Japanese aircraft carrier Un'yō

Un'yō (雲鷹) was a Taiyō-class escort carrier operated by the Imperial Japanese Navy in World War II. It was originally constructed as the passenger vessel Yawata Maru (八幡丸).

Civilian Use


The Yawata Maru was a Japanese ocean liner owned by Nippon Yusen Kaisha. The ship was built in 1938-1940 by Mitsubishi Shipbuilding & Engineering Co. at Nagasaki, Japan. It was laid down in December 1938, launched in October 31, 1939 and left port on July 31, 1940 on her maiden voyage. The vessel's pre-war design anticipated passenger service; but when work was completed, the onset of war had created somewhat different priorities.

The vessel was created as a sister ship of the Kasuga Maru, and the Nitta Maru. None of the three survived the Second World War. Each in succession was re-fitted as a troopship; and each was later converted to an aircraft carrier. In 1941, Kasuga Maru was re-commissioned as the Japanese aircraft carrier Taiyō and in late 1942, the Nitta Maru was recommissioned as the Japanese aircraft carrier Chūyō.

When first launched, this ship was named after an important Shinto shrine.

The 17,163-ton vessel had a length of 559.3 feet (170 m), and her beam was 74 feet (22.5 m). The ship had an average speed of 18.5 kn.

Military Use
The ship was requisitioned by the Imperial Japanese Navy in October 1941. Initially, the ship was assigned for transporting prisoners of war. Between 25 November 1941 and 31 May 1942, Yawata Maru was rebuilt in Kure to be an auxiliary aircraft carrier. Her flight deck measured 150 x and was equipped with two elevators. She had no island, catapults or arresting gear. On 31 July 1942, she was reclassified as an escort carrier and renamed Un'yō.

Un'yō was used primarily for flight training and aircraft transport. She often sailed with her sister ships JAPANESE AIRCRAFT CARRIER Taiyō and JAPANESE AIRCRAFT CARRIER Chūyō.

On 10 July 1943, off Truk, she was hit by a single torpedo fired by the American submarine USS Halibut (SS-232).

On 19 January 1944, while en route to Yokosuka, she was hit and heavily damaged by three torpedoes fired by USS Haddock (SS-231). While sheltering at Garapan Anchorage, Saipan on 23 January, a follow-up attack by Halibut was driven off. Following repairs, she was back in service by June 1944.

On 17 September, Un'yō was struck by two torpedoes fired by USS Barb (SS-220). Her crew’s struggle to keep Un'yō afloat was in vain. Of the approximately 1,000 people aboard (crew and passengers), 761 were rescued. Its last position was 220 nmi southeast of Hong Kong, 19.13333°N, 116.6°W.