The Amagisan Maru was a large 450ft/136m, 7,620-ton Passenger Freighter built in 1933 by Mitsui Bussan Kaisha of Tokyo. She has six holds, and was designed with an extended bridge island amidships with holds served by kingposts built at the fore and aft ends of the island. Pairs of larger holds are located fore and aft of the midships island with tall topmasts mounted atop goal-post kingposts positioned between each pair. The Amagisan Maru sailed the Japan to New York route via the Panama Canal in the 1930’s, and was placed in the Japanese Naval Service in 1941. The word ‘Maru’ designates a merchant vessel.
On February 14th 1942 off the island of Davao, she narrowly survived a torpedo attack by the submarine USS Swordfish. On August 17th 1943 while alongside the fueling quay at Balikpapan she survived being strafed and bombed at masthead height by nine B-24’s. The attack reportedly sank four ships and damaged 2 more. However, only one bomb hit the bridge of the Amagisan Maru, killing her Commander and one enlisted man, and severely wounding several others. On October 8th 1943 off Rabaul she was attacked again, this time by a submarine and was hit in the No. 6 hold by a torpedo that caused flooding, but did not explode.
On February 17th 1944, the Amagisan Maru was in Truk Lagoon with a convoy unloading cargo when planes from the USS Bunker Hill were assigned targets at the anchorage between Fefan and Uman Islands. The Amagisan Maru, the largest ship present, was located at the southern end of the anchorage, where five Curtis Helldiver dive-bombers, and Four Grumman Avenger torpedo bombers attacked her. A 1,000 lb. bomb initially hit her, and then she was rocked by one or perhaps two torpedo hits forward and aft, ripping her and igniting her fuel oil. Within 15 minutes of the attack she was burning fiercely and sinking by the bow. She had gone under by the next strike.
She rests with a heavy list to port on a four-degree slope that gets progressively steeper towards the stern. The seabed depth at the bow is 140ft/42m and falls to over 200ft/60m at the stern. Her superstructure starts at 100ft/3om. Guns at both the bow and stern provide excellent photo opportunities, although the stern gun lies at 180ft/55m. A tanker truck rests off the port side, and hold No. 2 contains a car and other interesting cargo.