Shōkai Maru-class tugboat

Class overview
Name	Shōkai Maru class
Builders	Ōsaka Iron Works, Sakurajima Factory
Operators	Imperial Japanese Army Japanese National Railways Japan Maritime Safety Agency
Preceded by	Wajima Maru class
Succeeded by	Hokkai Maru class
Built	?–1939
In commission	1938–1951
Planned	2
Completed	2
Lost	?
Retired	1 (?)
General characteristics
Type	High-powered tugboat (gunboat)
Displacement	175 long tons (178 t) gross [1]
Length	41.2 m (135 ft 2 in) o/a [2][3]
Beam	6.0 m (19 ft 8 in) [2][3]
Draft	2.8 m (9 ft 2 in) [2]
Propulsion	2 × diesels, 700 bhp [1][3]
Speed	14 knots (16 mph; 26 km/h) [1][3]
Armament	unknown [4]

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

Ships in class

Shōkai Maru (照海丸)

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

Eikai Maru (映海丸)

• 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 in Kushigahama; later rebuilt as short-range passenger at Mitsubishi Heavy Industries, Hiroshima shipyard.^[3]
• 1 May 1946; transferred to Japanese National Railways (later converted to training ship).^[3]
• 1 September 1948; transferred to Japan Maritime Safety Agency as patrol boat (PB-31, later PS-31).^[7]
• 23 June 1951; retired.^[7]

Footnotes

1. Monthly Ships of the World (1996), p. 33
2. JMSA (1979), p. 299
3. Tatsuo Furukawa (2001), p. 142
4. 1 × tank gun turret (forecastle deck) and 1 × LMG (top of bridge) were confirmed by Shōkai Maru photograph, other armaments were unknown.
5. Shinshichirō Komamiya (1987), p. 279
6. Shinshichirō Komamiya (1987), p. 297
7. Monthly Ships of the World (2003), p. 44

Bibliography

• 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 from the original on 2011-07-22. Retrieved 2011-12-15. (Japan), October 1987
• Tatsuo Furukawa, Wake of train ferry 100-year (2nd issue), "Seizando-Shoten". Archived from the 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