The were a class of patrol boats of the Imperial Japanese Navy (IJN), serving during World War II. 9 vessels were converted from s and 1 vessel was converted from a in 1940.

Background

In 1939, the IJN was liberated from

London Naval Treaty The London Naval Treaty, officially the Treaty for the Limitation and Reduction of Naval Armament, was an agreement between the United Kingdom, Japan, France, Italy, and the United States that was signed on 22 April 1930. Seeking to address is ...

, and they built many s. On the other hand, aging of the ''Momi''-class destroyers was serious. Their boilers were degraded due to the operating conditions present in destroyers. Some ''Momi''-class destroyers were not able to show 30 knots speed. The Navy General Staff made the ''Confidential Document No. 456''. It was an order to rebuild them into patrol boats - about four s and six ''Momi''-class destroyers. The IJN chose nine ''Momi'' class and one ''Wakatake'' class. Three ''Momi''s and one ''Wakatake'' were increased, because two ''Minekaze''s were decreased.

Rebuilding

* Ten vessels were sent to dockyards for rebuilding. "Q" turret, all of torpedo tubes and one boiler were removed in 1940. * In the second half of 1941, the IJN rebuilt them once again for war preparations.About the time of their entering a dock, correct historical materials were not left. They were rebuilt to the landing craft carrier. The Y turret was moved to a place of the "Q" turret. Furthermore, a slope for was installed to their stern, and added deck house for one company of Navy Landing Force. As for the ''No. 31'' and the ''No. 46'', those rebuilt were not done.

Service

* 10 and 23 December 1941: Sortie for the Battle of Wake Island. (''No. 32'' and ''No. 33'') * 12 December 1941: Sortie for the invasion of Legazpi. (''No. 34'', ''No. 35'' and ''No. 36'') * 20 December 1941: Sortie for invasion of Davao. (''No. 36'' and ''No. 37'') * 25 December 1941: Sortie for invasion of Jolo. (''No. 36'' and ''No. 37'') * 11 January 1942: Sortie for the Battle of Tarakan. (''No. 36'', ''No. 37'' and ''No. 38'') * 11 January 1942: Sortie for the

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. (''No. 34'', ''No. 1'' and ''No. 2'') * 31 January 1942: Sortie for the Battle of Ambon. (''No. 34'' and ''No. 39'') * 20 February 1942: Sortie for invasion of Kupang. (''No. 39'', ''No. 1'' and ''No. 2'') * 1 March 1942: Sortie for invasion of

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. (''No. 34'', ''No. 36'', ''No. 37'', ''No. 38'' and ''No. 39'') * 31 March 1942: Sortie for the Battle of Christmas Island. (''No. 34'' and ''No. 36'') * (after): The IJN which finished First Phase Operations allotted them to the convoy escort operations. Only ''No. 36'' was survived war.

Ships in classes

''No. 31'' class

''No. 46'' class

''No. 40'' to ''No. 45'' were a space to the vessels numbers. These numbers were going to be given to all of ''Wakatake''s.

Photos

Image:Japanese No31-class patrol boat.jpg, ''No. 31''-class in September 1942 Image:Japanese patrol boat PB31.jpg, ''No. 31'' on 30 March 1944 at Palau Image:Japanese patrol boats 32 and 33.jpg, ''No. 32'' and ''No. 33'' at Wake Island (left to right) Image:USMC-M-Wake-17.PNG, ''No. 33'' at Wake Island Image:Japanese Patrol Boat No.39 sinking after being torpedoed on 23 April 1943.jpg, ''No. 39'' on 23 April 1943 Image:IJN No46 patrol boat in 1940.jpg, ''No. 46'' in 1940 at Kure Naval Arsenal

Footnotes

Bibliography

*, History of Pacific War Vol.62 ''Ships of the Imperial Japanese Forces'',

Gakken is a Japanese publishing company founded in 1947 by Hideto Furuoka, which also produces educational toys. Their annual sales is reported at ¥ 90 billion ($789 million US). Gakken publishes educational books and magazines and produces other ...

(Japan), January 2008, *Ships of the World special issue Vol.45, ''Escort Vessels of the Imperial Japanese Navy'', , (Japan), February 1996 *The Maru Special, Japanese Naval Vessels No.49, ''Japanese submarine chasers and patrol boats'', (Japan), March 1981 {{DEFAULTSORT:31-class patrol boat World War II naval ships of Japan Momi-class destroyers Wakatake-class destroyers Landing craft Patrol vessels of the Imperial Japanese Navy