Gray Marine Motor Company

For the Gray cyclecar made in Colorado, see Gray Light Car. For Gray-Dort automobiles made in Canada, see Gray-Dort Motors.
Gray Marine engine preserved at Arromanches-les-Bains, Normandy
Esmeralda II, 1947, first power boat through the Grand Canyon

Gray Marine Motor Company was a U.S. manufacturer of marine engines between 1910 and 1967. These ranged from one to six cylinders in both gas and later diesel layouts, which were used in pleasure boats, work boats, and military craft.

Gray was based in Detroit. Many fishing boats, lobsterboats, tugs and pleasure craft used Gray engines. These boats usually fell between 12 and 32 feet. Many of their engines were marinized automotive engines from Hercules, Studebaker, Pontiac, Continental, American Motors or General Motors Diesel Division.

Gray also produced a line of outboard motors. Rather than a ninety-degree gearbox, a curved housing connected motor to propeller. The lower-unit housing contained a flexible inner rotating shaft.