Japanese aircraft carrier Amagi

The last purpose-built Japanese carrier construction during World War II was a group of vessels based on an improved Hiryū design, but with individual units differing in detail reflecting the changing circumstances as the conflict in the Pacific approached its conclusion. Amagi was ordered, under the provisional name of #5001, as part of the Kai-Maru 5 Program of 1942. This was a massive naval construction program intended to replace losses suffered at the Battle of Midway and focused on aircraft and aircraft carriers. The ship was one of 16 Unryū-class aircraft carriers planned, although only three were completed before the end of the war.[2][Note 1]

Amagi had a length of 227.35 meters (745 ft 11 in) overall. She had a beam of 22 meters (72 ft 2 in) and a draft of 8.73 meters (28 ft 8 in). She displaced 20,450 metric tons (20,130 long tons). Her crew consisted of 1,595 officers and men.[3]

The Unryū-class carriers used the same turbines and boilers as used in the heavy cruiser Suzuya. These consisted of four geared steam turbine sets with a total of 152,000 shaft horsepower (113,000 kW) driving four shafts using steam provided by eight Kampon Type B water-tube boilers. The ship had a designed speed of 34 knots (63 km/h; 39 mph). Amagi carried 3,670 metric tons (3,610 long tons) of fuel oil which gave her a range of 8,000 nautical miles (15,000 km; 9,200 mi) at 18 knots (33 km/h; 21 mph).[3] She had two funnels on the starboard side, each angled below the horizontal. They were fitted with a water-cooling system to reduce the turbulence caused by hot exhaust gases.[4]

Amagi, capsized in Kure harbor, 1946

Amagi's keel was laid down by Mitsubishi in Nagasaki,[3] on 1 October 1942. She was launched on 15 October 1943 and completed on 10 August 1944.[2] The ship was transferred among a number of ports on the Inland Sea until she arrived in Kure in February 1945 and was ordered to be camouflaged. Her intended air group, Air Group 601, was committed to the Battle of Iwo Jima about that same time. Amagi was briefly refitted from 10 to 24 February. On 19 March, the ship was attacked by aircraft from Task Force 58 and lightly damaged by one bomb that struck the edge of the flight deck. On 13 April, the ship was permanently moored at an island in Kure harbor and extensively camouflaged.[13]

This did not prevent the aircraft from Task Force 38 from locating and attacking the ship on 24 July. She was hit twice and experienced several near-misses. A 500-pound (230 kg) bomb detonated near the rear funnel, severely damaging it, but doing little other damage aside from blowing a small hole in the starboard hull. A 2,000-pound (910 kg) bomb penetrated the flight deck and detonated in the upper hangar, between the elevators. The explosion blew a 50-meter (160 ft) section of a hangar wall overboard and the walls of the upper hangar deck were bulged and perforated multiple times. The flight deck between the elevators was bulged up and buckled for a length of 200 feet (61.0 m) and the forward elevator was dropped to the bottom of its shaft. It also blew a 25-foot (7.6 m) hole in the upper hangar deck. Fragments from the explosion penetrated into the bowels of the ship, penetrating bulkheads and decks below. Fragments from near-misses penetrated the sides of the port hull and caused the forward bomb magazine, two boiler rooms, and the aft port engine room to flood.[13]

The captain ordered the ship abandoned later in the day, and the carrier was still afloat in the evening, albeit with a slight list to port and down by the bow. Over the next couple of days, more compartments in the ship flooded and she settled on the bottom of the harbor. Another attack on 28 July hit her several more times and the resulting damage from those hits and more near-misses to port caused the ship to list further to port. This gradually increased through the next day until Amagi capsized at 10:00 on the morning of 29 July with part of her flight deck falling overboard. The losses among the ship's crew are unknown, but were supposedly light.[13]

The ship was stricken from the Navy List on 30 November[13] and salvage work began on 5 December. The holes in the ship's hull had to be sealed to pump the water out and decrease her draft. The remains of her flight deck and upper hangar could not be made watertight and were removed using dynamite. Pontoons were used to right the ship and she was refloated on 31 July 1946. The salvage job was conducted by the Hitachi Zosen facility in Kure and they scrapped the ship afterward. The job was completed by 12 December 1947.[13]

• Chesneau, Roger, ed. (1980). Conway's All the World's Fighting Ships 1922-1946. Greenwich: Conway Maritime Press. ISBN 0-85177-146-7.
• Jentschura, Hansgeorg; Jung, Dieter & Mickel, Peter (1977). Warships of the Imperial Japanese Navy, 1869–1945. Annapolis, Maryland: United States Naval Institute. ISBN 0-87021-893-X.
• Lengerer, Hans (2010a). Illustrated Record of the Transition of the Superstructures of BB Kongô Class: Introduction to CV Unryû Class. Katowice, Poland: Model Hobby. ISBN 978-83-60041-42-0.
• Lengerer, Hans (2010b). "Katsuragi and the Failure of Mass Production of Medium Sized Aircraft Carriers". In Jordan, John (ed.). Warship 2010. London: Conway. pp. 103–21. ISBN 978-1-84486-110-1.
• Silverstone, Paul H. (1984). Directory of the World's Capital Ships. New York: Hippocrene Books. ISBN 0-88254-979-0.
• Stille, Mark (2005). Imperial Japanese Navy Aircraft Carriers 1921–1945. New Vanguard. 109. Oxford, UK: Osprey Publishing. ISBN 1-84176-853-7.
• Tully, Anthony P. (2004). "IJN Amagi: Tabular Record of Movement". Kido Butai. Combinedfleet.com. Retrieved 23 October 2011.
• Warships of the Imperial Japanese Navy: Shokaku Class, Soryu, Hiryu, Unryu Class, Taiho (PDF). Kojinsha. 6.

• Ugaki, Matome (1991). Goldstein, Donald M.; Dillon, Katherine V (eds.). Fading Victory: The Diary of Admiral Matome Ugaki, 1941–1945. Masataka, Chihaya (translator), Prange, Gordon W. (foreword). Pittsburgh, Pennsylvania: University of Pittsburgh Press. ISBN 0-8229-3665-8.