page_title: Fort Drum (Philippines)
section_title: Planning and design
hierarchical_section_title: Fort Drum (Philippines) / Planning and design
caption_attribution_description: English: longitudinal section of Fort Drum, Manila Bay
context_page_description: Fort Drum, also known as "the concrete battleship", is a heavily fortified island situated at the mouth of Manila Bay in the Philippines, due south of Corregidor Island. The reinforced concrete sea fort shaped like a battleship was built by the United States in 1909 as one of the harbor defenses at the wider South Channel entrance to the bay during the American colonial period.
  It was unique among forts built by the United States between the Civil War and early World War II, both as a sea fort and in having turrets. It was captured and occupied by the Japanese during World War II, and was recaptured by the U.S. after U.S. forces ignited petroleum and gasoline in the fort, leaving it permanently out of commission. Sixty-eight Japanese soldiers perished in the blaze. It took the U.S. soldiers days before they could even go into the fortress because of the heat.
  The now-abandoned fort was named after Brigadier General Richard C. Drum, who served with distinction during the Mexican–American War and the American Civil War, and died on October 15, 1909, the year of the fort's construction.
context_section_description: The Board of Fortifications chaired by William H. Taft recommended that key harbors of territories acquired by the United States after the Spanish–American War be fortified. Consequently, El Fraile Island was fortified and incorporated into the  harbor defenses of Manila and Subic Bays.
  Initially Fort Drum was planned as a mine control and mine casemate station. However, due to inadequate defenses in the area, a plan was devised to level the island, and then build a concrete structure on top of it armed with four 12-inch (305 mm) guns in twin mounts. This was submitted to the War Department, which decided to change the 12-inch (305 mm) guns to 14-inch (356 mm) guns mounted in twin armored turrets. 
  The forward turret, with a traverse of 230°, was mounted on the forward portion of the upper deck, which was 9 ft (2.7 m) below the top deck; the rear turret, with a full 360° traverse, was mounted on the top deck. The guns of both turrets were capable of 15° elevation, giving them a range of 19,200 yards (17,600 m). Secondary armament was provided by two pairs of 6-inch (152 mm) guns mounted in armored casemates on either side of the main structure.  There were two 3-inch (76 mm) mobile AA guns on "spider" mounts for anti-aircraft defense, probably the 3-inch Gun M1918 and probably added circa 1918.
  Overhead protection of the fort was provided by a 20-foot (6.1 m) thick steel-reinforced concrete deck.  Its exterior walls ranged between approximately 25 to 36 ft (7.6 to 11.0 m) thick, making it virtually impregnable to enemy naval attack.
caption: Longitudinal section
exif: {}