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The Forward Engine Room

Glenn L. Duncan

Welcome to the Forward Engine Room. You have entered the engine room from the After Battery Compartment. The Forward Engine Room contains: Two Fairbanks Morse, Main Engines and Generators, two Badger Evaporators, the boat ventilation Supply Blower, Exhaust Blower and Damper box. Two Hardie Tyne, 3000 psi, High Pressure Compressors, Clean Fuel Oil Storage Tank, Lube Oil Storage Tank, and fuel and lube oil centrifuges. Instrumentation and control panels for each engine.

Along each side of the engine room walking deck is the top of #1 and #2 Main Engines. These engines are 12 cylinder, Fairbanks Morse, 1600 Horse Power, Opposed Piston (two pistons per cylinder, one over and one under) engines. They are each direct connected to individual electrical generators. The engines and generators can be connected electrically to the propulsion motors for propulsion when surfaced, or any two generators to the propulsion motors when submerged and snorkeling. Another purpose for the engines is to recharge the batteries when low in charge. When surfaced there are many engine combinations. Four on propulsion, two on battery charge two on propulsion, one on charge and three on propulsion. When snorkeling, the combination would be two on propulsion, or one on propulsion and one on charge. Each engine has a control panel with instrumentation, and at the # 1 control panel are the hydraulic control levers for all engine hydraulic operated snorkel and normal outboard exhaust valves. The exhaust from each engine goes through an inboard manually operated gate valve, located in the exhaust header, before penetrating the hull in the overhead. The large hand wheel for the inboard exhaust valve takes 32 turns to open and close the valve. Engine air is provided by a 36 " hydraulic operated (Operated from the control room) mushroom Main Induction valve, located in the sail behind the conning tower. This valve is connected to the engine rooms by piping in the superstructure that connects at the hull with a 22" manually operated flapper valve. Outside air enters the engine room through a 22" quick release flapper valve in the center of the overhead. The air is ducted to outside the engines to direct any water that come into the engineroom, through the air induction, to the bilges.

In the overhead (ceiling) between the engine exhaust headers is the Ventilation Supply Blowerm Exhaust Blower and a damper box to direct the ventilation air flow. When on the surface the ventilation fresh air comes to the hull from the Main Induction Valve through 10" piping that connects to the ventilation intake in the engine room through a second quick release flapper valve. The supply blower is connected to ducting that connects to each compartment through a forward and after Cooling Coil and double manual flapper valves at each compartment bulkhead (wall). On the surface fresh air is drawn into the boat and distributed forward and aft to provide ventilation for all compartments. Submerged the blower inlet is shifted to the engine room and the boats atmosphere is recirculated from the engine room to all compartments. The exhaust blower is also connected to all compartments by ducting. The exhaust ducting also has manual double flapper valves at the compartment bulkheads. On the surface the exhaust blower removes air from all compartments and discharges into the engine room where the runnning engines consume the foul air and provide a slight negative pressure allowing the supply blower to be more effective supplying fresh air to the boat. Submerged the exhaust air is also discharged to the engine room for recirculation through the supply blower and cooling coils.

At the forward end of the engine room are two insulated, tank like pieces of equipment with a blower and motor on the top of each. These are the the Badger Evaporators, called stills. The two electric heated evaporators boil sea water, collect, compress and condense the steam to provide a combined 2000 gallon fresh water a day for the boat equipment and crew. These evaporators also provide the high quality water to be used to replenish the water lost from the battery cells during operations.

In the center of the engine room, between the engines and below the walking deck, are two Hardie Tyne 3000 lb air compressors. These compressors supply air to air flasks in air banks. The flasks for air bank #1 are located inside the pressure hull in the battery wells, all other air banks are located outside the pressure hull in the main ballast tanks. The air banks are connected to the air manifold in the control room where it is reduced in pressure and routed throughout the boat for engine air start, air to pressurize fresh water tanks, air to pressurize trim tanks, air to charge torpedoes, air to eject torpedoes. This manifold directs 3000 psi air for blowing emergency tanks and 600 psi normal reduction air to blow ballast tanks from the air manifold.
Aft of the compressors, in the lower level engine room , are the Lube Oil Storage Tank #1 and Clean Fuel Oil Tank #1.

As you proceed to the After Engine Room, there are two centrifuge by the door, that clean Engine Lube Oil and Engine Fuel Oil by centrifigual force. In a barrel rotating at 16,000 rpm the Fuel Oil centrifuge separates water and fuel carried over from the fuel tanks. The clean fuel is then pumpeed to the clean fuel to the storage tank. The Lube Oil centrifuge separates suspended carbon and other impurities from the oil that are picked up during the pass through the engine.