Aircraft Carrier Akagi

Akagi (赤城, "Red Castle") was the flagship of the Imperial Japanese Navy's Kido Butai (機動部隊, Mobile Strike Force) — the most powerful carrier task force assembled up to that point in history. Her name derives from Mount Akagi in Gunma Prefecture, she was named as a battlecruiser, and IJN battlecruisers were named after mountains.

Akagi was originally laid down on December 6, 1920, at Kure Naval Arsenal as the second ship of the Amagi-class battlecruisers under the "Eight-Eight Fleet" expansion program. The Washington Naval Treaty of 1922 limited capital ship construction, but specifically permitted the conversion of two incomplete battlecruiser hulls into aircraft carriers. When the primary candidate, Amagi, was too severely damaged by the Great Kanto Earthquake of September 1923 to be repaired economically, Akagi's conversion was substituted. She was launched as a carrier on April 22, 1925, and commissioned on March 25, 1927.

In her initial configuration, Akagi featured an unusual triple-deck arrangement with three flight decks of different lengths. Between 1935 and 1938, she underwent a comprehensive reconstruction at Sasebo Naval Arsenal: the three decks were consolidated into a single enlarged 249-meter flight deck; the hangars were extended forward; an island superstructure was added on the port side (one of only two Japanese carriers with a port-side island, the other being Hiryū); anti-aircraft armament was increased; and her aircraft capacity was raised to 91 aircraft. After reconstruction, her standard displacement rose to 36,500 long tons, making her one of the largest carriers in the world at the time.

Akagi served as Vice Admiral Chuichi Nagumo's flagship for the Pearl Harbor strike force. On December 7, 1941, the Kido Butai, positioned 230 nautical miles north of Oahu, launched 353 aircraft in two waves. Akagi's air group contributed 27 B5N torpedo bombers and 9 A6M Zero fighters in the first wave, and 18 D3A dive bombers in the second. The attack sank or damaged much of the U.S. Pacific Fleet's battleship force, though the American carriers were absent. Akagi subsequently participated in operations across the Indian Ocean and against Darwin, Australia, in early 1942.

At the Battle of Midway on June 4, 1942, Akagi was caught in a critical moment of vulnerability — her flight deck crowded with armed and fueled aircraft being re-spotted for a second strike against Midway Island. Three Douglas SBD Dauntless dive bombers from USS Enterprise, led by Lieutenant Commander Dick Best, attacked Akagi. Best's bomb struck near the midship elevator, detonating among the torpedo- and bomb-laden aircraft on the hangar deck. The resulting fires and secondary explosions made her impossible to save. After the crew abandoned ship, she was scuttled early on June 5, 1942, by torpedoes from the destroyers Arashi, Hagikaze, Maikaze and Nowaki. Of her crew of approximately 1,630, some 267 were killed (the Japanese battle report gives 221) — the fewest fatalities among the four Japanese carriers lost at Midway. The loss of Akagi, Kaga, Soryu, and Hiryu — along with their experienced air groups — was an irreversible strategic blow from which the Imperial Japanese Navy never recovered.

The wreck of Akagi was located in October 2019 by the research vessel Petrel, resting at a depth of about 18,000 feet (5,490 m) in the Pacific Ocean northwest of Midway Atoll. In September 2023, the EV Nautilus conducted a photogrammetric survey of the wreck, confirming the ship largely intact despite heavy damage to the hull, superstructure and flight deck.