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 TM 55-1905-223-10
f. Power Takeoff. The engine transfers power to the bowthruster waterjet and auxiliary fire pump
through twin-disk marine drive reduction gears. Each marine drive clutch is pneumatically operated via a
control located on the PHC. Each marine drive utilizes self-contained lubrication.
1-19. Bowthruster Waterjet System. The bowthruster waterjet system is a propulsion and steering system
located at the bow and used in combination with the ship's main propulsion system to give the LCU added
maneuverability. A high volume jet pump driven by the bowthruster/auxiliary fire pump diesel engine is the
propulsion element. Throttling the engine increases or decreases the thrust force. Twin hydraulic steering
motors point the jet nozzle to any desired relative bearing, controlling thrust angle. Displacement of seawater
in a given direction generates an equal recoil force in the opposite direction, moving the bow of the LCU as
needed. Control of the bowthruster waterjet is from the PHC by the bowthruster control panel. The bowthruster
control panel provides controls for starting and stopping the electric and hydraulic units, steering the nozzle,
and silencing the alarm horn. The panel also contains indicator lamps for electric and hydraulic units running,
minimum hydraulic oil tank and minimum lubricating oil tank levels, and a thrust direction indicator.
1-20. Bow Anchor Windlass System. The bow anchor windlass system is a hydraulic driven chain windlass
for handling the LCU's bow anchors and stud link anchor chain. The system consists of two port and two
starboard bow 'anchor windlass assemblies, hydraulic power pack assemblies, and directional control valves.
The windlass is controlled from a bow control box located adjacent to each windlass on the forecastle deck.
The bow control box contains controls for starting and stopping the hydraulic power pack and hauling in or
paying out the windlass. Each windlass has a single wildcat for anchor chain handling and gypsy catheads on
each-end for rope handling. The hydraulic power pack provides hydraulic pressure for the directional control
valve which controls the direction of the wildcat, which in turn hauls in or pays out anchor chain. Auxiliary
clutches transfer power to the outboard and inboard gypsies. The unit contains a spring loaded failsafe brake
system; hydraulic pressure is required to release and to hold off the brake. Any function which reduces
hydraulic pressure below the release pressure of the brake will cause brake application. A hand brake is
provided for manually braking the windlass. The electro-hydraulic power unit for the port windlass is located in
the forward area of the bowthruster room, and the starboard windlass power unit is located in the forward
inboard side of the boatswain storeroom.
1-21. Bow Ramp System. The bow ramp system provides a means of lowering and raising the bow ramp.
The system consists of a hydraulic power pack, a winch assembly, and ramp lifting assemblies.
a. Hydraulic Power Pack. The hydraulic power pack provides power to the winch assembly. The power
pack consists of an electric motor, drive coupling, hydraulic pump and fluid reservoir tank, and associated
pipes, valves, and gauges. The hydraulic power pack is located in the boatswain's storeroom.
b. Winch Assembly. The winch assembly takes in or pays out wire rope for raising or lowering the bow
ramp. The assembly consists of a hydraulic motor, hydraulic failsafe brake, drum, slack wire limit switch, and
emergency hand crank. The winch assembly is located in the boatswain's storeroom adjacent to the hydraulic
power pack.
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