The 24 class was a class

Ship class

A ship class is a group of ships of a similar design. This is distinct from a ship-type, which might reflect a similarity of tonnage or intended use. For example, the is a nuclear aircraft carrier of the Nimitz class....

 of minesweeping sloops

Sloop-of-war

In the 18th and most of the 19th centuries, a sloop-of-war was a warship with a single gun deck that carried up to eighteen guns. As the rating system covered all vessels with 20 guns and above, this meant that the term sloop-of-war actually encompassed all the unrated combat vessels including the...

. Derived from the preceding , but designed to appear double-ended. Twenty-four ships to this design (hence the class name) were ordered between December 1916 and April 1917 under the Emergency War Programme for the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 in World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, although two of them were cancelled before launch. All were named after famous racehorses (winners of the Epsom Derby

Epsom Derby

The Derby Stakes, popularly known as The Derby, internationally as the Epsom Derby, and under its present sponsor as the Investec Derby, is a Group 1 flat horse race in Great Britain open to three-year-old thoroughbred colts and fillies...

), but they were not named Racehorse class as the Admiralty

Admiralty

The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...

 realised that this could easily be confused in communications with the of paddle minesweepers, and they officially became the 24 class.

Like the Flower-class sloops, they were single-screw fleet sweeping sloops used almost entirely for minesweeping, although only ten were completed by the Armistice

Armistice

An armistice is a situation in a war where the warring parties agree to stop fighting. It is not necessarily the end of a war, but may be just a cessation of hostilities while an attempt is made to negotiate a lasting peace...

 in 1918. However, they had identical deckhouses and gun shields at either end of the vessel, with straight stems and sterns. Furthermore four of those completed had the single mast aft of the centrally-located funnel, and the rest had the mast forward of the funnel.

Ships

— built by Swan Hunter & Wigham Richardson, Wallsend

Wallsend

Wallsend is an area in North Tyneside, Tyne and Wear, England. Wallsend derives its name as the location of the end of Hadrian's Wall. It has a population of 42,842.-Romans:...

 on Tyne, launched 6 June 1918. Sold 12 August 1920. — built by Barclay Curle & Company, Whiteinch

Whiteinch

Whiteinch is a district in the Scottish city of Glasgow. It is situated north of the River Clyde between the Partick and Scotstoun areas of the city...

, launched 24 September 1918. Sold 12 August 1920. — built by Swan Hunter, launched 26 July 1918. Sold for breaking up 1 December 1921. — built by Greenock & Grangemouth Dockyard Company, launched 27 April 1918. Sold 15 November 1922. — built by Swan Hunter, launched 28 March 1918. Transferred to RNVR on 24 March 1920.

• HMS Galtee More — ordered from Osbourne Graham, transferred to Swan Hunter 7 June 1918, then cancelled 3 December 1918. — built by Barclay Curle & Company, Whiteinch
  Whiteinch
  Whiteinch is a district in the Scottish city of Glasgow. It is situated north of the River Clyde between the Partick and Scotstoun areas of the city...
  
  , launched 2 November 1918. Sold for breaking up in August 1922. — built by Barclay Curle, launched 24 August 1918. Survey ship in 1922. Sold for breaking up 15 January 1923. — built by Greenock & Grangemouth Dockyard, launched 5 March 1919. Sold 12 August 1920. — built by Osbourne Graham & Company, Sunderland, launched 21 September 1918. Sold 6 November 1920. — built by Blyth Shipbuilding & Dry Dock Company, launched 19 December 1918. Survey ship in February 1923, renamed Herald. Scuttled in February 1942 at Selatar
  Seletar
  Seletar is an area of Singapore within its North-East Region. Seletar commonly refers to the areas south of Yishun and west of Sungei Punggol, covering Yio Chu Kang near Jalan Kayu , the Lower Seletar Reservoir and part of Upper Thomson .The Seletar Planning Area, an urban planning zone under the...
  
   but salved by the Japanese Navy and added as IJN Heiyo in October 1942. Sunk by mine 14 November 1944. — built by Swan Hunter, launched 6 June 1919. Sold 25 February 1920, becoming mercantile Haim Mazza. — built by Swan Hunter, launched 22 October 1918. Sold to break up 15 November 1922. — built by Blyth Shipbuilding & Dry Dock Company, launched 8 June 1918. Survey vessel in March 1924. Sold 6 August 1937 to break up. — built by Osbourne Graham, launched 4 March 1919. Sold 12 August 1920 but sale was cancelled; re-sold 13 October 1922. — built by Swan Hunter, launched 10 July 1918. Sold 15 November 1922. — built by Greenock & Grangemouth Dockyard Company, Greenock, launched 10 June 1918. Sold 15 November 1922. — built by Barclay Curle, launched 6 July 1918. Sold August 1922. — built by Barclay Curle, launched 12 April 1918. Transferred to Royal Australian Navy
  Royal Australian Navy
  The Royal Australian Navy is the naval branch of the Australian Defence Force. Following the Federation of Australia in 1901, the ships and resources of the separate colonial navies were integrated into a national force: the Commonwealth Naval Forces...
  
  in December 1924 and became survey ship HMAS Moresby in April 1925. Escort vessel 1940. Sold for breaking up 1946 at Newcastle, NSW. — built by Barclay Curle, launched 11 May 1918. Transferred to RNVR in September 1923, renamed Irwell, then again renamed Eaglet in 1926. — built by Greenock & Grangemouth, launched 20 September 1918. Depot ship in October 1919. Sold for breaking up 25 June 1930. — built by Osbourne Graham, launched 4 December 1918. Sold 12 August 1920, becoming mercantile Fanny Mazza. — built by Swan Hunter, launched 23 September 1918. Sold for breaking up 29 November 1922.
• HMS Sunstar — ordered from Swan Hunter, but cancelled 3 December 1918.