Seisho Maru Seisho Maru ( , " Seishō Maru " ) was a cargo ship for Mitsui Bussan Kaisho in military service that was sunk by an American submarine during World War II . The ship had been built as SS " West Caruth , a cargo ship for the shortly after the end of World War I . Shortly after completion , the ship was inspected by the United States Navy for possible use as USS " West Caruth " ( ID - 2850 ) but was neither taken into the Navy nor ever commissioned under that name . Before being sold to Japanese owners in 1928 , she was also known as SS " Exmoor and SS " Antonio Tripcovich " . " West Caruth " was built in 1918 for the , as a part of the " West " boats , a series of steel - hulled cargo ships built on the West Coast of the United States for the World War I war effort , and was the second ship built at Southwestern Shipbuilding in San Pedro , California . After operating for four years under American registry , she was sold several times and operated under British , Italian , and Japanese registry throughout the remainder of her career . In November 1944 , while serving as Japanese transport " Seisho Maru " during World War II , she was sunk by U . S . Navy submarine . Design and construction . The " West " ships were cargo ship s of similar size and design built by several shipyards on the West Coast of the United States for the for emergency use during World War I . All were given names that began with the word " West " , like " West Caruth " , the second of some 18 " West " ships built by the Southwestern Shipbuilding of San Pedro , California . " West Caruth " ( Southwestern Shipbuilding No . 2 ) was launched at 08 : 00 on 31 December 1918 by sponsor Betty Howard , the nine - year - old daughter of company vice president , William F . Howard , and completed in February 1919 . " West Caruth " was , and was long ( between perpendiculars ) and abeam . The ship had a single triple - expansion steam engine that drove a single screw propeller , and moved the ship at up to . Career . " West Caruth " was inspected by the 12th Naval District of the United States Navy after completion for possible use as a service collier and was assigned the identification number of 3850 . Had she been commissioned , she would have been known as USS " West Caruth " ( ID - 3850 ) , but the Navy neither took over the ship nor commissioned her . The cargo ship sailed for the under American registry for the first four years of her existence , and sailed to the East African ports of Dakar and Monrovia through 1921 . The " Los Angeles Times " reported that " West Caruth " sailed out of Los Angeles in both transpacific and European – Pacific service for two years . In 1923 , " West Caruth " was sold to the North Devon Steamship Company and operated as tramp steamer " Exmoor " under the British flag . In 1924 , she was purchased by the Tripcovich Shipping Company of Trieste and sailed under the Italian flag as " Antonio Tripcovich " . Four years later , she was renamed " Seisho Maru " as a part of Oguma Shoten Gomei Kaisha of Tsurumi under Japanese registry . By the early 1930s " Seisho Maru " had been sold to Mitsui Bussan Kaisho . There is scant record of the ship ' s movements under any of her later names . The " Los Angeles Times " reports her arrival at West Coast ports as " Seisho Maru " at least twice . In March 1930 , the ship arrived at Tacoma , Washington , from Singapore to pick up a load of logs for export . Another notice in November 1933 noted her impending return to Los Angeles , where she was scheduled to take on a load of borax and scrap brass . In early May 1939 , " Seisho Maru " ran aground in Tokyo Bay , but was refloated after several days . During World War II , " Seisho Maru " served as an army transport , but sources reporting her movements are incomplete . It is known that she was one of some 20 ships that departed Takau as part of three combined convoys — TASA - 17 , TE - 03 , and No . 82 — in mid - April 1944 . " Seisho Maru " and seven other ships formed convoy MI - 27 which departed Moji for Miri , Borneo , on 15 November that same year . Escorted by a converted minesweeper and three smaller vessels , the convoy hugged the coast of the Korean peninsula to try to avoid American submarines . Nevertheless , a group of three submarines — , , and — found and attacked the convoy on the night of 17 / 18 November . Torpedoes from " Sunfish " sank " Edogawa Maru " and damaged " Seisho Maru " shortly after 22 : 00 , while " Peto " sank " Osakasan Maru " at 23 : 40 . At 01 : 30 , the damaged " Seisho Maru " engaged in a gun battle with a surfaced submarine . Then , at 03 : 17 , another spread of torpedoes from " Sunfish " finished off " Seisho Maru " , which sank at position in the East China Sea .