The motor room is located directly below the maneuvering room. The motors run most efficiently at high speed, but propellers operate best at moderate to slow speed. So two high speed motors in a common housing are attached to each speed reduction gear. Each reduction gear in turn drives one of the two slower turning propeller shafts. For surface operation, the Elliot motors combined with the Westinghouse reduction gears developed power ranging from 20 horsepower (hp) to 2,700 hp per propeller shaft. Submerged operation developed 30 hp to 1,719 hp per propeller shaft.