Japanese escort ship Etorofu 1943.jpg
Etorofu in 1943
Class overview
Preceded by Shimushu class
Succeeded by Mikura class
General characteristics
TypeEscort vessel
Displacement870 long tons (884 t)
Length77.7 m (255 ft)
Beam9.1 m (29 ft 10 in)
Draught3.05 m (10 ft)
Speed19.7 knots (22.7 mph; 36.5 km/h)

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).


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 76 mm (3 in), no torpedoes, and with a maximum speed of no more than 20 knots (37 km/h; 23 mph). 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 thirty modified versions of the Shimushu class, which were designated the Etorofu class. [1] However, sixteen of the projected thirty ships were subsequently re-ordered to the subsequent Mikura, Hiburi or Ukura designs.

Production began between February 1942 and August 1943. Despite simplification, the design was still too complex for mass production and one of the ships was not completed until early 1944.[1]


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).[2] 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).[3]

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.[1]

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[3]

Operational service

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.[1]

Ships in class

Thirty ships (numbered #310 to #339) were included in the Rapid Naval Armaments Supplement Programme in 1941. These are listed below with the shipyard to which each was allocated:

While fourteen of the above ships were completed to the Etorofu design, eight ships - Mikura (#320), Miyake (#322), Awaji (#324), Nōmi (#326), Kurahashi (#327), Chiburi (#329), Yashiro (#331) and Kusagaki (#334) - were altered to be built to the Mikura design; three ships - Hiburi (#328), Daitō (#333) and Shōnan (#339) - were altered to be built to the Hiburi design; and five ships - Ukuru (#332), Okinawa (#335), Amami (#336), Aguni (#337) and Shinnan (#338) - were altered to be built to the 'Ukuru design. The fourteen completed to the (original) Etorofu design were as follows:

Kanji Name Builder Laid down Launched Completed Fate
択捉 Etorofu Hitachi-Sakurajima Shipyards 23 February 1942 29 January 1943 15 May 1943 Ceded to the United States, 1946. Scrapped 1947
松輪 Matsuwa Mitsui-Tamano Shipyards 20 April 1942 13 November 1942 23 March 1943 Sunk by USS Harder on 22 August 1944, Hidai Bay, Philippines [14-15N, 120-25E]
佐渡 Sado NKK-Tsurumi Shipyards 21 February 1942 28 November 1942 27 March 1943 Sunk by USS Haddo on 22 August 1944, Hidai Bay, Philippines [14-15N, 120-25E]
隠岐 Oki Uraga Dock Company 27 February 1942 20 October 1942 28 March 1943 Ceded to Republic of China Navy as Gu An (固安) in August 1947,
captured by PLAN and renamed Chang Bai (长白) in 1949, scrapped 1982
六連 Mutsure Hitachi-Sakurajima Shipyards 25 July 1942 10 April 1943 31 July 1943 Sunk by USS Snapper on 2 September 1943, Philippine Sea [08-40N, 151-31E]
壱岐 Iki Mitsui-Tamano Shipyards 2 May 1942 5 February 1943 31 May 1943 Sunk by USS Raton on 24 May 1944, 150 miles W of Sarawak
対馬 Tsushima NKK-Tsurumi Shipyards 20 June 1942 20 March 1943 28 July 1943 Ceded to Republic of China Navy as Lin An (臨安) 31 July 1947, scrapped 1963
若宮 Wakamiya Mitsui-Tamano Shipyards 16 July 1942 19 April 1943 10 August 1943 Sunk by USS Gato on 24 May 1944, East China Sea [28-38N, 122-05E]
平戸 Hirado Hitachi-Sakurajima Shipyards 2 November 1942 30 June 1943 28 September 1943 Sunk by USS Growler on 12 September 1944, South China Sea [17-54N, 114-49]
福江 Fukae[4] Uraga Dock Company 30 October 1942 2 April 1943 28 June 1943 Ceded to UK in July 1947, scrapped
天草 Amakusa Hitachi-Sakurajima Shipyards 5 April 1943 30 September 1943 20 November 1943 Sunk by Royal Navy aircraft 9 August 1945, Onagawa, Japan
満珠 Manju Mitsui-Tamano Shipyards 15 February 1943 31 July 1943 30 November 1943 Scrapped 1946
干珠 Kanju Uraga Dock Company 8 April 1943 7 August 1943 30 October 1943 Scuttled after mine damage, 15 August 1945, near Wonson, Korea [39-10N, 127-27E.]
笠戸 Kasado Uraga Dock Company 10 August 1943 9 December 1943 27 February 1944 Scrapped 1948


  1. ^ a b c d Stille, Mark (2017). Imperial Japanese Navy Antisubmarine Escorts 1941–45. Oxford, UK: Osprey Publishing. p. 20-24. ISBN 978 1 4728 1817 1.
  2. ^ Chesneau, p. 205
  3. ^ a b Jentschura, Jung & Mickel, p. 187
  4. ^ Often spelled incorrectly Fukue in English literature.