Aikoku Maru ( 1940 ) Background . " Aikoku Maru " was laid down at the Mitsui Tamano shipyards in Okayama Prefecture on 29 December 1938 . She was designed to be a combined passenger liner / cargo vessel for the Osaka Shosen Lines ’ s regularly scheduled services to South America . Provisionally named " Kyoto " , the design for the new vessel was to have boasted of luxurious suite rooms . The vessel was built with large government subsidies provided from 1936 to encourage the production of large , high - speed transports and tankers , which could be quickly converted to military use in times of conflict . The vessel was launched on 25 April 1940 , and was named " Aikoku Maru " at that time . Design . Although ostensibly a luxury ocean liner , the military had a say in the design of " Aikoku Maru " with an eye towards its future use as a troop transport . Provision was made for landing craft and for the anchoring of naval artillery . Overall , the vessel was in displacement , with a length of . Powered by two Mitsui B & W diesel engines with driving twin screws , she was capable of . Operational history . Immediately on completion on 31 August 1941 , " Aikoku Maru " was officially requisitioned by the Imperial Japanese Navy . She was converted into an armed merchant cruiser from 5 September while still at Tamano , with the installation of four 15 cm / 50 41st Year Type guns , two QF 12 pounder 12 cwt naval gun s , two Type 93 13 . 2 - mm machine gun s and two quad - mount 533 - mm torpedo tubes . She was also fitted with powerful searchlights and boom for handling a Kawanishi E7K float plane ( with one additional aircraft as a spare ) . As an auxiliary cruiser and submarine tender . On 15 October 1941 , the 24th Raider Squadron ( CruDiv24 ) , consisting of the " Aikoku Maru " , " Hōkoku Maru , " and " Kiyosumi Maru " was created under the Combined Fleet . " Aikoku Maru " and her sister ship " Hōkoku Maru " were forward deployed to Jaluit Atoll in the Marshall Islands at the end of November in preparation for the upcoming hostilities against the United States . On 13 December 1941 , " Aikoku Maru " and " Hōkoku Maru " sank the SS " Vincent " ( 6210 GWT ) , an American merchant vessel with a cargo of rice from Australia to Panama at 22 - 41S , 118 - 19E . On December , the reconnaissance floatplane from " Aikoku Maru " spotted the American freighter SS " Malama " ( 3275 GWT ) en route to Manila . The plane failed to return , and despite searching by both Japanese vessels , no trace was ever found of the missing aircraft . The second floatplane reacquired SS " Malama " south of the Cook Islands on 2 January 1942 , and after making a strafing attack , orders the ship to stop . After the crew of the SS " Malama " abandoned ship , she was sunk at 26 - 39S , 151 - 24W . Aside from the missing pilot , there were no casualties on either side , and the sortie was concluded on 20 January . Crudiv24 returned to Hashirajima in February , after disembarking their 76 POWs at Oita . On 14 February 1942 , at Kure Naval Arsenal , " Aikoku Maru " ’ s four 152 - mm guns were replaced by eight 14 cm / 50 3rd Year Type naval gun s . She was also modified to carry submarine torpedoes in her hold to enable her to function as an auxiliary submarine tender . In this capacity , " Aikoku Maru " and " Hōkoku Maru " were deployed with the IJN 6th Fleet on 10 March to support submarine operations off the east coast of Africa and Mozambique . At the end of March , " Aikoku Maru " and " Hōkoku Maru " returned to Kure , where CruDiv24 was formally disbanded , and they are reassigned to Subron8 , operating out of Penang from early April , supporting submarine operations in the western Indian Ocean . On 9 May , " Aikoku Maru " captured the Dutch tanker " Genota " ( 7 , 897 GWT ) 480 miles SSE of Diego Suarez , Madagascar . On 5 June , she sank MV " Elysia " ( 6757 GWT ) , a British freighter carrying a number of Allied troops at 27 - 19S , 37 - 01E . On 12 July , she captured the New Zealand registered freighter Hauraki near Ceylon . She placed a prize crew on board , but en route back to Japan , her New Zealander engine crew managed to sabotage the cargo and engine spares . After repairs at Seletar Naval Base in Singapore , the floatplanes on " Aikoku Maru " were upgraded to two Aichi E13A s , two dual Type 96 25 mm AT / AA Gun s were added , and an additional 70 torpedoes were loaded . She continued to be based out of Penang until late August under the command of Tamotsu Oishi . From September , " Aikoku Maru " was assigned to the IJN 8th Fleet and tasked with transporting the IJA 38th Infantry Division to Rabaul for the reinforcement of Guadalcanal . After accomplishing this mission by 10 October , her Commerce Raiding Unit was reactivated , and Aikoku Maru transited the Sunda Strait into the Indian Ocean on 7 November , together with " Hōkoku Maru " . On 11 November , the raiders attacked the Dutch tanker " Ondina " ( 6341 GWT ) , which was accompanied by the minesweeper southwest of the Cocos Islands . " Hōkoku Maru " was closer and attacked first , but a shot from " Ondina " ’ s 4 - in guns hit " Hōkoku Maru " ’ s starboard torpedo tube , and detonated the torpedo . A fire broke out , which quickly raged out of control , causing the aft magazine to explode , sinking the vessel . " Aikoku Maru " then arrived , and drove off " Bengal " while " Ondina " also attempted to escape . " Aikoku Maru " scored six hits on " Ondina " with her guns , but her two torpedoes missed . However , with their ship damaged and out of ammunition , the crew of " Ondina " abandoned ship . " Aikoku Maru " rescued 278 survivors of the " Hōkoku Maru " , and returned to Penang , and from there to Singapore and Rabaul . Meanwhile , the crew of the " Ondina " managed to re - enter their ship and effect repairs , escaping to Fremantle , Australia . As a military transport . From 16 December 1942 , " Aikoku Maru " was reassigned back to the IJN 8th Fleet , primarily as a military transport to support New Guinea operations , and her aircraft were disembarked . While unloading cargo at Madang on 18 December , she was attacked in an air raid by B - 17 Flying Fortress bombers of the 43rd Bomb Group of the USAAF Fifth Air Force , but was not hit . She returned to Kure on 29 December 1942 . As part of “ Operation C ” ( the Reinforcement of New Guinea ) , on 5 January 1943 , " Aikoku Maru " loaded the IJAAF 209th Airfield Battalion , 14th Aerial Repair Shop and others , a total of 691 men plus 34 vehicles at Pusan in Korea , arriving at Rabaul on 14 January . She was then sent to Tsingtao in Japanese - occupied China , arriving 24 January , and from there to Cebu ( 2 February ) and Palau ( 7 February ) , where she loaded additional troops and cargo , delivering the reinforcements successfully to Wewak on 23 February . She returned to Kure on 5 April . On 10 July 1943 , as part of a convoy including the aircraft carrier , " Aokoku Maru " was attacked by 170 nm north of Truk , which fired six torpedoes . One struck " Aikoku Maru " , causing moderate damage . On her return voyage , on 15 July , she was attacked again , this time by , whose four torpedoes all missed . She returned to Kure on 2 September . On 6 October , " Aikoku Maru " returned to Tamano for repairs and refitting with additional weaponry , which included two 152 - mm guns and four twin - mount Type 96s . The refitting work was completed by 31 December 1943 . On 21 January 1944 , " Aikoku Maru " loaded the 629 men of the 66th Naval Guard Unit , with ammunition , supplies and construction materials . The convoy was attacked 300 nm NW of Truk by , which sank the minelayer and transport " Yasukuni Maru " ; however , " Aikoku Maru " was undamaged and reached Truk on 1 February . After making an abortive run to Brown Island , she returned to Truk on 16 February to find that most of the capital ships had evacuated the base in anticipation of an impending American attack . " Aikoku Maru " began loading ammunition and making preparations for departure to Rabaul , loading troops of the 1st Amphibious Brigade . However , before preparations were complete , Operation Hailstone began , with the US Navy Task Force 58 striking at Truk with 30 air strikes of over 150 aircraft each every hour for a period of two days . On the first day , 17 February1944 , Aikoku Maru was bombed by aircraft from the , with the first bomb exploding in the officer ’ s wardroom , causing a fire . She was hit three more times in this attack , and was hit again in the second attack by a torpedo which set off the ammunition in her No . 1 hold , shearing off the bow . " Aikoku Maru " sank in two minutes at , with most of the 945 crew and passengers . " Aikoku Maru " was removed from the navy list on 30 March 1944 . Shipwreck . The wreck of " Aikoku Maru " is a popular scuba diving spot in the waters of Truk Lagoon , despite her depth of approximately . The wreck is upright , with the bridge at the meter level and deck extending approximately 10 meters deeper . The remains of an anti - aircraft gun on top of the aft deckhouse is often photographed , as are the scattered dishes and kitchen utensils in her galley . Her wreck was first dived by the famous French explorer Jacques - Yves Cousteau in 1969 , but she was not positively identified until later . In July 1980 , a Japanese recovery team retrieved the remains of approximately 400 men who were killed in the attack , and placed a memorial monument on her deck , but the remains of hundreds more remain on site .