Japanese aircraft carrier Kaiyo Description . The ship was ordered as the fast luxury passenger liner " Argentina Maru " by " Osaka Shosen Kaisha " ( OSK ) in 1938 . In exchange for a subsidy of her building costs by the Navy Ministry , she was designed to be converted to an aircraft carrier . " Argentina Maru " was completed in 1939 and rated at . After being rebuilt , the ship had a length of overall . She had a beam of and a draft of . She displaced at standard load . As part of her conversion , her original diesel engines , which had given her a top speed of , were replaced by a pair of destroyer - type geared steam turbine sets with a total of , each driving one propeller . Steam was provided by four water - tube boilers and " Kaiyo " now had a maximum speed of . She carried enough fuel oil to give her a radius of . Her crew numbered 829 officers and men . The ship ' s flight deck was wide and " Kaiyo " had a single hangar , served by two aircraft elevator s , mounted on the centerline . She was not built with an island and could operate 24 aircraft . The ship ' s primary armament consisted of eight 40 - caliber 12 . 7 cm Type 89 anti - aircraft ( AA ) guns in twin mounts on sponsons along the sides of the hull . They fired projectiles at a rate between 8 and 14 rounds per minute at a muzzle velocity of ; at 45° , this provided a maximum range of , and a maximum ceiling of . " Kaiyo " was also initially equipped with eight triple 25 mm Type 96 light AA guns , also in sponsons along the sides of the hull . They fired projectiles at a muzzle velocity of ; at 50° , this provided a maximum range of , and an effective ceiling of . The maximum effective rate of fire was only between 110 and 120 rounds per minute due to the frequent need to change the fifteen - round magazines . In early July 1944 , 20 single 25 mm guns were added as were eight depth charge s . Some sources say that a number of 28 - round AA rocket launchers were added in late 1944 . Each rocket weighed and had a maximum velocity of . Their maximum range was . Early warning was provided by a Type 2 , Mark 2 , Model 1 air search radar that was installed on the side of the flight deck in November 1943 . Service history . " Argentina Maru " was initially used for troop transport after the beginning of the Pacific War in December 1941 . The ship began conversion at Nagasaki on 10 December 1942 , the day after she was purchased . After the conversion was completed on 23 November 1943 , she was renamed " Kaiyo " . Her initial duties were to transport aircraft to Japanese overseas bases . Her first such task to ferry aircraft for the 23rd Air Flotilla to Singapore via Manila in January 1944 as part of Convoy HI - 33 . On her return journey , the ship transported aircraft of the 551st Air Group to Truk . On 10 February , en route to Truk from Palau , the submarine made a night attack on " Kaiyo " , but the torpedo es missed . " Kaiyo " was briefly refitted between 23 February and 2 March and was assigned to the 1st Surface Escort Division on 17 March . She escorted Convoy HI - 57 to Singapore via Taiwan and Indochina in April . She escorted Convoy HI - 58 on the return voyage ; one of her aircraft spotted the submarine on the surface behind the convoy . The submarine was damaged by the escorts , but escaped . In late May , " Kaiyo " formed part of the escort for Convoy HI - 65 , together with the escort carrier , bound for Singapore . One of the escorts was torpedoed en route and two of the merchantmen collided while trying to dodge the other torpedoes . The rest of the convoy arrived at Singapore on 12 June . " Kaiyo " was assigned to fast Convoy HI - 66 for the return voyage and reached Japan on 26 June . She was briefly docked at Kure Naval Arsenal in early July to have more 25 mm AA guns fitted . Together with the escort carrier , " Kaiyo " was loaded with aircraft bound for the Philippines to be delivered in Convoy HI - 69 . They departed on 13 July and arrived a week later . The convoy left Manila four days later and reached Japan on 1 August . The ship ' s machinery broke down as she was preparing to join another convoy on 4 August and she was transferred to Sasebo . On 25 October , " Kaiyo " ferried a dozen transport aircraft to Keelung , Taiwan , and arrived at Kure on 2 November . The ship was assigned to escort Convoy HI - 83 to Singapore via Taiwan and Hainan Island on 25 November and arrived on 13 December . En route , she was assigned to the First Escort Fleet on 10 December . While returning to Japan with Convoy HI - 84 later that month , " Kaiyo " was attacked and missed by the submarine on 31 December . After arriving at Moji on 13 January 1945 , the ship was transferred to Kure and assigned to pilot training in the Inland Sea . On 19 March 1945 , while moored at Kure , " Kaiyo " was attacked by an American carrier aircraft from Task Force 58 . She was hit in the port engine room by a bomb that started fires and caused some flooding . The ship started to list and was moved into shallow water near Etajima Island lest she sink . On 20 April she was assigned to serve as a target ship for kamikaze crews . " Kaiyo " resumed her pilot training duties a month later and hit a mine on 18 July with only minor damage . Six days later , she struck a mine while attempting to dodge attacks by British - flown Grumman TBF Avenger torpedo bombers . She was hit twice more , possibly by rockets , and was flooding badly . The ship was towed overnight to Beppu Bay and deliberately grounded the following morning to prevent her from sinking . The ship was attacked again on 28 July by American carrier aircraft that knocked out the ship ' s power and stopped her pumps . " Kaiyo " was also hit by 18 rockets and a total of 20 crewmen were killed by the attacks . The damage caused her to ground again with a list to port . The next day she was attacked again by B - 25J Mitchell medium bomber s of the Fifth Air Force as well as by aircraft from the carrier . The amount of damage inflicted by these attacks , if any , is unknown , but they did cause the ship ' s captain to abandon attempts to repair the ship . He ordered that the boilers be flooded with sea water and the machinery coated in oil to better preserve it . Some crewmen were left aboard to man the AA guns . Low - level air strikes by Okinawa - based B - 25J Mitchells of the United States Army Air Forces 38th Bomb Group on 9 August further damaged the carrier , despite extensive use of camouflage netting and foliage . The following day , the ship ' s list increased and she was ordered abandoned . " Kaiyo " was struck from the Navy List on 20 November and scrapped in place from 1 September 1946 and 30 January 1948 by Nissan Salvage .