Harbor Defenses of Manila and Subic Bays
The Harbor Defenses of Manila and Subic Bays ("Coast Defenses of Manila and Subic Bays" until 1925) were a Harbor Defense Command, part of the Philippine Department of the United States Army prior to and during World War II.
Background and construction
The Board of Fortifications chaired by William H. Taft recommended that key harbors of territories acquired after the Spanish–American War be fortified. Accordingly, El Fraile, Carabao, Corregidor, Grande, and Caballo Islands in the Philippines were to be fortified and incorporated into the harbor defenses of Manila and Subic Bays, protecting the bases of the US Asiatic Fleet and the Philippines Territory's capital and chief port of Manila.
The harbor defenses during World War II
In July 1941 these units were commanded by Major General George F. Moore, whose Philippine Coast Artillery Command was headquartered at Fort Mills, on Corregidor. This command included Fort Hughes (Caballo Island), Fort Drum (El Fraile Island), and Fort Frank (Carabao Island) at the entrance to Manila Bay, as well as Fort Wint (Grande Island) at the entrance to Subic Bay. At this time there were 4,967 troops assigned to the Harbor Defenses.
Harbor defense units were heavily engaged against the Japanese invasion in 1941–42, particularly Battery Way and Battery Geary on Corregidor, as well as Fort Drum. However, the coast defense installations were vulnerable to air and high-angle artillery attack, and Corregidor and the remaining US and Filipino forces surrendered on 6 May 1942.
Chief of Coast Artillery Major General Joseph A. Green had recommended reassigning elements of the Harbor Defenses to anti-aircraft duty, but this proposal was rejected. The War Department had been intending to send three additional AA regiments and two brigade headquarters, however this was not accomplished before the Japanese invasion in December 1941.