Hiburi-class escort ship explained

The was a sub-class of the s of the Imperial Japanese Navy (IJN), serving during and after World War II.^[1]

Background

In the Rapid Naval Armaments Supplement Programme of 1941, the Imperial Japanese Navy ordered the construction of thirty escort vessels (kaibōkan) – designated as #310 to #339 of that Programme, to provide escort ships for the Navy. Fourteen of these were planned as (Escort ship Type-A) of 860 tons standard displacement and sixteen as (Escort ship Type-B) of 940 tons, although in the Budget (for which 153,360,000 yen was provided for the ships, or 5,112,000 per ship) they were all stated to be of 1,200 tons. However, three of the Mikura class (ships #328, #333 and #339) were subsequently designated as to be built to the Hiburi design.

In the next year's Modified 5th Naval Armaments Supplement Programme, the IJN ordered the construction of another thirty-four ships to a modified version of the Type-B design; these were designated as #5251 to #5284 of that Programme. However, eight of these ship (ships #5252, #5254, #5257, ##5259 and #5263 to #5266) were subsequently designated to be built to the Hiburi design. Only six of the eight were so completed, with #5265 and #5266 being incomplete at the end of the Pacific War and broken up.

The eleven ships were all ordered from the Hitachi Zōsen shipbuilding concern at Sakurajima, which had also received other orders for ships completed to the Etorofu, Mikura and Ukuru designs. The Hiburi design used the same hull as the Ukuru class, but with different fittings. In 1943, the Japanese Navy General Staff (Gunreibu) promoted the building of Escort ship Type-A, the and Escort ship Type-B, the and . However, the Navy General Staff also noted that too many man-hours of work were needed for their building.

Design

• The Navy Technical Department (Kampon) used the Ukurus basic designs for the new drawings. It was a chimera of Mikura and Ukuru classes.
• The new drawings had the following characteristic.
  • Armaments and under waterline designs were same as Mikura.
  • Everything else was same as in the Ukuru.
• The Kampon estimated man-hours for building will be between 42,000 to 40,000.^[2]
• The new drawing was sent to the Hitachi Zōsen Corporation, Sakurajima Shipyard. Those ships of the Mikura class and the Ukuru class that had not been started were converted to the Hiburi class. The Hitachi Zōsen built all of the Hiburi class vessels.^[3]

Ships in class

Of the nine ships completed, three were sunk by US submarines and two by naval mines.

Ship #	Ship	Laid down	Launched	Completed	Fate
328		3 January 1944	10 April 1944	27 June 1944	Sunk by USS Harder at west of Manila, 22 August 1944.
333		17 April 1944	24 June 1944	7 August 1944	Sunk by naval mine at Tsushima Strait, 16 November 1945.
339		23 February 1944	19 May 1944	13 July 1944	Sunk by USS Hoe at south of Hainan Island, 25 February 1945.
5252		26 May 1944	15 August 1944	25 September 1944	Sunk by USS Spadefish at Yellow Sea 33.9°N 177°W, 28 January 1945.
5254		30 June 1944	4 September 1944	15 October 1944	Decommissioned on 30 November 1945. Transferred to Meteorological Agency 26 December 1947, and renamed Ikuna-maru. Transferred to Maritime Safety Agency 1 January 1949, and renamed Ojika (PS-102). Decommissioned on 25 May 1963.
5257		21 August 1944	31 October 1944	15 December 1944	Decommissioned on 15 September 1945. Surrendered to Republic of China on 6 July 1947, and renamed Huian. Defected to People's Liberation Army 23 April 1949. Sunk by aircraft at Yanziji, 28 April 1949. Repairs were completed on 24 December 1953, and given the pennant number 218. Decommissioned in 1990.
5259		7 September 1944	29 November 1944	10 January 1945	Decommissioned on 20 November 1945. Scrapped January 1947.
5263		5 November 1944	7 January 1945	19 February 1945	Sunk by naval mine at Kanmon Straits, 4 April 1945.
5264		3 December 1944	28 February 1945	7 April 1945	Decommissioned on 23 October 1945. Surrendered to United Kingdom on 16 July 1947, later scrapped.
5265		12 January 1945	10 May 1945		Not completed by the end of the war (95%). Scrapped on 25 March 1948.
5266	^[4]	5 March 1945			Not completed by the end of the war (20%). Scrapped on 23 October 1947.

Appendix

• Classification of the Kaibōkan classes in IJN official documents
  • The Shimushu, Etorofu, Mikura, Hiburi and Ukuru were classed in the Shimushu class.
  • The IJN changed their classification on 5 June 1944, because the shipyards and commanders were confused.
  • The Escort ship Type-B and Modified Type-B were combined to the Escort ship Type-A, and Type-Bs became extinct thereby.

Before 5 June 1944				And after 5 June 1944
Plan names	Official class names	Common class names	Plan name	Official class names	Common class names
Type-A	Shimushu class	Shimushu class	Type-A	Shimushu class	Shimushu class
		Etorofu class			Etorofu class
Type-B		Mikura class		Mikura class	Mikura class
		Hiburi class			Hiburi class
Modified Type-B		Ukuru class		Ukuru class	Ukuru class
Type-C	No.1 class	No.1 class	Type-C	No.1 class	No.1 class
Type-D	No.2 class	No.2 class	Type-D	No.2 class	No.2 class

Gallery

(Changes of equipment and under waterline design)

See also

• Shimushu-class escort ship
• Etorofu-class escort ship
• Mikura-class escort ship
• Ukuru-class escort ship
• Type C escort ship
• Type D escort ship
• Destroyer escort
• Tacoma-class frigate
• Flower-class corvette

Bibliography

• Web site: Rekishi Gunzō., History of Pacific War Vol.51, The truth histories of the Imperial Japanese Vessels Part.2, Gakken (Japan), June 2002,
• Ships of the World special issue Vol.45, Escort Vessels of the Imperial Japanese Navy, Web site: Kaijinsha., (Japan), February 1996
• Model Art Extra No.340, Drawings of Imperial Japanese Naval Vessels Part-1, Web site: Model Art Co. Ltd.. (Japan), October 1989
• The Maru Special, Japanese Naval Vessels No.28, Japanese escort ships, Web site: Ushio Shobō. (Japan), June 1979

Notes and References

1. The 11 vessels described in this article are classified to the in many books, because the Hiburi class closely resembles the Ukuru class. The IJN's official documents, however, call them the Mikura class.
2. This value was reduced to around 35,000 man-hours by an effort of the shipyard.
3. Therefore Hitachi Zōsen did not participate in building of the Ukuru class.
4. Web site: Tomoshiri Island.