A complete guide to Deck Machineries in ship

DECK MACHINERY

WEIGHT-HANDLING EQUIPMENT

To qualify for advancement in rating, you must be familiar with the construction, operation, and maintenance of anchor windlasses, winches, capstans, and cranes. 

Anchor Windlasses

• In an electro hydraulic mechanism, one constant-speed electric motor drives two variable-stroke pumps through a coupling and reduction gear. Other installations include two motors, one for driving each pump. Each pump normally drives one wildcat.
• However, when a cross-connect valve is used, either pump may drive either of the two wildcats.
• The hydraulic motors drive the wildcat shafts with a multiple-spur gearing and a locking head.
• The locking head allows the operator to disconnect the wildcat shaft and permit free-wheeling operation of the wildcat when dropping anchor.
• Each windlass pump is controlled either from the weather deck or windlass room. The controls are hand wheels on shafting leading to the pump control. The hydraulic system will require your attention.
• Be certain the hydraulic system is always serviced with the specified type of clean oil.
• You may have to maintain two types of anchor windlasses-electric and electro hydraulic. In an electro hydraulic windlass, your principal concern is the hydraulic system.

• A windlass is used intermittently and for relatively short periods of time. However, it must handle the required load under severe conditions. This means you must maintain and adjust the machinery when it is not in use. This practice will prevent deterioration and ensure windlass reliability.
• Windlass brakes must be kept in satisfactory condition if they are to function properly.
• Wear and compression of brake linings will increase the clearance between the brake drum and band after a windlass has been in operation.
• Brake linings and clearances should be inspected frequently. Adjustments should be made according to the technical manual for the equipment.

Follow the lubrication instructions listed on applicable maintenance requirement cards (MRCs).

• If a windlass has been idle for some time, it should be lubricated. Lubrication protects the finished surfaces from corrosion and prevents seizure of moving parts.

The hydraulic transmission of electro hydraulic windlasses and other auxiliaries are manufactured with close tolerances between moving and stationary parts.

• Use every precaution to keep dirt and other abrasive material out of the system. When the system is replenished or refilled, use only clean oil. Filter the oil as you pour it into the tank. If a hydraulic transmission has been disassembled, clean it thoroughly before reassembly. Before installing piping or valves, clean their interiors to remove any scale, dirt, preservatives, or other foreign matter.

Winches:

Winches are used to heave in on mooring lines, to hoist boats, as top lifts on jumbo booms of large auxiliary ships, and to handle cargo. Power for operating shipboard winches is usually furnished by electric motors. Sometimes delicate control and high acceleration without jerking are required, such as for the handling of aircraft. Electro hydraulic winches are usually installed for this purpose. Most auxiliary ships are equipped with either electro hydraulic or electric winches.

CARGO WINCHES.-

Some of the more common winches used for general cargo handling are the double-drum, double-gypsy and the single-drum, single-gypsy units. Four-drum, two-gypsy machines are generally used for minesweeping.

ELECTROHYDRAULIC WINCHES.

Electro hydraulic winches (fig. 18-3) are always the drum type. The drive equipment is like most hydraulic systems. A constant-speed electric motor drives the A-end (variable-speed hydraulic pump), which is connected to the B-end (hydraulic motor) by suitable piping. The drum shaft is driven by the hydraulic motor through a set of speed reduction gears.

Electrohydraulic winch units.

Winches normally have one horizontally mounted drum and one or two gypsy heads. If only one gypsy is required, it may be easily removed from or assembled on either end of the drum shaft. When a drum is to be used, it is connected to the shaft by a clutch. (NOTE: Another word for gypsy is wanderer. The head is called a gypsy because one or two turns of ship-handling line wrapped around it will wander over the surface between the raised ends of the drum-shaped gypsy when it is rotating. A gypsy head is NOT used to take up wire rope as is done with a rope drum, which resembles a reel used for fishing.)

ELECTRIC WINCHES.-

An electrically driven winch is shown in figure 18-4. This winch is a single-drum, single-gypsy type. The electric motor drives the unit through a set of reduction gears. A clutch engages or disengages the drum from the drum shaft. Additional features include an electric brake and a speed control switch.

CAPSTAN:

The terms capstan and winch should not be confused. A winch has a horizontal shaft, and a capstan has a vertical shaft. The type of capstan installed aboard ship depends on the load requirements and the type of power available. In general, a capstan consists of a single head mounted on a vertical shaft, reduction gearing, and a power source. Electric capstans are usually of the reversible type. They develop the same speed and power in either direction. Capstans driven by alternating current motors run at either full, one-half, or one-third speed. Capstans driven by direct current motors usually have from three to five speeds in either direction of rotation.

Maintenance of Winches and Capstans

In several respects, you will maintain a winch or a capstan in the same way you maintain a windlass. Inspect the friction brake linings regularly and replace them when necessary. Take steps to prevent oil or grease from accumulating on the brake surfaces. Periodically check the operation of brake-actuating mechanisms, latches, and pawls.

Frequently inspect winch drums driven by friction clutches for deterioration of the friction

Electric winch.

material. Check also to see if oil and grease on the surface is causing improper operation. Lubricate the sliding parts of positive clutches properly. Check the locking device on the shifting gear to see if it will hold under the rated load.

Shipboard Cranes 

Cranes used on board United States Navy ships are classified by the functional use of the crane. The following crane designations are in common use:

1. Boat and aircraft (B&A)

2. Boat and repair (B&R)

3. Boat and missile (B&M)

4. Boat and helicopter (B&H)

5. Cargo stores

Topping (king post) crane.

-Nontopping (pillar) crane.

6. Sail-service

7. Minesweeping

8. Salvage

9. Torpedo