Army amphibian units gave MacArthur a personal fleetof gators that helped him return to the Philippines.
When the United States entered World War II, the military had many questions about how best to organize and employ amphibious forces. The Navy, stretched to meet its worldwide obligations, at first welcomed an offer from the Army to operate its own amphibious craft. In May 1942, the War Department directed Lieutenant General Brehon B. Somervell, commanding the Services of Supply, to establish the Engineer Amphibian Command.
Forces were organized in engineer amphibian brigades—later redesignated engineer special brigades (ESBs)—each with 7,300 officers and men and 750 landing craft. A brigade included three engineer boat and shore regiments (EBSRs), each composed of one boat and one shore battalion plus supporting units. Boat crews would deliver men and equipment to invasion beaches while the shore engineers loaded and unloaded cargo, prepared the beaches, and established supply dumps. The engineers also would be ready to defend their shores against enemy counterattack.