Japanese military service
In early May 1942, Taiyō Maru was requisitioned by the Imperial Japanese Army as an auxiliary transport. Her first and only assignment was to transport 34 soldiers and 1,010 civilians, including military governors, doctors, bureaucracy staff, educators and technicians needed to administer conquered Southeast Asian regions. The passengers included a large number of oil-field technicians bound for the Palembang, Sumatra and to revive oil refining facilities at Miri in Sarawak and Balikpapan, Borneo, as well as technicians for Malaya and for Java to install new equipment in the aluminum refinery facility and to construct a cement factory at Davao, Philippines. She was also loaded with 2,450 tons of war materiel including ammunition, hand grenades, and 150 tons of calcium carbide. She departed for Singapore on 7 May 1942 as part of a convoy consisting of Yoshino Maru, three cargo ships (Mikage Maru, Dover Maru, and Ryusei Maru) being escorted by auxiliary gunboat Peking Maru. Although Taiyo Maru was capable of more than 14 kn, she was limited to 8 kn by the speed of the slowest member of the convoy, and progress was further hampered by gale-force winds. On 8 May, the escorting auxiliary gunboat Peking Maru signaled sighting a submarine, and the crew went to battle stations. Around this time, most of the passengers were at their evening meal. At 19:45 hours, Taiyō Maru was struck portside stern by two torpedoes fired by USS Grenadier (SS-210). One torpedo hit the No. 2 hold, causing the calcium carbide stored there to catch fire and explode. Likewise, the cargo of ammunition and hand grenades exploded, blowing out the bottom of the vessel. The passengers rushed to the 18 lifeboats, only to find the deck on fire and most of the lifeboats destroyed by the explosions. By 20:20, the water reached C deck, and by 20:35, the ship started to submerge bow first. Captain Keisuke Harada and about a dozen crewmen decided to go down with the ship, which sank at 20:40 hours approximately 170 km southwest of Me-shima in the Danjo Islands.[6]
Peking Maru rescued 15 survivors, and the destroyer JAPANESE DESTROYER Minekaze and auxiliary gunboat Tomitsu Maru rescued 480 more survivors under gale-force conditions. A small fishing vessel rescued 48 more, for a total of 543 survivors. Captain Harada and 156 of his 263-man crew, 656 of 1,044 passengers and four of 53 armed guards/gunners died (total 817). The famous engineer Yoichi Hatta, who built Wushantou Dam and Chianan Irrigation, was a passenger of the ship when it sank. His body was found in Hagi, Yamaguchi, and after cremation, his ashes were returned to Taiwan.