Ukuru-class escort ship

UKU in 1944
Class overview
Operators:	Imperial Japanese Navy  Republic of China Navy  People's Liberation Army Navy
Preceded by:	Mikura-class
Succeeded by:	C Type-class
Built:	1942–1944
In commission:	1943–1964
Planned:	142
Completed:	29
Lost:	10
General characteristics
Type:	Escort vessel
Displacement:	940 long tons (955 t) standard
Length:	77.7 m (255 ft) 258.4
Beam:	9.1 m (29 ft 10 in) 29.10
Draught:	3.05 m (10 ft) 10
Propulsion:	2 shaft, geared diesel engines, 4,400 hp (3,281 kW)
Speed:	19.5 knots (22.4 mph; 36.1 km/h)
Range:	5,000 nmi (9,300 km) at 16 kn (18 mph; 30 km/h)
Complement:	150
Sensors and processing systems:	Type 22 and 13 radars Type 93 and/or Type 3 sonar
Armament:	As built : 3 × 120 mm (4.7 in)/45 cal DP guns 4 × 25 mm (0.98 in) AA machine guns (2×2) 2 × Type 94 depth charge projectors 16 × Type 3 depth charge throwers 2 × depth charge chutes 120 × depth charges From 1944 : 3 × 120 mm (4.7 in)/45 cal DP guns 16-20 × 25 mm (0.98 in) AA machine guns 2 × Type 94 depth charge projectors 16 × Type 3 depth charge throwers 2 × depth charge chutes 120 × depth charges 1 × 80 mm (3.1 in) mortar

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 ships in the service of the Imperial Japanese Navy during World War II.

The Japanese called these ships Kaibōkan, "ocean defence ships" (Kai = sea, ocean, Bō = defense, Kan = ship), a name used to denote a multi-purpose vessel.^[1] The twenty-nine ships of the Ukuru class were a major part of Japan's escort force from the middle of World War II. They were denoted "Modified Type B"(改乙型 (Kai-Otsu-gata)) ships, and they were the fourth class of Kaibokan.

The Ukurus, like the Mikura-class, were dedicated to the anti-aircraft and anti-submarine role. The Ukuru class was a further simplification of the Mikura design. The Ukurus were constructed using prefabricated sections that enabled them to be built in as little as four months. 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 the USS Crevalle and striking a mine as well.

The Ukuru class was initially armed with 120 depth charges with 2 Type 94 depth charge projectors, sixteen Type 3 depth charge throwers and two depth charge chutes and would later receive an 8 cm trench mortar. The number of AA machine guns was increased to 16 to 20 25mm. They received Type 22 and Type 13 radars, and Type 93 or Type 3 sonar in 1943-1944.

Okinawa was the most successful ship of the class, helping to sink two US submarines, the USS Snook on April 14, 1945 with the kaibokans CD-8, CD-32, and CD-52; and USS Bonefish on June 19, 1945 with kaibokans CD-63, CD-75, CD-158, and CD-207

Ships

There were 29 ships completed of 142 planned.

• Ukuru (鵜来), constructed at Nihon Kokan, Tsurumi, laid down on October 9, 1943, launched on May 15, 1944, and commissioned on July 31, 1944. Ukuru survived the war and later became a weather survey ship in the Japanese Maritime Transport Bureau before being sold for scrapping on November 24, 1965. Her hull number PL104 is seen in a scene in the 1961 classic Japanese movie "Mothra".
• Hiburi (日振), constructed at Hitachi, Sakurajima, laid down on January 3, 1944, launched on April 10, 1944, and commissioned on June 27, 1944. Hiburi was torpedoed and sunk by the USS Harder on August 22, 1944 with 154 killed and wounded.
• Shonan (昭南), constructed at Hitachi, Sakurajima, laid down on February 23, 1944, launched on May 19, 1944, and commissioned on July 13, 1944. Shonan was torpedoed and sunk by the USS Hoe on February 25, 1945 with 198 crew and passengers killed.
• Daito (大東), constructed at Hitachi, Sakurajima, laid down on February 23, 1944, launched on June 24, 1944, and commissioned on August 7, 1944. Daito survived the war, but was lost while minesweeping shortly after the war ended on November 16, 1945.
• Okinawa (沖縄), constructed at Nihon Kokan, Tsurumi, laid down on December 10, 1943, launched on June 19, 1944, and commissioned on August 16, 1944. Okinawa was damaged by a bomb in an air attack by P-38s while escorting TA no. 2 on November 5, 1944 and damaged by PT boats on November 9 and by aircraft again on November 18, 1944. Okinawa was sunk on July 30, 1945 by aircraft from HMS Formidable.
• Kume (久米), constructed at Hitachi, Sakurajima, laid down on May 26, 1944, launched on August 15, 1944, and commissioned on September 25, 1944. Kume was torpedoed and sunk by the USS Spadefish with the loss of 89 men.
• Ikuna (生名), constructed at Hitachi, Sakurajima, laid down on June 30, 1944, launched on September 4, 1944, and commissioned on October 15, 1944. Ikuna was hit by a torpedo by USS Crevalle and damaged on April 10, 1945. On August 1, 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 May 25, 1963.
• Shinnan (新南), constructed at Uraga dock, laid down on June 30, 1944, launched on September 4, 1944, and commissioned on October 21, 1944. Shinnan 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.
• Yaku (屋久), constructed at Uraga dock, laid down on June 30, 1944, launched on September 4, 1944, and commissioned on October 23, 1944. Yaku was torpedoed and sunk by the USS Hammerhead with the loss of 132 men.
• Aguni (粟国), constructed at Nihon Kokan, Tsurumi, laid down on February 15, 1944, launched on September 21, 1944, and commissioned on December 2, 1944. On May 27, 1945, Aguni was damaged by a Bat glide bomb. The bomb's 1,000-lb 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 remains navigable and proceeds stern first to Pusan, Korea on her own power. Aguni survived the war and was sold for scrapping on May 20, 1948.
• Mokuto (目斗), constructed at Hitachi, Sakurajima, laid down on November 5, 1944, launched on January 7, 1945, and commissioned on February 19, 1945. On April 4, 1945, Mokuto struck a mine and sank.
• Inagi (稲木), constructed at Mitsui, Tamano, laid down on May 15, 1944, launched on September 25, 1944, and commissioned on December 16, 1944. Inagi was bombed and sunk by planes from HMS Formidable on August 9, 1945 with the loss of 29 killed and 35 wounded.
• Uku (宇久), constructed at Sasebo Navy Yard, laid down on August 1, 1944, launched on November 12, 1944, and commissioned on December 30, 1944. Uku 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.
• Chikubu (竹生), constructed at Uraga dock, laid down on September 8, 1944, launched on November 24, 1944, and commissioned on December 31, 1944. Chikubu survived the war and later became a weather survey ship in the Japanese Maritime Transport Bureau before being sold for scrapping on October 4, 1962.
• Habushi (羽節), constructed at Mitsui, Tamano, laid down on August 20, 1944, launched on November 20, 1944, and commissioned on January 10, 1945. Habushi struck a mine on April 8, 1945 and was damaged. She survived the war and was ceded to the United States as a war reparation and scrapped starting October 17, 1947.
• Sakito (崎戸), constructed at Hitachi, Sakurajima, laid down on September 7, 1944, launched on November 29, 1944, and commissioned on January 10, 1945. On June 27, 1945, Sakito struck a mine and was damaged. Sakito survived the war and was scrapped on December 1, 1947.
• Kuga (久賀), constructed at Sasebo Navy Yard, laid down on August 1, 1944, launched on November 19, 1944, and commissioned on January 25, 1945. Kuga struck a mine on June 25, 1945 and was damaged. She survived the war and was scrapped on June 30, 1947.
• Ojika (男鹿), constructed at Mitsui, Tamano, laid down on September 7, 1944, launched on December 30, 1944, and commissioned on February 21, 1945. Ojika was torpedoed and sunk by the USS Springer on June 2, 1945.
• Kozu (神津), constructed at Uraga dock, laid down on October 20, 1944, launched on December 31, 1944, and commissioned on February 7, 1945. She survived the war and was ceded to the Soviet Union as a war reparation on August 28, 1947. Served in Soviet Pacific Ocean Fleet as patrol ship EK-47 (1947), oceanorgaphic research ship Nord (1948), later - Glubomer (1953), repair ship PM-62 (1955). Decommissioned on January 25, 1969 and scrapped.
• Kanawa (金輪), constructed at Mitsui, Tamano, laid down on November 15, 1944, and commissioned on March 25, 1945. Kanawa survived the war and was ceded to the UK as a war reparation and scrapped on August 14, 1947.
• Shiga (志賀), constructed at Sasebo Navy Yard, laid down on November 25, 1944, launched on February 9, 1945, and commissioned on March 20, 1945. Shiga 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.^[2]
• Amami (奄美), constructed at Nihon Kokan, Tsurumi, laid down on February 14, 1944, launched on November 30, 1944, and commissioned on April 8, 1945. Amami survived the war and was ceded to the UK as a war reparation and scrapped on December 20, 1947.
• Hodaka (保高), constructed at Uraga dock, laid down on November 27, 1944, launched on January 28, 1945, and commissioned on March 30, 1945. She survived the war and was ceded to the United States as a war reparation and scrapped starting March 1, 1948.
• Habuto(波太), constructed at Hitachi, Sakurajima, laid down on December 3, 1944, launched on February 28, 1945, and commissioned on April 7, 1945. Habuto struck a mine on June 6, 1945 and was damaged. She struck a second mine on June 10, 1945 and was again damaged. She survived the war and was ceded to the UK as a war reparation and scrapped on July 16, 1947.
• Iwo (伊王), constructed at Maizuru Navy Yard, laid down on November 25, 1944, launched on February 12, 1945, and commissioned on March 24, 1945. Iwo struck a mine on June 13, 1945 and was damaged. She was damaged lightly in an air attack by planes from the USS Shangri-La, losing 4 killed and 61 wounded. She survived the war and was scrapped starting July 2, 1948.
• Takane (高根), constructed at Mitsui, Tamano, laid down on December 15, 1944, launched on February 13, 1945, and commissioned on April 26, 1945. Takane survived the war and was scrapped starting November 27, 1947.
• Ikara (伊唐), constructed at Uraga dock, laid down on December 26, 1944, launched on February 22, 1945, and commissioned on April 30, 1945. On August 9, 1945, Ikara struck a mine and sank.
• Shisaka (四阪), constructed at Hitachi, Sakurajima, laid down on August 21, 1944, launched on October 31, 1944, and commissioned on December 15, 1944. She survived the war and was ceded to the ROCN war reparation and named 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 early 1980s before it as finally scrapped.
• Ikuno (生野), constructed at Uraga dock, laid down on January 3, 1945, launched on March 11, 1945, and commissioned on July 17, 1945. She survived the war and was ceded to the Soviet Union as a war reparation on July 29, 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 June 1, 1961 and scrapped.

See also

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

Notes

1. Worth p. 208
2. http://www.combinedfleet.com/Shiga_t.htm

References

• http://www.combinedfleet.com/Kaibokan.htm (Retrieved April 30, 2009)
• http://homepage2.nifty.com/nishidah/e/stc0705.htm (Retrieved April 30, 2009)
• http://www.warshipsww2.eu/lode.php?language=E&period=&idtrida=1094 (Retrieved April 30, 2009)
• Worth, Richard, Fleets of World War II, Da Capo Press (2001), ISBN 0-306-81116-2