The Imperial Japanese Navy was not completely satisfied with its first effort at super-dreadnoughts, the Fuso class. Japanese naval architects slightly modified the design to include more protection and a higher speed, resulting in the battleships Hyuga and Ise. Completed in September 1918, Hyuga carried 12 14″ guns in six twin turrets, displaced about 33000 tons, and could make 23.5 knots. The IJN preferred the six twin mounts to the four triple mounts typical to American ships because the former allowed a longer, narrower hull and thus a higher speed. Unfortunately, it also resulted in less extensive protection (armor spread across a larger area) and in an inefficient distribution of magazines and machinery. Nevertheless, Hyuga was an effective ship, carrying a heavier armament than Queen Elizabeth and faster than her American counterparts. Like most Japanese battleships, Hyuga led an uneventful interwar career, with the exception of a reconstruction between 1934 and 1937 that improved her protection and increased her speed to 25 knots.
In spite of her relatively high speed for an old battleship, Hyuga was not employed during the initial Japanese offensive of 1941 and 1942. Hyuga’s first action came in April 1942. An American carrier task force, led by Admiral William “Bull” Halsey and including the USS Enterprise and the USS Hornet, launched 16 B-25 medium bombers in an operation intended to bring the war to the Japanese home islands. Hyuga, Ise, Fuso, and Yamashiro were detailed to intercept the American task force, but found only a Russian freighter travelling from San Francisco to Vladivostok. Disappointed, the Japanese ships returned to port. A month later Hyuga suffered an explosion during gunnery practice that killed 51 sailors and nearly resulted in the loss of the ship. Hyuga’s #5 turret, now inoperable, was removed and replaced with anti-aircraft guns. In June, again in concert with her sister Ise, Hyuga participated in the invasion of the Aleutian Islands. Unfortunately for the IJN, the concurrent operation to invade Midway Island resulted in disaster and the loss of four aircraft carriers.
The devastating losses at Midway left the IJN searching for ideas to increase carrier deck space. The first plans envisioned a full conversion of the older battleships, leaving no main armament and a deck capable of operating 54 conventional aircraft. The IJN decided that this would take too long, and instead opted for a half-measure in which the aft two turrets of Hyuga and Ise would be removed and replaced with a flight deck, hangar, and catapults. While Hyuga and Ise could not equal a fleet or even a light carrier, and were not expected to carry the most modern aircraft, it was hoped that they would ease the load of the surviving carriers, especially in regards to recon aircraft. Because the flight deck was short, the 22 aircraft that Hyuga could launch would need to land on either a normal carrier or a land base. The Japanese also converted the incomplete Yamato class battleship Shinano into an aircraft carrier support vessel, designed to carry only about 50 aircraft but with enough space for fuel, ammunition, and machine shops to support a full carrier task force. Hyuga began her conversion in late 1942 and completed in in late 1943. Heavy concrete was added to the flight deck in order to compensate for the loss of weight and to increase structural stability.
Although Hyuga launched aircraft in various tests, in practice there were simply not enough trained pilots to fill the deck space of the existing Japanese carriers. Thus, the flight deck was not used as intended during operations. Instead, rockets and additional anti-aircraft weapons were installed. In October 1944, Hyuga, her sister Ise, and four remaining Japanese carriers were deployed, under the command of Admiral Ozawa, as a decoy force intended to draw Halsey’s Third Fleet away from Leyte Island and allow Admiral Kurita’s surface force to destroy the American transports. The first part of this operation was more or less successful, as American aircraft attacked Ozawa’s force, destroying the four carriers and lightly damaging Hyuga. Hyuga retired, avoiding attacks from at least four different USN submarines along the way.
Following Leyte Gulf, Hyuga was deployed to Southeast Asia. In February 1945, narrowly avoiding multiple air and submarine attacks, she and her sister Ise returned to Japan. No fuel and no ammunition meant that Hyuga would not play an active role in the rest of the war. On July 24, 1945 American aircraft attacked Hyuga and sank her in shallow water. She was scrapped over the course of the next two years.
Trivia: What was the first battleship to be armed with guided missiles?