Boat Engine Cooling Systems

Written by Dina Kayed
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There are basically three ways of cooling a boat engine. A cooling system will be chosen for each boat depending on its size and required performance. Not knowing enough about your marine engine and how it works could cause problems in the long run. Neglecting the fact that your boat's cooling system might not be cooling sufficiently could easily burn your engine away.

Cooling Systems

The first and original method of cooling is a raw water cooling system. This means using the very water the boat is sailing on for cooling the engine. The water may be salty or fresh; it doesn't make a lot of difference really, except that salty water is more corrosive than fresh. This cooling method is not at all satisfactory for big boats; it is a second or third choice for small boats.

The raw cooling system works by pumping sea water through the engine, and then out through the exhaust. This is not a satisfactory way to cool your engine, because within a very short time, the water coming into contact with the metal will ruin it. Salty water, especially, will cause it to rust. Scale build up is another problem that is associated with a raw cooling system. Scale hinders the water flow and eventually the engine overheats.

The best method of cooling an engine is a fresh water cooling system. This is a closed system that does not use raw sea water for cooling. It uses antifreeze and is thus more efficient and a lot less corrosive. It can be used for high speed boats and will not rust the engine. The final kind of cooling system is keel cooling. This method is not used much because it only works on very small boats or those that sail in very shallow water.


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