Shimushu Class, Japanese Patrol Boats

Photograph of Shimushu-class patrol boat

Wikipedia Commons


Tonnage 860 tons standard displacement
Dimensions 255' by 29'11" by 10'
77.7m by 9.1m by 3.0m
Maximum speed       19.7 knots
Complement 150
Armament 3 4.7"/45 dual-purpose guns
4 25mm AA guns
12 depth charges
2-shaft diesel (4200 bhp)
Range 8000 nautical miles (15,000 km) at 16 knots
Modifications 1942-5: Rebuilt with 24 depth charges and minesweeping gear removed.
1943-8: Armament increased to 15 25mm guns, 60 depth charges, one 3" A/S mortar. Fitted with Type 22 radar and Type 93 sonar.

The Shimushus were completed in 1940-41 in various naval yards. Originally intended for fishery protection in the Kuriles, they were finally authorized as coast defense ships (Kaibōkan), designed for patrol, minesweeping, and escort duties, and were suitable for mass production. They were built strongly for service in the stormy North Pacific and could have been the backbone of a decent escort force, had the Japanese been that foresighted. However, their original displacement of 1200 tons was reduced so that the funds could be clandestinely shifted to construction of the Yamatos, and the subsequent and more numerous Etorofu class was not ready before war broke out in the Pacific.

Units in the Pacific:


Cam Ranh      

Hachijo Ominato Crippled 1945-5-11 at Kataoka Bay and not repaired



Torpedoed 1944-5-31 off Matsuwa by Herring


Hittokapu Bay     


Evans and Peattie (1997)

Jentschura, Jung, and Mickel (1977)

Materials of IJN (accessed 2009-11-9)

Worth (2001)

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