In April 1941, United States Navy officer Marc Mitscher proposed that the Navy develop amphibious gliders with flying-boat hulls with a goal of deploying an amphibious glider force capable of delivering an entire United States Marine Corps brigade of 715 men to a hostile beachhead, the gliders to be towed by Consolidated PBY-5A Catalina amphibian aircraft. The Navy's Bureau of Aeronautics developed specifications for two types of amphibious glider, a single-hulled type which could carry 12 passengers and a twin-hulled type that could carry 24 passengers. Two companies, the Allied Aviation Corporation and the Bristol Aeronautical Corporation, received contracts to produce 100 gliders, and plans called for the procurement of 12,000 more amphibious gliders if the concept proved successful.