was the second and last built for the Imperial Japanese Navy (IJN) during the 1910s. Although completed in 1918, she played no role in World War I. Hyūga supported Japanese forces in the early 1920s during the Siberian intervention in the Russian Civil War. In 1923, she assisted survivors of the Great Kantō earthquake. The ship was partially modernised in two stages in 1927–1928 and 1931–1932, during which her forward superstructure was rebuilt in the pagoda mast style. Hyūga was reconstructed in 1934–1936, improvements being made to her armour and propulsion machinery. Afterwards, she played a minor role in the Second Sino-Japanese War.
Despite the expensive reconstruction, the ship was considered obsolete by the eve of the Pacific War, and did not see significant action in the early years of the war. After the loss of most of the IJN's large aircraft carriers during the Battle of Midway in mid-1942, she was rebuilt with a flight deck replacing the rear pair of gun turrets to give her the ability to operate an air group of floatplanes; lack of aircraft and qualified pilots meant that Hyūga never operated her aircraft in combat. She participated in the Battle off Cape Engaño in late 1944, where she helped to decoy the American carrier fleet supporting the invasion of Leyte away from the landing beaches. Afterwards, the ship was transferred to Southeast Asia, occasionally serving as a flagship. In early 1945, Hyūga participated in Operation Kita, during which she transported petrol and other strategic materials back to Japan. The ship was then reduced to reserve until she was sunk during American airstrikes in July. After the war, Hyūga was scrapped in 1946–1947.
Design and description
The Ise class was designed as an improved version of the preceding . The ships had a length of overall, a beam of and a draught of at deep load.Lengerer March 2007, p. 9 They displaced at standard load and at deep load, roughly more than the earlier ships. Their crew consisted of 1,360 officers and ratings.
During the ships' modernisation in the 1930s, their forward superstructure was enlarged with multiple platforms added to their tripod masts to create a pagoda mast. Both ships were also given torpedo bulges to improve their underwater protection and to compensate for the weight of the extra armour. These changes increased their overall length to ,Chesneau, p. 171 their beam to and their draught to . Their displacement increased over to at deep load.Lengerer 2009, pp. 50–51 The crew now numbered 1,376 officers and enlisted men.
Propulsion The Ise-class ships had two sets of direct-drive steam turbines, each of which drove two propeller shafts, using steam provided by 24 Kampon Ro Gō water-tube boilers. The turbines were designed to produce a total of and give the ships a speed of . Hyūga reached from during her sea trials.Lengerer 2011, pp. 21–22 Each of the boilers consumed a mixture of coal and oil, and the ships carried enough of both to give them a range of at a speed of .Jentschura, Jung & Mickel, p. 26
During their 1930s modernisation, the boilers on each ship were replaced by eight new Kampon oil-fired boilers. The turbines were replaced by four geared Kampon turbines with a designed output of intended to increase their speed to . The fuel storage of the ships was increased which gave them a range of at , despite the additional weight.
Armament
The twelve Type 41 guns of the Ise class were mounted in three pairs of twin-gun, superfiring turrets that were numbered one through six from front to rear. The first pair was forward of the main superstructure, the second pair was amidships, and the last ones were aft of the rear superstructure.Lengerer 2011, pp. 24–26, 30 The ships' secondary armament consisted of twenty Type3 guns in single mounts. Eighteen of these were mounted in casemates in the forecastle and superstructure and the remaining pair were mounted on the deck above them and protected by gun shields.Lengerer 2011, pp. 33–34 Anti-aircraft defence was provided by four 40-calibre 3rd Year Type 8-centimetre (3 in) anti-aircraft (AA) guns in single mounts. The ships were also fitted with six submerged torpedo tubes, three on each broadside.Gardiner & Gray, p. 230
In 1931–1933 the AA guns were replaced with eight Type 89 dual-purpose guns, placed beside the forward superstructure in four twin-gun mounts.Lengerer March 2007, p. 12 Two twin-gun mounts for license-built Vickers two-pounder () light AA guns were also added while the pair of 14 cm guns on the upper deck were removed.Hackett & Kingsepp
During the mid-1930s reconstruction, the torpedo tubes were removed, and the Vickers two-pounders were replaced by twenty license-built Hotchkiss Type 96 light AA guns in 10 twin-gun mounts. This was the standard Japanese light AA gun during World War II, but it suffered from severe design shortcomings that rendered it a largely ineffective weapon. According to naval historian Mark Stille, the twin and triple mounts "lacked sufficient speed in train or elevation; the gun sights were unable to handle fast targets; the gun exhibited excessive vibration; the magazine was too small, and, finally, the gun produced excessive muzzle blast".Stille, p. 11 During the reconstruction, the forward pair of 14-centimetre guns in the forecastle were removed.
Protection The Ise-class ships' waterline protective belt had a maximum thickness of of Vickers cemented armour amidships; below it was a strake of armour. The upper armoured deck consisted of two layers of high-tensile steel totalling thick and the lower armoured deck also consisted of two layers of high-tensile steel, but only thick in total.Lengerer 2006, pp. 28–30; Lengerer 2011, p. 36 The turrets were protected with an armour thickness of on the face and 76 mm on the roof.Lengerer March 2007, p. 16 The casemate armour was thick and that of the barbettes was 299 mm thick rather than the originally planned 305 mm.Lengerer 2006, pp. 28–30
Construction and career
Hyūga, named after Hyūga Province, one of the traditional provinces of Japan, was laid down at the Mitsubishi Heavy Industries shipyard in Nagasaki on 6May 1915 and launched on 27 January 1917. Captain Shigeushi Nakagawa assumed command on 30 April and the ship was completed on that same day, too late for service in World War I.Silverstone, p. 330 Hyūga was then assigned to the 1st Battleship Division of the 1st Fleet. Captain Kinzaburo Mimura relieved Nakegawa on 10 November. An explosion in No.3 gun turret killed 11 crewmen and wounded another 25 during a gunnery exercise on 24 October 1919. Mimura was relieved in his turn by Captain Genjiro Katsuki on 20 November. Hyūga accidentally collided with and sank the schooner Hiromiya Maru, killing two of the sailing ship's crew, on 21 July 1920. On 29 August, the ship began the first of numerous patrols off the Siberian coast and in northern waters in support of Japan's Siberian Intervention against the Bolshevik Red Army. Captain Hidesaburo Ishikawa replaced Katsuki on 20 November and he was replaced by Captain Genji Ide on 20 November 1921.
The ship aided survivors of the 1923 Great Kantō earthquake in September 1923. From the early 1920s through the late 1930s, Hyūga often cruised off the coast of China. Little detailed information is available about her activities during the 1920s. The ship was overhauled in 1927–1928, during which her forward superstructure was enlarged and her aviation facilities improved. Beginning on 27 March 1932, she patrolled off the coast of China after the First Shanghai Incident, together with her sister ship and the battlecruisers and . On 14 June 1932, she was taking part in an exercise off Kyushu near the Mishima Islands in which a group of submarines practiced a mock combined attack on the 1st Battleship Division when the submarine unexpectedly surfaced in front of her. Hyūga, zigzagging at , took evasive action at the last minute and managed to avoid a direct collision with the stationary I-4, although Hyūga suffered minor damage to her hull plating when her bow grazed I-4′s hull.
Beginning on 24 October 1934, Hyūga was drydocked at Kure Naval Arsenal and underwent an extensive reconstruction and modernisation that lasted until 7September 1936. During the Second Sino-Japanese War, the ship ferried two battalions of the 3rd Sasebo Special Naval Landing Force to Port Arthur, China, on 19 August 1937. She began the first of her patrols off the southern Chinese coast on 15 September that lasted until early 1941. On 30 June 1940 Hyūga served as the flagship for the Emperor of Manchukuo, Henry Pu Yi, during his state visit to Japan. Together with Ise, the ship was transferred to the 2nd Battleship Division of the 1st Fleet on 15 November. Captain Noboru Ishizaki assumed command on 1September 1941.
Start of the Pacific War When full-scale war started for Japan on 8 December,Japan Standard Time is 19 hours ahead of Hawaiian Standard Time, so in Japan, the attack on Pearl Harbor happened on 8December. the division, reinforced by the battleships and and the light carrier , sortied from Hashirajima to the Bonin Islands as distant support for the 1st Air Fleet attacking Pearl Harbor, and returned six days later. Captain Chiaki Matsuda relieved Ishizaki on 20 February 1942. Together with the rest of the 2nd Battleship Division, Hyūga pursued but did not catch the American carrier force that had launched the Doolittle Raid on 18 April.
In May 1942 while conducting gunnery practice along with Nagato and Mutsu, the breech of Hyūgas left-hand gun in her No.5 turret exploded, killing 51 crewmen. The two aft magazines were rapidly flooded to save the ship and she returned to Kure for repairs. The turret was deemed not to be repairable and was removed. A circular plate of armour was welded over the barbette and three triple mounts for 2.5 cm AA guns were installed there. While under repair, the ship was fitted with one of the first experimental Type 22 surface-search radar sets in the IJN, but it was removed shortly afterwards.
Hyūga and the rest of the 2nd Battleship Division set sail on 28 May with the Aleutian Support Group at the same time most of the Imperial Fleet began an attack on Midway Island (Operation MI).Rohwer, pp. 168–169Parshall & Tully, p. 454 Commanded by Vice-Admiral Shirō Takasu, the division was composed of Japan's four oldest battleships, including Hyūga, accompanied by two light cruisers, 12 destroyers, and two oilers. Official records do not show the division as part of the larger Midway operation, known as Operation AL; they were to accompany the fleet under Admiral Isoroku Yamamoto, but were only to provide support to the Aleutian task force if needed.Parshall & Tully, p. 46
Conversion to a hybrid carrier