EMERGENCY MAINTENANCE AND OPERATING TIPS

ON-BOARD TOOLS AND SPARE PARTS - TM-55-1930-209-14P-9-4_638

TM-55-1930-209-14P-9-4 Water Purification Barges (NSN 1930-01-234-2165) Electric Power System Manual
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ELECTROLYTIC CORROSION Corrosion can occur when two dissimilar metals are in contact in the presence of sea water. Care is taken to avoid this in the design of an engine, but different metal types are necessary. Brass or bronze pipe fittings attached to aluminum parts (for example) will result in rapid corrosion. A zinc pencil is inserted into the heat exchanger to assist in the prevention of electrolytic action. Particular care is necessary when an engine is installed in an aluminum hull. Zinc anodes can be attached to hulls where corrosion cannot be entirely avoided and specialist firms will advise on their use. Corrosion can also be caused by current leaking from the battery (and other parts of the electrical system) to the hull via the engine or metal attachments. RADIO INTERFERENCE SHIELDING Radio interference in the form of noise can be caused by the alternator, starter motor and other engine-driven equipment. In addition, many boats have electronic equipment aboard (e.g., radar) that could create radio interference. To prevent this interference, adequate shielding must be provided, if possible. Stray electronic radiation shielding is a very complex task and for severe problems it is suggested that a specialist in the field of electronics be consulted. EMERGENCY MAINTENANCE AND OPERATING TIPS If the engine stops the first thing to do is check that the fuel supply is ON. If the fuel valves or taps are all open, check the fuel level in the tank. If the engine has been run until the fuel tank is completely empty there is a very good chance that there is a lot of dirt in the fuel lines. Change the fuel filter and, after refueling, bleed the system and re-start the engine. If the engine slows down or loses power, the cause could be something wrapped around the propeller. Always check this first. Check the air intake for obstruction and the engine compartment for a good supply of air. Also, the air intake mesh may be clogged with foreign matter sucked from a dirty engine compartment. If the engine coolant boils, ease down the throttle and try to ascertain the cause. The first check is the sea cock to ensure an adequate cooling water supply. If satisfactory, check raw water pump operation, the impeller may have failed. If so, replace with the spare impeller. A spare should always be carried on board. If a serious leak occurs on a high pressure fuel pipe, disconnect and direct the flow into a can or other receptacle, and run on the remaining cylinders. DO NOT attempt to flatten and pipe because this will ruin the fuel injection pump. Leaks in low pressure fuel pipes can be temporarily repaired by the use of heavy duty adhesive tape, hose and clamps. If an auxiliary engine is required to run while the boat is beating to windward, the boat may heel (see chart) without adverse effect on the lubrication system providing the boat is righted occasionally so that the valve gear can be lubricated. Maximum Continuous Angle of Heel Heel 4.108 4.154 4.236 6.354 HT6.354 To Port 250 300 300 300 360 To Starboard 250 300 300 300 23° -64-

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