Reverse Reduction Gear and Clutch System.

TM 55-1915-200-10

1-10.9. Reverse Reduction Gear and Clutch System.

1-10.10.2. Air Starting System. The bow thruster

The reverse reduction gear provides power transfer from

engine air starting system provides low pressure air to a

the main engine to the propeller shaft. The system

starting motor during engine startup. When activated,

consists of a reverse reduction gear box and lubricating

the air start control valve releases air to the relay valve

oil cooling pump.

which controls the flow of air to the air starting motor.

The motor cranks the engine. The air starting system

1-10.9.1.

Reverse Reduction Gear.

The reverse

receives air from the compressed air piping system

(FIGURE 1-30).

reduction gear reduces the engine output revolutions per

minute (RPM) and reverses its direction of rotation to

1-10.10.3. Fuel System and Governor. The bow

the propeller shaft. Direction of rotation and clutch

operation are controlled by each engine's throttle control

thruster engine fuel system receives, filters, and injects

on the control consoles.

fuel into the bow thruster engine.

The governor

maintains the speed of the bow thruster engine at a

1-10.9.2.

Reduction Gear Lubricating Oil Cooling

predetermined setting and provides the means to shut

down the engine should a malfunction occur. The fuel

Pump. The reduction gear lubricating oil cooling pump

system receives fuel oil from the bow thruster day tank

cools the reduction gear cooling oil via water drawn from

via the bow thruster engine fuel oil service piping

the keel cooler. The pump is activated by a switch on

system (FIGURE 1-34). Unused fuel is returned to the

the control panel.

day tank via the bow thruster engine fuel oil service

piping system.

1-10.10. Bow Thruster Power System. The bow

thruster power system powers the bow thruster water set

1-10.10.4. Lubrication System. The bow thruster

system. The bow thruster power system consists of a

diesel engine and a marine reduction gear coupled to a

lubrication system provides lubricating oil under

right angle submersible gear box. The gear box allows

pressure to most moving parts of the bow thruster

port or starboard operation of the bow thruster water set

engine. The lubricating oil is received, filtered, cooled,

system.

and pumped through the bow thruster engine. Return oil

from the engine is routed back to the engine oil sump.

1-10.10.1.

Instrument Panel Group and Electrical

Oil is supplied to the engine oil sump via the lubrication

oil transfer system (FIGURE 1-32).

System.

The engine instrument panel group and

electrical system monitors engine operation and

1-10.10.5. Cooling System. The bow thruster cooling

provides engine controls. The instrument panel group

monitors fuel pressure, lubricating oil pressure, engine

system provides cooling water to the bow thruster

speed, and cooling water temperature via gauges. The

engines. The cooling system receives potable water

electrical system junction box monitors engine

from the bow thruster engine cooling water piping

overspeed, low lubricating oil pressure, and coolant over

system (FIGURE 1-35).

temperature indications, which will automatically cause

the fuel shutoff solenoid to cut off engine fuel. The

1-10.10.6. Marine Drive. The bow thruster receives

emergency engine stop switch, also on the junction box,

power from the bow thruster engine via the twin-disc

supplies power to the air shutoff and fuel shutoff

marine drive reduction gear and articulated shaft. The

solenoids to shut off the engine and prevent it from

articulated

being restarted.

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