Overview The United States acquired the Philippines as a territory as a result of the Spanish–American War in 1898. The Taft board of 1905 recommended extensive, then-modern fortifications at the entrance to Manila Bay. The islands there had been declared military reservations on 11 April 1902. Construction soon started and the forts were substantially complete by 1915 as the Coast Defenses of Manila and Subic Bays (renamed Harbor Defenses in 1925).Berhow 2015, p. 430 All of them were on islands at the mouth of the bay, except Fort Wint on Grande Island in Subic Bay. As the only large island of these, Corregidor had more gun batteries than the others, along with barracks, other garrison buildings, and facilities for controlling two underwater minefields. Corregidor also had 13 miles of electric railway, an unusual feature in US forts.Morton, p. 473 The forts were designed for one purpose: to prevent enemy surface vessels from entering Manila Bay or Subic Bay. They were designed before airplanes became important in war, and (except for Fort Drum) were vulnerable to air and high-angle artillery attack, being protected only by camouflage. Except for the mortar batteries, the turrets of Fort Drum, and the two guns of the 1920s Batteries Smith and Hearn, the forts' guns had restricted arcs of fire of about 170°, and could only bear on targets entering the bay from the west.
Overview The United States acquired the Philippines as a territory as a result of the Spanish–American War in 1898. The Taft board of 1905 recommended extensive, then-modern fortifications at the entrance to Manila Bay. The islands there had been declared military reservations on 11 April 1902. Construction soon started and the forts were substantially complete by 1915 as the Coast Defenses of ,Manila and Subic Bays (renamed Harbor Defenses in 1925).Berhow 2015, p. 430 All of them were on islands at the mouth of the bay, except Fort Wint on Grande Island in Subic Bay. As the only large island of these, Corregidor had more gun batteries than the others, along with barracks, other garrison buildings, and facilities for controlling two underwater minefields. Corregidor also had 13 miles of electric railway, an unusual feature in US forts.Morton, p. 473 The forts were designed for one purpose: to prevent enemy surface vessels from entering Manila Bay or Subic Bay. They were designed before airplanes became important in war, and (except for Fort Drum) were vulnerable to air and high-angle artillery attack, being protected only by camouflage. Except for the mortar batteries, the turrets of Fort Drum, and the two guns of the 1920s Batteries Smith and Hearn the forts' guns had restricted arcs of fire of about 170°, and could only bear on targets entering the bay from the west.