A closed cooling system on a boat is one in which the engine is cooled by water that is circulated through the engine using a pump. The water is then returned to a holding tank or directly back into the body of water from whence it came. A closed cooling system provides many benefits over an open cooling system, which simply circulates water from the lake, river, or ocean in which the boat is moored directly through the engine without passing it through a holding tank first.
One of the main benefits of a closed cooling system is that it prevents saltwater and other contaminants from entering and damaging the engine. It also helps to prolong the life of engine components by circulating clean water through them rather than exposing them to potentially corrosive saltwater. Additionally,closed cooling systems are typically more efficient than open systems since they lose less heat to their surroundings. This can be especially beneficial in cold weather conditions when you want your engine to operate at peak efficiency.