Sherwood Engine Cooling Pumps, Sherwood Impellers, and Raw Water Strainers The engine cooling pump is the heart of the marine engine, supplying a continuous flow of raw water to maintain temperatures consistent with the d......Sherwood Engine Cooling Pumps, Sherwood Impellers, and Raw Water Strainers The engine cooling pump is the heart of the marine engine, supplying a continuous flow of raw water to maintain temperatures consistent with the demanding engine performance. Over the years, the Sherwood raw water pump has developed a reputation of excellence in quality. Utilizing about a dozen rubber impellers, Sherwood is able to offer cooling pumps to a wide variety of applications which vary in type, flow requirements, drive mechanisms, pressures, speed, inlet restrictions, weight, and size. Today Sherwood engine cooling pumps are chosen for their performance and dependability by the most prestigious marine engine manufacturers.