Shinano

Shinano (信濃) was an aircraft carrier of the Imperial Japanese Navy, converted from the incomplete hull of the third Yamato-class battleship. Her keel was laid down on 4 May 1940 at Yokosuka Naval Arsenal as battleship hull number three, intended to be a sister ship of Yamato and Musashi. Following Japan's catastrophic loss of four fleet carriers at the Battle of Midway in June 1942, the IJN ordered her conversion into an aircraft carrier to partially offset those losses.

As completed, Shinano displaced 65,800 tons standard (69,151 tons normal load), making her the largest aircraft carrier ever constructed at that time — a record she would hold until the commissioning of USS Forrestal in 1955. Her design philosophy differed markedly from other Japanese carriers: rather than a conventional fleet carrier, she was conceived as a heavily armored support carrier, intended to ferry aircraft, fuel, and munitions to other fleet carriers in battle. Her flight deck was protected by 75 mm (3 in) of armor, and the ship was fitted with Yamato-class-derived belt armor along her waterline.

Shinano was launched on 8 October 1944 under great secrecy and commissioned on 19 November 1944 under Captain Toshio Abe, with a crew of 2,175 officers and men plus some 340 dockyard workers still completing fitting-out work aboard. On the night of 28–29 November 1944, she departed Yokosuka for Kure accompanied by three destroyer escorts. The move was intended to take her to the Inland Sea for the completion of her fitting-out away from the threat of U.S. air raids.

At 20:48 on 28 November, the U.S. submarine USS Archerfish (SS-311), commanded by Commander Joseph F. Enright, detected Shinano and her escorts on radar and gave chase on the surface. After a tense six-hour pursuit, Archerfish fired a spread of six Mark 14 torpedoes at about 03:15 on 29 November 1944; four hit Shinano amidships on her starboard side. Despite the carrier's enormous size, flooding spread rapidly because watertight doors had not been properly secured, damage-control training was incomplete, and many compartment fittings were not yet finished. Shinano capsized and sank at approximately 10:57 on 29 November 1944, just 17 hours after leaving Yokosuka, in approximately 4,000 meters of water. Of the roughly 2,515 people on board, 1,435 perished; the 1,080 survivors included 32 of the civilians. For this achievement, USS Archerfish received a Presidential Unit Citation.