Fort Drum (El Fraile Island)

Fort Drum (El Fraile Island), also known as the “concrete battleship,” is a heavily fortified island fortress situated at the mouth of Manila Bay in the Philippines, due south of Corregidor Island. It was occupied by the Japanese in World War II, and was recaptured by the U.S. after igniting oil and gasoline in the fort, leaving it permanently out of commission. Fort Drum was named for Brigadier General Richard C. Drum.

Planning and Design
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, 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 two twin 12 inch guns. This was submitted to the War Department, which decided to change the 12 inch guns to 14 inch guns mounted in twin armoured turrets. The forward turret, with a traverse of 230°, was mounted on the forward portion of the top deck, which was 9 feet 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. Secondary armament was to be provided by two pairs of 6 inch guns mounted in armoured casemates on either side of the main structure. There were two 3 inch mobile AA guns on "spider" mounts for anti-aircraft defense. Overhead protection of the fort was provided by a 18ft. thick steel-reinforced concrete deck. The exterior concrete walls of the fort were to be 25 to 60 ft.

Construction
Construction began in April 1909 and lasted five years while the island was leveled by U.S. Army engineers and then was built up with thick layers of steel-reinforced concrete into a massive structure roughly resembling a concrete ship, 350 feet long, 144 feet wide, and with a top deck 40 feet above water at mean low tide. The 14 inch M1909 guns and their two custom built turrets, dubbed Batteries Marshall and Wilson, were delivered and installed by 1916. The secondary 6 inch M1908MII guns, batteries Roberts and McCrea, were installed the same year. Searchlights, anti-aircraft batteries, and a lattice-style fire control tower were mounted on the fort's upper surface. The living quarters for the approximately 240 officers and enlisted men along with the power generators, plotting rooms and ammunition magazines were located deep inside the fort.

Philippines Campaign (1941–1942)
The successful invasion of Luzon by the Japanese Imperial Army in late December, 1941 quickly brought land forces within range of Fort Drum and the other Manila Bay forts. Just before the outbreak of war in the Pacific on 7 December 1941, Fort Drum had been restaffed with men and officers of the 59th Coast Artillery Regiment (E Battery). The wooden barracks located on the fort's deck were dismantled to provide an unobstructed field of fire for Battery Wilson. On 2 January 1942, Fort Drum withstood heavy Japanese air bombardment. On 12 January 1942, a Model 1906 3 inch seacoast gun with a pedestal mount was installed at Fort Drum to help protect the fort's vulnerable "stern" section from attack; this weapon was known as Battery Hoyle, and on 13 January 1942—before the concrete emplacement was fully dry or the gun had been bore-sighted or checked for assurance level—became the first American battery of seacoast artillery to open fire on the enemy in World War II when it drove off a Japanese-commandeered inter-island steamer apparently bent on a close inspection of Fort Drum's heretofore vulnerable rear approach (the cage mast control tower masked the fire of the rear main turret, while the height of the gun above water created a dead space even had the field of fire been clear).

The first week of February 1942 saw the fort come under sustained fire from Japanese 150mm howitzer batteries positioned on the mainland near Ternate. By the middle of March the Japanese had moved heavy artillery into range, opening fire with 240mm siege howitzers, destroying Fort Drum's 3-inch antiaircraft battery, disabling one of the 6-inch guns, and damaging one of the armored casemates. Sizeable portions of the Fort's concrete structure were chipped away by the shelling. The armored turrets were not damaged and remained in service throughout the bombardment. Counter-battery fire from Fort Drum's 14-inch guns and Fort Frank's 12-inch mortars was ineffective. With the collapse of American and Filipino resistance on Bataan on 10 April, only Fort Drum and the other harbor forts remained in U.S. hands.

On the night of 5 May the 14-inch batteries of Fort Drum opened fire on the second wave of the Japanese forces assaulting Corregidor, sinking several troop barges and inflicting heavy casualties. Fort Drum surrendered to Japanese forces following the fall of Corregidor on 6 May 1942 and was subsequently occupied by them until 1945. No U.S. personnel on Fort Drum were killed during the siege and only five were injured. The surrender of the Manila Bay forts marked the end of U.S. resistance in the Philippines.

Philippines Campaign (1944–1945)
In 1945, as part of the offensive to recapture Manila, Fort Drum was assaulted by US forces. After a heavy aerial and naval bombardment, US troops gained access to the deck of the fort on 13 April, and were able to confine the garrison below. Rather than attempting to break in, the troops and engineers adapted the solution first used some days earlier in the assault of mortar forts on Fort Hughes.

There, the troops "pumped two parts diesel oil and one part gasoline" into mortar pits, stood off, and ignited it with tracer bullets. At Fort Drum a similar technique was employed, utilizing air vents on the top deck, but a timed fuse was used rather than tracer fire.

On ignition, the remaining Japanese were annihilated; the flammable mixture kept a fire burning in the fort for several days. With the bay forts, including Fort Drum, thus neutralized, Japanese resistance in the Manila Bay area was ended. The ruins of Fort Drum, including its disabled turrets and 14 inch guns, remain at the mouth of Manila Bay.