Ukuru-class escort ship

Last updated
IJN escort vessel UKU in 1944.jpg
Uku in 1944
Class overview
NameUkuru class
Operators
Preceded by Mikuraclass
Succeeded by Type C Type D
Subclasses Hiburi-class escort ship
Built1942–1944
In commission1943–1964
Planned142
Completed29
Cancelled2
Lost10
General characteristics
TypeEscort vessel
Displacement940 long tons (955 t) standard
Length77.7 m (255 ft) 258.4
Beam9.1 m (29 ft 10 in) 29.10
Draught3.05 m (10 ft) 10
Propulsion2 shaft, geared diesel engines, 4,400 hp (3,281 kW)
Speed19.5 knots (22.4 mph; 36.1 km/h)
Range5,000  nmi (9,300 km) at 16 kn (18 mph; 30 km/h)
Complement150
Sensors and
processing systems
  • Type 22 and 13 radars
  • Type 93 and/or Type 3 sonar
Armament
Shiga in 1988. Made based on National Land Image Information (Color Aerial Photographs), Ministry of Land, Infrastructure, Transport and Tourism Escort ship Shiga aerial photograph.jpg
Shiga in 1988. Made based on National Land Image Information (Color Aerial Photographs), Ministry of Land, Infrastructure, Transport and Tourism

The Ukuru-class escort ships (鵜来型海防艦, Ukuru-gata kaibōkan) were a class of twenty kaibōkan escort vessels built for the Imperial Japanese Navy during World War II. [1] The class was also referred to by internal Japanese documents as the "Modified B-class" coastal defense vessel (改乙型海防艦, Kai-Otsu-gata kaibōkan), and they were the fourth class of kaibōkan .

Contents

Background

The Mikuraclass escort ship was developed after the start of the Pacific War, it became apparent that a design more capable of anti-submarine warfare than the previous Shimushu and Etorofuclass kaibōkan was needed. Despite being a simplified design, the Mikura-class vessels still took too long to construct, and due to the high attrition of Japan's destroyer and escort ships, action needed to be urgently taken to produce more ships in a quicker time. Furthermore, operational experience had shown that the Mikura-class was still very weak in its anti-aircraft capability.

The first five of the new Ukuru-class were authorized under the 1941 Rapid Naval Armaments Supplement Programme and an additional six in the 1942 Modified 5th Naval Armaments Supplement Programme and nine under the 1944 Wartime Naval Armaments Supplement Programme. Twenty vessels were commissioned; two more (Urumi and Murotsu) were launched by Uraga Dock and completed in August 1945 but were still uncommissioned by the war’s end. In addition to these, nine units and two additional unfinished ships belong to a sub-class called the Hiburi class [2] and are included in the table below.

Description

The Ukuru-class was a further simplification of the Mikura design. The hull was constructed using prefabricated sections which avoided the use of shaped steel or curved plates, which greatly reduced construction time. The curved plates on the bridge were also eliminated, and the smoke stacks were made of hexagonal elements instead of with a circular or oval cross-section. Internally, individual crew quarters were eliminated, becoming a communal area, and overall the construction was very spartan. These changes reduced construction time to under four months, although construction was often hindered by the lack of diesel engines. [2]

The main battery was the same as on the Mikura-class, with three dual-purpose Type 10 120 mm AA guns one forward, and a twin mount aft, but the later ships in the class were fitted with modified gun shields. Anti-aircraft protection was by five triple-mount Type 96 25-millimeter (1.0 in) anti-aircraft guns with two abreast the bridge, one of each side of the smokestack, and one aft on the deck house, along with a single-mount in front of the bridge. Some units received additional single-mount Type 96s, which were located on the forecastle. The Ukuru-class was equipped with the Type 22 and Type 13 radar. The Ukuru class was initially armed with 120 depth charges with two Type 94 depth charge projectors, sixteen Type 3 depth charge throwers and two depth charge chutes at the stern. The ships were provided with a Model 93 sonar and a Type 93 hydrophone; later units received the Type 3 Model 2 sonar, and some would later receive an 8 cm (3 in) trench mortar. [2]

Initially, the class retained capacity as a minesweeper, and was equipped with two paravanes; however, this was removed soon after completion. [2]

Operational service

Despite being easy to build, they proved quite durable, with 11 occurrences of the class striking mines and only 3 sinking, one of which was after the war. Ikuna survived being torpedoed by USS Crevalle and striking a mine as well.

The Ukuru vessels were used extensively on convoy escort assignment in the South China Sea and East China Sea, where they frequently were attacked by Allied submarines or aircraft. However, despite their durability, they proved to be relatively ineffective against Allied submarines. Okinawa was the most successful ship of the class, helping to sink two US submarines, USS Snook on April 14, 1945 with the kaibōkanCD-8, CD-32, and CD-52; and USS Bonefish on June 19, 1945 with kaibokanCD-63, CD-75, CD-158, and CD-207.

Surviving ships were used in the immediate postwar period as minesweepers and for repatriation. Five vessels survived to return to Japanese control, and were used as weather survey ships or as patrol ships, with the last being retired in 1966. [2]

Ships

NumberKanjiNameBuilderLaid downLaunchedCompletedFate
#328日振HiburiHitachi, Sakurajima3 January 194410 April 194427 June 1944Torpedoed and sunk by USS Harder on 22 August 1944, with 154 killed and wounded.
#332鵜来UkuruNihon Kokan, Tsurumi9 October 194315 May 194431 July 1944Ukuru survived the war and later became a weather survey ship in the Japanese Maritime Transport Bureau before being sold for scrapping on 24 November 1965. [3]
#333大東DaitōHitachi, Sakurajima23 February 194424 June 19447 August 1944Daitō survived the war, but was lost while minesweeping shortly after the war ended on 16 November 1945.
#335沖縄 Okinawa Nihon Kokan, Tsurumi10 December 194319 June 194416 August 1944Okinawa was damaged by a bomb in an air attack by P-38s while escorting TA no. 2 on 5 November 1944 and damaged by PT boats on 9 November and by aircraft again on 18 November 1944. Okinawa was sunk on 30 July 1945 by aircraft from HMS Formidable.
#336奄美AmamiNihon Kokan, Tsurumi14 February 194430 November 19448 April 1945Amami survived the war and was ceded to the UK as a war reparation and scrapped on 20 December 1947.
#337粟国 Aguni Nihon Kokan, Tsurumi15 February 194421 September 19442 December 1944On 27 May 1945, Aguni was damaged by a Bat glide bomb. The bomb's 1,000 lb (450 kg) warhead exploded off Aguni's starboard bow demolishing the whole foredeck area ahead of the bridge and killing 33 sailors. After being hit, Aguni's crew had to cut her anchor chain to free her. Kaibokan CD-12 was dispatched to assist Okinawa in rescuing Aguni’s crew, but despite the heavy damage the kaibokan remained navigable and proceeded stern first to Pusan, Korea on her own power. Aguni survived the war and was sold for scrapping on 20 May 1948.
#338新南ShinnanUraga Dock Company30 June 19444 September 194421 October 1944Shinnan survived the war and later became a weather survey ship in the Japanese Maritime Transport Bureau before being sent to the petrol development agency in October 1967. She was scrapped in 1975.
#339昭南ShōnanHitachi, Sakurajima23 February 194419 May 194413 July 1944Torpedoed and sunk by USS Hoe on 25 February 1945, with 198 crew and passengers killed.
#4701稲木InagiMitsui Zosensho, Tamano15 May 194425 September 194416 December 1944Inagi was bombed and sunk by planes from HMS Formidable on 9 August 1945, with the loss of 29 killed and 35 wounded.
#4702羽節HabushiMitsui Zosensho, Tamano20 August 194420 November 194410 January 1945Habushi struck a mine on 8 April 1945 and was damaged. She survived the war and was ceded to the United States as a war reparation and scrapped starting 17 October 1947.
#4703男鹿OjikaMitsui Zosensho, Tamano7 September 194430 December 194421 February 1945Ojika was torpedoed and sunk by USS Springer on 2 June 1945.
#4704金輪 Kanawa Mitsui Zosensho, Tamano15 November 194420 January 194525 March 1945Kanawa survived the war and was ceded to the UK as a war reparation and scrapped on 14 August 1947.
#4705宇久UkuSasebo Navy Yard1 August 194412 November 194430 December 1944Uku struck a mine on 9 April 1945 and was damaged. She survived the war and was ceded to the United States as a war reparation and later scrapped.
#4707高根TakaneMitsui Zosensho, Tamano15 December 194413 February 194526 April 1945Takane survived the war and was scrapped starting 27 November 1947.
#4709久賀KugaSasebo Navy Yard1 August 194419 November 194425 January 1945Kuga struck a mine on 25 June 1945 and was damaged. She survived the war and was scrapped on 30 June 1947.
#4711志賀ShigaSasebo Navy Yard25 November 19449 February 194520 March 1945Shiga survived the war and later became a weather survey ship in the Japanese Maritime Transport Bureau before being discarded on May 6, 1964. Her hull became the pavilion for Maritime Amusement Park in Chiba City, but her hull deteriorated because of poor maintenance and was dismantled and scrapped in 1998. [4]
#4712伊王IwōMaizuru Navy Yard25 November 194412 February 194524 March 1945Iwo struck a mine on 13 June 1945 and was damaged. She was damaged lightly in an air attack by planes from USS Shangri-La, losing 4 killed and 61 wounded. She survived the war and was scrapped starting 2 July 1948.
#5251屋久YakuUraga Dock Company30 June 19444 September 194423 October 1944Torpedoed and sunk by USS Hammerhead on 23 February 1945, with the loss of 132 men.
#5252久米KumeHitachi, Sakurajima26 May 194415 August 194425 September 1944Torpedoed and sunk by USS Spadefish on 28 January 1945, with the loss of 89 men.
#5253竹生ChikubuUraga Dock Company8 September 194412 November 194431 December 1944Chikubu survived the war and later became a weather survey ship in the Japanese Maritime Transport Bureau before being sold for scrapping on 4 October 1962.
#5254生名IkunaHitachi, Sakurajima30 June 19444 September 194415 October 1944Ikuna was hit by a torpedo by USS Crevalle and damaged on 10 April 1945. On 1 August she struck a mine and was damaged. Ikuna survived the war and later became a weather survey ship in the Japanese Maritime Transport Bureau before being sold for scrapping on 25 May 1963.
#5255神津KōzuUraga Dock Company20 October 194431 December 19447 February 1945She survived the war and was ceded to the Soviet Union as a war reparation on 28 August 1947. Served in Soviet Pacific Ocean Fleet as patrol ship EK-47 (1947), oceanographic research ship Nord (1948), later - Glubomer (1953), repair ship PM-62 (1955). Decommissioned on 25 January 1969 and scrapped.
#5256保高HodakaUraga Dock Company27 November 194428 January 194530 March 1945She survived the war and was ceded to the United States as a war reparation and scrapped starting 1 March 1948.
#5257四阪ShisakaHitachi, Sakurajima21 August 194431 October 194415 December 1944She survived the war and was ceded to the Republic of China Navy as a war reparation and renamed as Huai An (惠安), but later was captured by the Chinese communists at the end of Chinese Civil War, and entered PLAN under the same name. The ship was later renamed as Rui Jin (瑞金) and served as a training ship in PLAN until the early 1980s before it as finally scrapped.
#5258伊唐IkaraUraga Dock Company26 December 194422 February 194530 April 1945On 9 August 1945, Ikara struck a mine and sank.
#5259崎戸SakitoHitachi, Sakurajima7 September 194429 November 194410 January 1945On 27 June 1945, Sakito struck a mine and was damaged. Sakito survived the war and was scrapped on 1 December 1947.
#5260生野IkunoUraga Dock Company3 January 194511 March 194517 July 1945She survived the war and was ceded to the Soviet Union as a war reparation on 29 July 1947. Served in Soviet Pacific Ocean Fleet as patrol ship EK-41 (1947), target ship TsL-41 (1948), oceanographic research ship Val (1949). Decommissioned on 1 June 1961 and scrapped.
#5263目斗MokutoHitachi, Sakurajima5 November 19447 January 194519 February 1945On 4 April 1945, Mokuto struck a mine and sank.
#5264波太HabutoHitachi, Sakurajima3 December 194428 February 19457 April 1945Habuto struck a mine on 6 June 1945 and was damaged. She struck a second mine on 10 June 1945 and was again damaged. She survived the war and was ceded to the UK as a war reparation and scrapped on 16 July 1947.

Twelve other ships were cancelled in 1945 - numbers #4706, #4708, #4710, #4713 to #4721. These included Murotsu and Urumi (both launched but incomplete); also cancelled (unstarted) were #5261, #5262, #5267 to #5284 (all of the Yaku group) from the Modified 5th Naval Armaments Supplement Programme. Also cancelled incomplete were two of the Hiburi class - numbers #5265 (Ōtsu) and #5266 (Tomoshiri).

See also

Notes

  1. Worth p. 208
  2. 1 2 3 4 5 Stille, Mark (2017). Imperial Japanese Navy Antisubmarine Escorts 1941–45. Oxford, UK: Osprey Publishing. p. 30-33. ISBN   978 1 4728 1817 1.
  3. Her hull number PL104 is seen in a scene in the 1961 classic Japanese movie "Mothra".

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References

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