Etorofu-class escort ship
The Etorofu-class escort ships (択捉型海防艦 Etorofu-gata kaibōkan) were a group of fourteen kaibōkan escort vessels built for the Imperial Japanese Navy during World War II. Eight of the fourteen ships were sunk during the war. The class was also referred to by internal Japanese documents as the "Modified A-class" coastal defense vessel (甲型海防艦 Kō-gata kaibōkan).
|Preceded by:||Shimushu class|
|Succeeded by:||Mikura class|
|Displacement:||870 long tons (884 t)|
|Length:||77.7 m (255 ft)|
|Beam:||9.1 m (29 ft 10 in)|
|Draught:||3.05 m (10 ft)|
|Speed:||19.7 knots (22.7 mph; 36.5 km/h)|
The Shimushu-class kaibōkan, as with the Chidori class torpedo boat, was a consequence of the 1930 London Naval Treaty, which placed limitations on the total destroyer tonnage the Imperial Japanese Navy was permitted. One way in which the treaty could be circumvented was to use a loophole in the treaty which permitted ships of between 600 and 2,000 tons, with no more than four guns over 76mm, no torpedoes, and with a maximum speed of no more than 20 knots. A new class of vessel was designed to use this loophole, and was given the obsolete designation of kaibōkan (Kai = sea, ocean, Bo = defence, Kan = ship), which had previously been used to designate obsolete battleships which had been reassigned to coastal defense duties. Immediately before the start of then Pacific War, the Imperial Japanese Navy suddenly decided to give more priority to convoy escorts, possibly in light of the ongoing successes of German U-boats against British shipping in the Atlantic. As the Shimushu-class was not suited for mass-production and took too long to build, the 1941 Rapid Naval Armaments Supplement Programme authorized 14 modified versions of the Shimushu-class, which were designated the Etorofu-class.
The Etorofu-class was almost identical to the Shimushu-class but with a simplified bow, stern and bridge structure to facilitate production. The ships measured 77.72 meters (255 ft 0 in) overall, with a beam of 9.1 meters (29 ft 10 in) and a draft of 3.05 meters (10 ft 0 in). They displaced 880 metric tons (870 long tons) at standard load and 1,040 metric tons (1,020 long tons) at deep load. The ships had two diesel engines, each driving one propeller shaft, which were rated at a total of 4,200 brake horsepower (3,100 kW) for a speed of 19.7 knots (36.5 km/h; 22.7 mph). The ships had a range of 8,000 nautical miles (15,000 km; 9,200 mi) at a speed of 16 knots (30 km/h; 18 mph).
As with the Shimushu-class the main battery of the Etorofu-class consisted of three Type 3 120-millimeter (4.7 in) guns in single mounts, one superfiring pair aft and one mount forward of the superstructure. Anti-aircraft protection was by four Type 96 25-millimeter (1.0 in) anti-aircraft guns in two twin-gun mounts abreast the bridge. However, for a ship supposedly designed for convoy escort, only one Model 94 depth charge launcher was installed on the quarterdeck along with a Model 3 loading frame. The number of depth charges was initially 36, but this was increased to 60 while the ships were still in production, which necessitated the deletion of the two paravanes initially in the design for minesweeping. The ships were also equipped with a Model 93 sonar and a Type 93 hydrophone.
During the Pacific War, the number of Type 96 anti-aircraft gun was increased to five triple-mounts and a varying number of single-mounts, up to 15 in total by August 1943. A Type 22 and Type 13 radar were also installed. Aa Type 97 81-millimeter (3.2 in) trench mortar was also installed front of the bridge
The Etorofu-class proved to be an inadequate design by the time the final units entered service in 1944. Their speed was slower than most submarines, and with only one depth charge projector, their combat capability against the increasingly effective United States Navy submarine forces was ineffective. The Etorofu-class vessels were mostly deployed to the South China Sea or East China Sea as convoy escorts, but few recorded any attacks against Allied submarines. Conversely, six of the 14 ships in the class were sunk by American submarines. Of the six survivors, three were used as repatriation ships after the war, and were subsequently given as prize of war to Allied navies.
Ships in class
|択捉||Etorofu||Hitachi-Sakurajima Shipyards||23 Feb 1942||29 Jan 1943||15 May 1943||Ceded to the United States, 1946. Scrapped 1947|
|松輪||Matsuwa||Mitsui-Tamano Shipyards||20 Apr 1942||13 Nov 1942||23 Mar 1943||Sunk by USS Harder on 22 Aug 1944, Hidai Bay, Philippines [14-15N, 120-25E]|
|佐渡||Sado||NKK-Tsurumi Shipyards||21 Feb 1942||28 Nov 1942||27 Mar 1943||Sunk by USS Haddo on 22 Aug 1944, Hidai Bay, Philippines [14-15N, 120-25E]|
|隠岐||Oki||Uraga Dock Company||27 Feb 1942||20 Oct 1942||28 Mar 1943||Ceded to ROCN as Gu An (固安) in Aug 1947, |
captured by PLAN and renamed Chang Bai (长白) in 1949, scrapped 1982
|六連||Mutsure||Hitachi-Sakurajima Shipyards||25 Jul 1942||10 Apr 1943||31 Jul 1943||Sunk by USS Snapper on 2 Sep 1943, Philippine Sea [08-40N, 151-31E]|
|壱岐||Iki||Mitsui-Tamano Shipyards||2 May 1942||5 Feb 1943||31 Ma7 1943||Sunk by USS Raton on 24 May 1944, 150 miles W of Sarawak|
|対馬||Tsushima||NKK-Tsurumi Shipyards||20 Jun 1942||20 Mar 1943||28 Jul 1943||Ceded to ROCN as Lin An (臨安) 31 July 1947, scrapped 1963|
|若宮||Wakamiya||Mitsui-Tamano Shipyards||16 Jul 1942||19 Apr 1943||10 Aug 1943||Sunk by USS Gato on 24 May 1944, East China Sea [28-38N, 122-05E]|
|平戸||Hirato||Hitachi-Sakurajima Shipyards||2 Nov 1942||30 Jun 1943||28 Sep 1943||Sunk by USS Growler on 12 Sep 1944, South China Sea [17-54N, 114-49]|
|福江||Fukue||Uraga Dock Company||30 Oct 1942||2 Apr 1943||28 Jun 1943||Ceded to UK in July 1947, scrapped|
|天草||Amakusa||Hitachi-Sakurajima Shipyards||5 Apr 1943||30 Sep 1943||20 Nov 1943||Sunk by Royal Navy aircraft 9 Aug 1945, Onagawa, Japan|
|満珠||Manju||Mitsui-Tamano Shipyards||15 Feb 1943||31 Jul 1943||30 Nov 1943||Scrapped 1946|
|干珠||Kanju||Uraga Dock Company||8 Apr 1943||7 Aug 1943||30 Oct 1943||Scuttled after mine damage, 15 Aug 1945, near Wonson, Korea [39-10N, 127-27E.]|
|笠戸||Kasado||Uraga Dock Company||10 Aug 1943||9 Dec 1943||27 Feb 1944||Scrapped 1948|
- Stille, Mark (2017). Imperial Japanese Navy Antisubmarine Escorts 1941–45. Oxford, UK: Osprey Publishing. p. 20-24. ISBN 978 1 4728 1817 1.
- Chesneau, p. 205
- Jentschura, Jung & Mickel, p. 187
- Chesneau, Roger, ed. (1980). Conway's All the World's Fighting Ships 1922–1946. Greenwich, UK: Conway Maritime Press. ISBN 0-85177-146-7.
- Jentschura, Hansgeorg; Jung, Dieter & Mickel, Peter (1977). Warships of the Imperial Japanese Navy, 1869–1945. Annapolis, Maryland: United States Naval Institute. ISBN 0-87021-893-X.
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