was one of the s built for the Imperial Japanese Navy (IJN), beginning in the late 1930s. The Yamato-class ships were the heaviest and most powerfully armed battleships ever constructed, displacing almost fully loaded and armed with nine main guns. Their secondary armament consisted of four triple-gun turrets formerly used by the s. They were equipped with six or seven floatplanes to conduct reconnaissance.
Commissioned in mid-1942, Musashi was modified to serve as the flagship of the Combined Fleet, and spent the rest of the year working up. The ship was transferred to Truk, Japan's main wartime naval base in the South Pacific theatre, in early 1943 and sortied several times that year with the fleet in unsuccessful searches for American forces. She was used to transfer forces and equipment between Japan and various occupied islands several times in 1944. Torpedoed in early 1944 by an American submarine, Musashi was forced to return to Japan for repairs, during which the navy greatly augmented her anti-aircraft armament. She was present during the Battle of the Philippine Sea in June, but did not come in contact with American surface forces. During the Battle of Leyte Gulf, Musashi was sunk by an estimated 19 torpedo and 17 bomb hits from American carrier-based aircraft on 24 October 1944. Over half of her crew was rescued. Her wreck was located in March 2015 by a team of researchers employed by Microsoft co-founder Paul Allen.
Design and description
Since the IJN anticipated it would be unable to produce as many ships as the United States, the Yamato-class ships with their great size and heavy armament were designed to be individually superior to American battleships.Garzke & Dulin, p. 45 Musashi had a length of between perpendiculars and overall. She had a waterline beam of and a draught of at deep load.Skulski, p. 10 She displaced at standard load and at deep load. Her crew consisted of 2,500 officers and ratings in 1942, and about 2,800 in 1944.Jentschura, Jung & Mickel, p. 38
The battleship had four sets of Kampon geared steam turbines, each of which drove one propeller shaft. The turbines were designed to produce a total of , using steam provided by 12 Kampon water-tube boilers, giving the ship a maximum speed of . She had a stowage capacity of of fuel oil, giving a range of at a speed of .
Armament
Musashis main battery consisted of nine 45-calibre 460-millimetre Type 94 guns mounted in three triple gun turrets, numbered from front to rear. The guns had a rate of fire of 1.5 to 2 rounds per minute.Sturton, p. 178 The ship's secondary battery consisted of twelve 60-calibre 155-millimetre 3rd Year Type guns mounted in four triple turrets, one each fore and aft of the superstructure and one on each side amidships. These had become available once the Mogami-class cruisers were rearmed with guns.Garzke & Dulin, pp. 91–92 Heavy anti-aircraft defence was provided by a dozen 40-calibre 127-millimetre (5 in) Type 89 dual-purpose guns in six twin turrets, three on each side of the superstructure. Musashi also carried thirty-six 25-millimetre (1 in) Type 96 light anti-aircraft (AA) guns in 12 triple-gun mounts, all mounted on the superstructure.Skulski, p. 20 The ship was also provided with two twin mounts for the licence-built Type 93 anti-aircraft machine guns, one on each side of the bridge.
While the ship was under repair in April 1944, the two 155 mm wing turrets were removed and replaced with three triple 25 mm gun mounts each. A total of sixteen triple 25 mm mounts and twenty-five single mounts were added at that time, giving the ship a light AA armament of 115 guns.
Armour The ship's waterline armour belt was identical to 's at thick and angled outwards 20 degrees at the top. Below it was a strake of armour that ranged in thickness from over the magazines and machinery spaces, respectively; it tapered to a thickness of at its bottom edge. The deck armour ranged in thickness from . The turrets were protected with an armour plate thick on the face, on the sides, and 270 millimetres on the roof. The barbettes of the turrets were protected by armour thick, and the turrets of the 155 mm guns were protected by armour plates. The sides of the conning tower were thick and its roof was 200 millimetres thick. Underneath the magazines were armour plates to protect the ship from mine damage. Musashi contained 1,147 watertight compartments (1,065 underneath the armour deck, 82 above) to preserve buoyancy in the event of battle damage.Garzke & Dulin, pp. 100, 104, 122
Aircraft Musashi was fitted with two catapults on her quarterdeck and could stow up to seven floatplanes in her below-decks hangar. The ship operated Mitsubishi F1M biplanes and Aichi E13A1 monoplanes and used a , stern-mounted crane for recovery.Skulski, pp. 25–26
Fire control and sensors The ship was equipped with four rangefinders, one atop her forward superstructure and one in each of her main gun turrets, and another unit atop her rear superstructure. Each gun turret was equipped with an rangefinder. Low-angle fire was controlled by two Type 98 fire-control directors mounted above the rangefinders on the superstructure. Type 94 high-angle directors controlled the 127 mm AA guns, with Type 95 short-range directors for the 25 mm AA guns.Skulski, pp. 20–21
Musashi was built with a Type 0 hydrophone system in her bow, usable only while stationary or at low speed.Skulski, p. 21 In September 1942, a Type 21 air-search radar was installed on the roof of the 15-metre rangefinder at the top of the forward superstructure. Two Type 22 surface-search radars were installed on the forward superstructure in July 1943. During repairs in April 1944, the Type 21 radar was replaced by a more modern version, and a Type 13 early-warning radar was also fitted.Hackett & Kingsepp
Construction
To cope with Musashis great size and weight, the construction slipway was reinforced, nearby workshops were expanded, and two floating cranes were built. The ship's keel was laid down on 29 March 1938 at Mitsubishi's Nagasaki shipyard, and was designated "Battleship No. 2". Throughout construction, a large curtain made of hemp rope weighing prevented outsiders from viewing construction.Garzke & Dulin, pp. 51, 53, 66Yoshimura, p. 29
Launching the Musashi also presented challenges. The ship's thick launch platform, made of nine Douglas fir planks bolted together, took two years to assemble (from keel-laying in March 1938) because of the difficulty in drilling perfectly straight bolt holes through 4 metres of fresh timber. The problem of slowing and stopping the massive hull once inside the narrow Nagasaki Harbour was met by attaching of heavy chains on both sides of the hull to create dragging resistance in the water. The launch was concealed by measures that included a citywide air-raid drill staged on launch day to keep people inside their homes. Musashi was launched on 1 November 1940, coming to a stop only further than the hull's expected travel distance across the harbour. The entry of such a large mass into the water caused a wave, which swept the harbour and local rivers, flooding homes and capsizing small fishing boats.Yoshimura, pp. 83–85, 97, 109, 115–117 Musashi was fitted out at nearby Sasebo, with Captain Kaoru Arima assigned as her commanding officer.
Towards the end of fitting out, the ship's flagship facilities, including those on the bridge and in the admiral's cabins, were modified to satisfy Combined Fleet's desire to have the ship equipped as the primary flagship of the commander-in-chief, as her sister ship Yamato was too far along for such changes. These alterations, along with improvements in the secondary battery armour, pushed back completion and pre-handover testing of Musashi by two months, to August 1942.Yoshimura, pp. 123–125
Service
Musashi was commissioned at Nagasaki on 5 August 1942, and assigned to the 1st Battleship Division, together with Yamato, and .Garzke & Dulin, p. 66 Beginning five days later, the ship conducted machinery and aircraft-handling trials near Hashirajima. Her secondary armament of twelve 127 mm guns, 12 triple 25 mm gun mounts, and four anti-aircraft machine guns was fitted 3–28 September 1942 at Kure, as well as a Type 21 radar. The ship was working up for the rest of the year. Arima was promoted to rear admiral on 1 November.
Musashi was assigned to the Combined Fleet, commanded by Admiral Isoroku Yamamoto, on 15 January 1943Whitley, p. 216 and sailed for Truk three days later, arriving on 22 January. On 11 February, she replaced her sister ship Yamato as the fleet's flagship. On 3 April, Yamamoto left Musashi and flew to Rabaul, New Britain to personally direct "Operation I-Go", a Japanese aerial offensive in the Solomon Islands. His orders were intercepted and deciphered by Magic, and American Lockheed P-38 Lightning fighters shot down his transport aircraft and killed him in Operation Vengeance while he was en route from New Britain to Ballale, Bougainville. On 23 April, his cremated remains were flown back to Truk and placed in his cabin on board Musashi.
On 17 May, in response to American attacks on Attu Island, Musashi—together with the aircraft carrier , two heavy cruisers, and nine destroyers—sortied to the northern Pacific. When no contact was made with American forces, the ships sailed to Kure on 23 May, where Yamamoto's ashes were taken from the vessel in preparation for a formal state funeral. Immediately afterwards, Musashis task force was significantly reinforced to counterattack American naval forces off Attu, but the island was captured before the force could intervene. On 9 June, Arima was relieved by Captain Keizō Komura. On 24 June, while being overhauled at Yokosuka Naval Arsenal, Musashi was visited by Emperor Hirohito and high-ranking naval officers. From 1 to 8 July, the ship was fitted with a pair of Type 22 radars at Kure. She sailed for Truk on 30 July and arrived there six days later, where she resumed her position as fleet flagship for Admiral Mineichi Koga.
In mid-October, in response to suspicions of planned American raids on Wake Island, Musashi led a large fleet—three carriers, six battleships, and 11 cruisers—to intercept American forces, but failed to make contact and returned to Truk on 26 October. She spent the remainder of 1943 in Truk Lagoon. Komura was promoted to rear admiral on 1 November and transferred to the 3rd Fleet on 7 December as chief of staff; Captain Bunji Asakura assumed command of Musashi.
The ship remained in Truk Lagoon until 10 February 1944, when she returned to Yokosuka. On 24 February, Musashi sailed for Palau, carrying one Imperial Japanese Army battalion and another of Special Naval Landing Forces and their equipment. After losing most of her deck cargo in a typhoon, she arrived at Palau on 29 February and remained there for the next month. On 29 March, Musashi departed Palau under cover of darkness to avoid an expected air raid, and encountered the submarine , which fired six torpedoes at the battleship; five of them missed, but the sixth blew a hole in diameter near the bow, flooding her with 3,000 tonnes of water.Stille, p. 42 The torpedo hit killed seven crewmen and wounded another eleven. After temporary repairs, Musashi sailed for Japan later that night and arrived at Kure Naval Arsenal on 3 April. From 10 to 22 April, she was repaired, while her anti-aircraft armament was substantially increased in the space freed up by removal of the beam-mounted triple turrets. When she undocked on 22 April, the ship's secondary battery comprised six 15.5 cm guns, twenty-four 12.7 cm guns, one hundred and thirty 25 mm guns, and four 13.2 mm machine guns. She also received new radars (which were still primitive compared to American equipment)Padfield, p. 285 and depth-charge rails on her fantail.