parts and operation of an electro-hydraulic steering system.

10.       Explain the problems that may be encountered with the operation of different types of steering gear and describe the remedial measures.

In the following questions, circle the most correct response.

11.       Cranes should always be marked with

            a) the vessel’s name

            b) their safe working load

            c) the manufacturer’s name

12.       Deck machinery is surveyed during

            a) initial survey

            b) periodic surveys

            c) initial and periodic surveys

13.       Cargo handling gear must comply with

            a) marine orders part 32

            b) marine orders part 42

            c) marine orders part 52

14.       One problem with a chain and box type steering arrangement is that

            a) it uses automotive parts

            b) the chain is liable to stretch

            c) it is very expensive

15.       Buffer springs are provided in a wire and pulley type steering arrangement to

            a) prevent violent recoil

            b) to gain mechanical advantage

            c) protect the hull

16.   A problem associated with hydraulic steering system is

            a) air in the system

            b) oil in the system

            c) electricity in the system

17.       Rudders should be designed to move

            a) 15 degrees port and starboard

            b) 25 degrees port and starboard

            c) 35 degrees port and starboard

18.       Rudders are inspected during

            a) annual survey

            b) two yearly survey

            c) 5 yearly survey

19.       A vessel’s steering systems should be checked

            a) within 12 hours before departure

            b) immediately after departure

            c) within 12 hours after departure

20.     Simple operating instructions of the steering system should be displayed

            a) in the engine room

            b) in the master’s cabin

                c) in the wheel house

ANSWERS

1. i    Ensure that operating and control handles are clearly marked to show ‘heave in’ and ‘pay out’ directions.

·        Never exceed the safe working load of the equipment.

·        Never operate the machinery if there is a fault in the clutch or brake.

·        Ensure that gear wheels and other moving parts are always protectively covete the machinery if you cannot sight the load.

·        Ensure that you know how to stop the running machinery in an emergency.

·        Always use the machinery in the manner specified, and within the limits suggested by the manufacturer.

2.         Maintenance should be strictly carried out as per the equipment manufacturer’s instructions. However, general guidelines for maintenance are suggested as follows:

            Weekly

·        Charge all grease points.

·        Operate clutch through full travel.

·        Operate windlass/winch.

            Six Monthly

·        Inspect clutch plates and inspect for wear and corrosion

·        Examine mechanical brake for wear.

·        Examine base and mountings for corrosion.

            In addition, check the condition of the associated wires and keep them well lubricated.

3.         The survey requirements for deck machinery are laid down in section 14 of the USL Code. After the initial commissioning survey, deck machinery is surveyed during annual and periodic surveys or as required by the appropriate authority. The surveys include the inspection  of windlass mounting and surrounding deck to insure that these are adequate for their task and have not deteriorated with use or due to corrosion. It is a requirement that the machinery should operate as specified and within safe limits.  Any gear (including cranes) used for handling cargo must comply with Commonwealth regulations contained within Marine Orders Part 32 (Cargo and Cargo Handling - Equipment Safety Measures).

4.         A wire and pulley arrangement consists of a wire wound around a drum fitted to the wheel. The wire passes through a series of pulleys on the two sides which connect to the tiller or quadrant of the rudder mechanism.To avoid excessive strain and bending of the wire the pulley blocks should be as big as possible and positioned to avoid an excessive angle or be easily fouled. Buffer springs are provided on both port and starboard to prevent violent recoil of the steering wheel. All components should be inspected and greased or oiled as appropriate.

Wire and Pulley

5.         A wide variety of chain and box installations make use of automotive parts such as shafts, universal joints and truck steering boxes. These systems require periodic inspection and lubrication. The chain is liable to stretch and should be checked regularly. For this reason the chain length is usually adjustable.

Chain and Box Gear

6.         This arrangement is similar to that used on outboard motors. The length of the cable should not be too long or short as this can affect the tiller response. If the push-pull cable or rod seizes, there must be provision for releasing the push-pull rod from the tiller to operate the emergency steering.

Push-Pull Cable Gear

7          The system operates utilising the flow of hydraulic fluid under pressure to control the movement and position of the rudder.  The system consists of a two way hydraulic pump, usually an internal gear pump, connected to the wheel. Two pipes lead from the pump to the hydraulic cylinder and ram, which in turn is connected to the tiller. The rotation of the wheel will force oil from the pump to one side of the ram thus rotating the rudder.

Simple Hydraulic System

8.   The telemotor consists of a transmitter in the wheelhouse and a receiver in the steering flat.  The movement of the wheel activates an hydraulic piston in the transmitter. The fluid displaced by this piston is used to displace a similar piston in the receiver. This movement is used to control the main steering gear’s hydraulic pump, which in turn operates the steering gear and rudder. The receiver is usually spring loaded so that the steering wheel will easily return to the midships position.

Steering Gear and Telemotor

9.         The pump supplies oil at a constant rate to a directional control valve, which is usually positioned in the steering flat.

            The valve consists of three positions, and depending on the position, will supply oil to either side of the double acting ram.  When in the neutral position, oil is locked in the ram, thus maintaining the given rudder angle, whilst the pump flow is circulated back to the tank.  The valve is operated by solenoids controlled from the wheelhouse via the control box. 

            There is a by-pass and relief valve fitted between the left and right sides of the ram.  Emergency steering can be carried out by operating the emergency steering lever located in the steering flat.

Electro-hydraulic System

10.    To avoid excessive strain and bending of the wire in a wire and pulley arrangement, pulley blocks should be as big as possible, and positioned so as not to give an excessive angle or be easily fouled.

          For chain and box, the chain is liable to stretch and should be adjustable.

          If the push-pull cable or rod seizes there must be provision for releasing the push-pull rod from the tiller to operate emergency steering.

          The main problem associated with any hydraulic system is air in the system. Most systems are therefore built to be self purging of air.

11.       b

12.       c

13.       a

14.       b

15.       a

16.       a

17.       c

18.       b

19.       a

20.       c