UNITED STATES ARMY
57th COAST ARTILLERY REGIMENT (GUN) (MOBILE)
BATTERY GUIDONS • 1941The mobile gun regiments of the US Army Coast Artillery Corps embodied three battalions, each with 8 x 155mm guns in two batteries, tractor towed. Each battery also had 4 x caliber .50 machine guns on antiaircraft mounts The 155mm gun was the M1918 GPF (Grande Puissance Filloux). Grande Puissance means high-power, and Filloux was the last name of the gun's designer. The GPF was a French weapon that had been adopted by the US Army in World War I and was manufactured under licence in the United States, remaining in production until the mid-1920s. There were nearly a thousand GPFs on hand in 1940, and those not assigned to mobile gun regiments were used to augment the fixed defenses of American ports and naval bases. In 1942, the GPF began to be replaced by the more modern US-designed 155mm Gun M1, though it remained in service up to 1945. The mobile gun regiments also had a separate searchlight battery with 12 x 60in searchlights.In 1941, the mobile gun regiments were mostly assigned to the fixed harbor defense organizations in the continental US and its overseas territories, But later in the war many were sent overseas, primarily to the Pacific theater of operations, where they served as base defense units and conventional field artillery. When the Army adopted the flexible group organization in mid-1943, some though not all CA regiments were reorganized accordingly. Their regimental headquarters and headquarters batteries became separate group HHBs and their subordinate battalions were renumbered as separate battalions. On 7 December 1941, the 57th Coast Artillery Regiment was assigned to the 3rd Coast Artillery District, Harbor Defenses of the Chesapeake Bay, First Army/Northeastern Defense Command.
