PUMP GP-WATER 5S6684 - Caterpillar

A completely separate sea water system should be provided for each engine to prevent a blockage resulting in the need to shut down more that one engine.The water intake fitting should not project appreciably below the bottom of the hull and it should be situated well clear of other components such as shafts, logs, rudders to prevent flow problems at high speeds.The intake fittings and pipework should have a minimum bore of 25mm (1") (A). Inboard of the intake fitting a sea cock must be provided. This should be of the full flow type giving unobstructed passage to the water in the open position, with a minimum bore of 25mm (1").Between the intake fitting and the sea water pump on the engine, there should be a strainer which should be easily accessible for routine examination, and should be easily removable.From the sea water strainer a pipe should be run to the sea water pump inlet connection on the engine (see figure A). The pipe may either be mainly rigid, of for example copper or cupro-nickel, or flexible, but only flexible hose which is reinforced to prevent collapse should be used. Rubber hose connections in the sea water system should be kept as short as possible and should be reinforced with a minimum of three layers of canvas. The system must be sufficiently flexible to permit the engine to move on its flexible mountings. The sea water pump connection is for hose with a 32mm (1.25") bore.Care should be taken to use compatible materials in the sea water systems, to prevent excessive galvanic corrosion. Systems incorporating copper, cupro-nickel, stainless steel Type 316, gun-metal, silver solder, and aluminium brass will generally be satisfactory. Components made from lead, iron steel, aluminium or its alloys, zinc or magnesium, should be generally avoided.A typical system is shown in figure (A). Where possible mount the strainer so that the top is just above the waterline to facilitate cleaning.Keel Cooling or Skin Cooling
Keel cooling or skin cooling is a closed circuit method of cooling that uses only coolant with 50/50 antifreeze mix.A properly designed and installed cooling system is essential for satisfactory engine life and performance.Keel cooling is a cooling system that uses a group of tubes, pipes or channels attached to the outside of the hull below the waterline as a heat exchanger. Keel coolers are used in preference to the standard raw water cooled engine mounted heat exchanger when operating in areas that have heavy silt and debris in the water that would erode the heat exchanger tubes or block them.Keel cooling is used in Arctic conditions to avoid the problems of freezing that is experienced with the raw water circuit on the heat exchanger cooling system.Keel coolers are available in standard designs from several manufacturers. These units are simple to install and are sized by the manufacturer for the engine model and boat application. Commercial coolers are made of erosion resistant materials and have a relatively high heat transfer efficiency.The disadvantage of