TheShōkai Maru-class high-powered tugboat (照海丸型強力曳船,,Shōkai Maru-gata kyōryoku eisen) was a class ofgunboat of theImperial Japanese Army, serving duringWorld War II. The IJA official designation was high-poweredtugboat, however, they did not have any towing facilities. They were actually gunboat and escort ships. Many records were lost after theSurrender of Japan.

• 20 April 1938; completed atŌsaka Iron Works, Sakurajima Factory.
• Hereafter, her record was not left to documents.

• 27 February 1939; completed at Ōsaka Iron Works, Sakurajima Factory.
• 20 to 26 October 1944; escort operation for Harukaze Convoy (Manila -Kaohsiung).^[5]
• 22 to 27 November 1944; escort operation for TaKa-206 Convoy (Keelung -Naha).^[6]
• Survived war inKushigahama; later rebuilt as short-range passenger atMitsubishi Heavy Industries, Hiroshima shipyard.^[3]
• 1 May 1946; transferred toJapanese National Railways (later converted to training ship).^[3]
• 1 September 1948; transferred toJapan Maritime Safety Agency as patrol boat (PB-31, later PS-31).^[7]
• 23 June 1951; retired.^[7]

• Monthly Ships of the World,"Kaijinsha"., (Japan)
  • No. 506, February 1996
  • No. 613, Special issue "All ships of Japan Coast Guard 1948–2003", July 2003
• Shinshichirō Komamiya,The Wartime Convoy Histories,"Shuppan Kyōdōsha". Archived fromthe original on 2011-07-22. Retrieved2011-12-15. (Japan), October 1987
• Tatsuo Furukawa,Wake of train ferry 100-year (2nd issue),"Seizando-Shoten". Archived fromthe original on 2009-04-17. (Japan), June 2001,ISBN 4-425-92141-0
• 100 year History of Hitachi Zōsen,Hitachi Zōsen Corporation, March 1985
• Policy and Legal Affairs Division-Japan Maritime Safety Agency (JMSA),30 year History of Japan Maritime Safety Agency, Japan Maritime Safety Agency, May 1979

• World War II naval ships of Japan
• Ships of the Imperial Japanese Army
• Gunboats
• Patrol vessels of the Japan Coast Guard
• Ships built by Osaka Iron Works

• Ship infoboxes without an image
• Articles containing Japanese-language text