# Ōtori-class torpedo boat

The Ōtori-class torpedo boat (鴻型水雷艇, Ōtori-gata suiraitei) were a class of eight fast torpedo boats of the Imperial Japanese Navy built before and operated during World War II.

## Development

To circumvent the terms of the 1930 London Naval Treaty, which limited its total destroyer tonnage the Imperial Japanese Navy designed the Chidori class torpedo boat, but planned to arm it with half the armament of a Fubuki class destroyer. The resultant design was top-heavy and unstable, resulting in the 1934 Tomozuru Incident, in which one of the Chidori-class vessels capsized. The subsequent investigation revealed the fundamental design flaw, and the four vessels in the class which had been completed were extensively rebuilt, and the remaining sixteen vessels projected were cancelled in favor of a new design which would address these design issues from the beginning. Sixteen Ōtori-class vessels were ordered in the 1934 2nd Naval Armaments Supplement Programme, of which eight were completed between 1936 and 1937. The remaining eight were cancelled in favor of building additional submarine chasers.

## Design

Benefiting from the redesign of the Chidori-class, the Ōtori-class had a slightly longer hull with an increased beam. The bridge structure was also lower than on the Chidori-class to help keep the center-of-gravity low. Two Kampon geared turbines powered by two Kampon water-tube boilers produced a total of 19,000 shaft horsepower (14,000 kW), which gave the ships more power than the Chidori-class, and thus a slightly higher maximum speed of 30.0 knots (34.5 mph; 55.6 km/h)
The armament of the Ōtori-class was almost the same as for the rebuilt Chidori-class with a main battery of three single 12 cm/45 3rd Year Type naval guns which could elevate to 55 degrees for a limited anti-aircraft capability. The torpedo mount was upgraded from a twin to a triple torpedo launcher, and a single Type 94 depth charge launcher was carried. However, anti-aircraft weaponry was only a single license-built Vickers 40 mm (2 pounder pom pom).
During the Pacific War, in 1944 survivors had the aft gun removed, and up to three twin-mount and five single-mount Type 96 25mm AA guns were installed as well as a Type 22 and a Type 13 radar. The number of depth charges was increased to 48.

## Operational service

The Ōtori-class were used extensively from the start of the Pacific War to escort invasion convoys to the Philippines, Dutch East Indies and the Solomon Islands. Hiyodori sank the USS Amberjack (SS-219) during the Solomon Islands campaign on 16 February 1943. Seven of the eight ships in the class were sunk by submarines or air attack in the Pacific or the South China Sea and only Kiji survived to the end of the war.

## Ships in class

| Ship | Kanji | Builder | Laid down | Launched | Completed | Fate |
| Ōtori | 鴻, 'stork' | Maizuru Naval Arsenal | 8 Nov 1934 | 25 Apr 1935 | 10 Oct 1936 | Sunk by aircraft of Task Force 58 NW of Saipan, 12 Jun 1944 |
| Hiyodori | 鵯, 'brown-eared bulbul' | Ishikawajima Shipyards | 26 Nov 1934 | 25 Oct 1935 | 20 Dec 1936 | Sunk by USS Gunnel in South China Sea, 17 Nov 1944 |
| Hayabusa | 隼, 'peregrine falcon' | Yokohama Dock Company | 19 Dec 1934 | 28 Oct 1935 | 7 Dec 1936 | Sunk by aircraft in Sibuyan Sea, 24 Sep 1944 |
| Kasasagi | 鵲, 'magpie' | Ōsaka Iron Works | 4 Mar 1935 | 18 Oct 1935 | 15 Jan 1937 | Sunk by USS Bluefish in Flores Sea, 26 Sep 1943 |
| Kiji | 雉, 'pheasant' | Mitsui Engineering & Shipbuilding, Tamano | 24 Oct 1935 | 26 Jan 1937 | 31 Jul 1937 | Surrendered to Soviet Union at Nakhodka, on 3 Oct 1947; Renamed Vnimatel'nyy; Decommissioned 31 Oct 1957 |
| Kari | 雁, 'wild goose' | Yokohama Dock Company | 11 May 1936 | 20 Jan 1937 | 20 Sep 1937 | Sunk by USS Baya in Java Sea, 16 July 1945 |
| Sagi | 鷺, 'snowy heron' | Harima Shipyards | 20 May 1936 | 30 Jan 1937 | 31 Jul 1937 | Sunk by USS Gunnel W of Luzon, 8 Nov 1944 |
| Hato | 鳩, 'dove' | Ishikawajima Shipyards | 28 May 1936 | 25 Jan 1937 | 7 Aug 1937 | Sunk by aircraft at Hong Kong, 16 Oct 1944 |
| Hatsutaka | 初鷹 | — | — | — | — | Cancelled, 1937 |
| Aotaka | 蒼鷹 | — | — | — | — | Cancelled, 1937 |
| Wakataka | 若鷹 | — | — | — | — | Cancelled, 1937 |
| Kumataka | 熊鷹 | — | — | — | — | Cancelled, 1937 |
| Yamadori | 山鳥 | — | — | — | — | Cancelled, 1937 |
| Mizutori | 水鳥 | — | — | — | — | Cancelled, 1937 |
| Umidori | 海鳥 | — | — | — | — | Cancelled, 1937 |
| Komadori | 駒鳥 | — | — | — | — | Cancelled, 1937 |