The Momi-class destroyers were a class of twenty-one second-class destroyers of the Imperial Japanese Navy.Jentsura, Warships of the Imperial Japanese Navy, 1869-1945 All were named for plants. Obsolete by the beginning of the Pacific War, the Momis were relegated to mostly secondary roles, with some vessels serving throughout the war as patrol vessels or high speed transports.

Background Construction of the medium-sized Momi-class destroyers was authorized as part of the Imperial Japanese Navy's 8-4 Fleet Program from fiscal 1918–1920, as an accompaniment to the larger with which they shared many common design characteristics.Howarth, The Fighting Ships of the Rising Sun These vessels were produced at several shipyards around Japan, and when formed into attack squadrons of two to four vessels, made up the backbone of the inter-war Imperial Japanese Navy.Globalsecurity.org, IJN Momi class destroyers

The final seven vessels planned for this series were cancelled, and re-ordered as the new s in 1919, and by the mid-1920s the concept of the "second-class destroyer" had fallen out of favor due to the greater capabilities offered by the new generation of fleet destroyers.

Initial design The Momi class was a development of the second-class destroyers, relying on the same basic hull. They were quite small, comparable to Royal Navy corvettes. The design incorporated features discovered on German destroyers awarded as reparations from World War I, including a lengthened forecastle with a break forming a well deck immediately forward of the bridge, and a front gun battery placed on a pedestal on the centerline so that it could be operated in heavy weather. This arrangement also offered the advantage of a low, semi protected area for the forward torpedo tubes albeit at the cost of becoming awash in heavy seas.Destroyers of World War Two: An International Encyclopedia. pp. 188/189 Initial problems with stability during high-speed turns were later corrected by widening the beam and bringing up the waterline.

When compared with the Minekaze class, the smaller size necessitated a reduction from four boilers to three and the adoption of lighter-weight Parsons direct-drive turbines, resulting in a drop from 38,500 hp in the Minekaze class to in the Momi class. In addition, fuel capacity was lowered to 275 tons of oil fuel.

As gear turbine technology was not yet perfected, the navy experimented with a variety of power plants on the Momi class:

TurbinesEquipment for Brown-Curtis turbines Kaya, Warabi and Tade Parsons impulse turbines Hishi and Hasu Escher Wyss & Cie Zoelly turbines Sumire Mitsubishi Shipbuilding High-pressure impulse turbine and low-pressure reaction turbine Kaki Kampon turbines all others

The Momi class was heavily armed for its small displacement, with a main battery of Type 3 120 mm 45 caliber naval guns, the same as was used on the Minekaze-class, and a set of double torpedo launchers. Anti-aircraft protection was provided by two 7.7mm machine guns.

Early operational history Due to their shallow draft, the Momi-class destroyers proved to be excellent for operation in coastal waters, and were used along the coast of China to support amphibious landings during the Second Sino-Japanese War.

A number of the Momi-class vessels were lost or disposed during the interwar period. Momi herself was turned over to trials in 1932, while Warabi was run down by the cruiser on 27 August 1927 off Maizuru, Kyoto. Kaya and Nashi were scrapped in 1939.

Also in 1939, Aoi, Fuji, Hagi, Hishi, Kiku, Satsuki, Tade, Tsuta and Yomogi were removed from front line combat service and converted into patrol vessels. In 1940, Ashi, Kaki, Nine, Sumire, and Take were disarmed, and re-rated as training ships.

By the time of the Pacific War, the Momi-class was reaching the end of its service life, and only three (Tsuga, Hasu and Kuri) remained in service as destroyers. An effort was made to upgrade their capabilities by removing the minesweeping gear from the stern and replacing with 36 to 48 depth charges and four depth charge launchers. The amidships Type 3 guns was replaced by two triple Type 96 AA guns from 1942 to 1943, and a Type 13 radar was added. Tsuga was sunk by air attack 15 January 1945. Hasu was surrendered and scrapped at the end of the war. Kuri was surrendered, but sank after striking a mine off Korea on 8 October 1945.

As patrol boats

Beginning in 1939, nine Momi-class vessels were re-classified as patrol boats and converted for escort duty, having one boiler removed (dropping their power to and speed to just . Their torpedo tubes, minesweeping gear, and the amidships Type 3 gun mount were replaced by six Type 96 AA guns, 36 depth charges, and three depth charge throwers. As well, their names were dropped and they were simply numbered.

During 1941–1942, these vessels were modified again, to carry and launch a Toku Daihatsu-class landing craft, by having the aft smokestack removed and the stern modified with a sloping deck to the waterline, as well as providing accommodation for 150 naval infantry troops. All of these vessels except ex-Fuji (as Patrol Boat #36) were sunk during the course of the Pacific War.

List of ships + Construction data Name Kanji Builder Laid down Launched Completed Fate 樅Yokosuka Naval Arsenal, Japan 23 January 1918 10 June 1919 27 December 1919 Decommissioned, 1 April 1932; renamed ; used for trials to 1936 23 December 1918 10 June 1919 28 March 1920Decommissioned, 1 February 1940 and scrapped Kawasaki Shipyards, Kobe, Japan 2 February 1918 26 August 1919 10 December 1919 Kawasaki Shipyards, Kobe, Japan 2 December 1918 26 August 1919 25 December 1919 Decommissioned, 1 February 1940; converted to training ship; scuttled as breakwater at Akita port in 1948 Uraga Dock Company, Japan 27 February 1919 20 October 1919 2 August 1920 Decommissioned, 1 April 1940; converted to training ship; re-converted to auxiliary ship 23 February 1945; scrapped 1948 Ishikawajima Shipyards, Japan 5 March 1919 17 April 1920 20 June 1920 Sunk off Taiwan, 15 January 1945, in air attack; struck 10 March 1945 Kure Naval Arsenal, Japan 5 September 1919 22 December 1919 31 March 1920 Decommissioned, 1 February 1940; converted to training ship, re-converted to auxiliary ship 15 December 1944; scrapped 1948 Kure Naval Arsenal, Japan 5 December 1919 19 March 1920 30 April 1920 Mined off Pusan, 8 October 1945; struck 25 October 1945 Kawasaki Shipyards, Kobe, Japan 20 January 1920 13 October 1920 10 December 1920 Converted to 1 April 1940; sunk at Palau, 30 March 1944 by air attack; struck 10 May 1944 Kawasaki Shipyards, Kobe, Japan 1 April 1920 9 November 1920 10 December 1920 Converted to 1 April 1940; grounded 23 December 1941 at Wake Island; struck 15 January 1942 Uraga Dock Company, Japan 28 February 1920 29 October 1920 20 April 1921 Converted to 1 April 1940; grounded 23 December 1941 at Wake Island; struck 15 January 1942 Fujinagata Shipyards, Japan 6 December 1919 27 November 1920 31 May 1921 Converted to 1 April 1940; surrendered to Netherlands in July 1946 at Surabaya; scrapped 10 August 1946 Ishikawajima Shipyards, Japan 3 May 1920 21 February 1921 25 May 1921 Converted to 1 April 1940; sunk 6 March 1943 in collision with off Kavien; written off 10 January 1945. Uraga Dock Company, Japan 10 November 1920 9 May 1921 23 March 1922 Converted to 1 April 1940; sunk off Borneo, by 24 January 1942; struck 10 April 1942 Uraga Dock Company, Japan 2 March 1921 8 December 1921 31 July 1922 Retired, 12 October 1945; scuttled as breakwater in Fukui, 1946 Fujinagata Shipyards, Japan 12 October 1920 28 September 1921 19 December 1921 Sunk 24 August 1927 in collision with off Cape Miho; struck 15 September 1927 Fujinagata Shipyards, Japan 20 December 1920 15 March 1921 31 July 1922 Converted to 1 April 1940; torpedoed off Yonaguni by 23 April 1943; struck 1 July 1943 Ishikawajima Shipyards, Japan 24 November 1920 14 December 1921 31 March 1923 Decommissioned, 1 February 1940; converted to training ship, re-converted to auxiliary ship 23 February 1945; scrapped 1948 Kawasaki Shipyards, Kobe, Japan 16 October 1920 9 May 1921 30 June 1921 Converted to 1 April 1940; sunk at Lae by air attack 2 September 1942; struck 10 February 1943 Kawasaki Shipyards, Kobe, Japan 15 November 1920 3 September 1921 29 October 1921 Decommissioned, 1 February 1940; converted to training ship, re-converted to auxiliary ship 15 December 1944; modified to Shin'yō suicide motorboat mothership 1945, scrapped 1947 Ishikawajima Shipyards, Japan 26 February 1921 14 March 1922 19 August 1922 Converted to 1 April 1940: torpedoed Bashi Strait by 25 November 1944; struck 10 March 1945

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