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 18 ft . thick steel - reinforced concrete deck . The exterior concrete walls of the fort were to be . 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 . World War II . 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 .