The Sankisan Maru
Passenger cargo ship sitting upright. Much to see – bow gun, trucks, tanks, mines, shells, bombs, aircraft engines, ammunition, china and depth charges on stern.
Depth: 3-90ft/1-27m (stern part at 160ft/48m)
The Sankisan Maru is a 370ft/112m, 4,776-ton Japanese Army Cargo Ship. Both the background history and the circumstances under which it was sunk are somewhat of a mystery. Although it is said that she was originally called the Red Hook, was an American vessel doing Northwest trade during the depression, and was captured by the Japanese in 1942, recent archival research now points to the ship sunk at Truk as being a different vessel with the same name. Information supplied from various Japanese sources indicate that the ship was built for the Nippo Yusen Kaisha company to transport civilian cargo until it was requisitioned by the Japanese Army to transport military personnel and supplies. The word ‘Maru’ designates a merchant vessel.
According to these Japanese sources, the Sankisan Maru was heavily involved in the Indo-China-Empire rice trade, particularly ‘Thai’ rice from Bangkok, ‘Saigon Rice’, and rice from Korea. She was capable of carrying 6,000 tons of rice during her various runs. In all likelihood, the heavy attrition of Japanese ships during the war necessitated a change from rice transportation to moving munitions for the Japanese Army. She was in the Saipan area in November of 1943 and Yokosuka in January of 1944 prior to her arrival in Truk on February 12th 1944.
Anchored off the western shore of Uman Island, the Sankisan Maru was heavily laden with a cargo of war supplies and ordinance when American planes attacked it during Operation Hailstorm. On February 17th 1944, four SB2Cs from the USS Bunker Hill attacked the Sankisan Maru after attacking the Amagisan Maru, hitting the Sankisan Maru with a 1,000 lb. bomb. On February 18th 1944 planes from the USS Bunker Hill returned and the Sankisan Maru was hit by a torpedo in the aft holds which blew the vessel apart, decimating the entire midship superstructure, and flinging the stern section into deeper water. There is also the possibility that fires started by the initial bomb ultimately caused the munitions in the hull to ignite, thereby causing the massive explosion.
She rests upright on an even keel with the deck at 50ft/15m and the sea bottom at 90ft/27m. Six trucks, rifle and machine gun ammunition, detonators, aircraft parts (including a wing, wheels, radial engines and cowlings) and other cargo are located in various holds with excellent soft coral on the masts and other parts of the structure. The small remaining stern section that remains sits at 160ft/48m approx 200ft/60m away from the rest of the ship. Due to these beautiful soft corals and the wide variety of fish species seen at the Sankisan Maru, it has become a favorite for many divers.