For the class of ships sometimes known as the "Racehorse" class see 24 class sloop

24 class sloop

The 24 class was a class of minesweeping sloops. Derived from the preceding , but designed to appear double-ended. Twenty-four ships to this design were ordered between December 1916 and April 1917 under the Emergency War Programme for the Royal Navy in World War I, although two of them were...

The Racecourse class minesweepers were 32 ships delivered to 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...

 during the First World War. They were built to two related designs as paddlewheel coastal minesweeping sloops under the Emergency War Programme. The vessels were reasonable sea-boats, but lost speed badly in a seaway when the paddle boxes tended to become choked with water. The class is also widely referred to as the Ascot class and Improved Ascot class.

Initial design

The original design was by the Ailsa Shipbuilding Company

Ailsa Shipbuilding Company

-History:The company was founded in 1885 by the 3rd Marquess of Ailsa.In 1902 the Ailsa yard fitted out the polar exploration ship Scotia for the Scottish National Antarctic Expedition of 1902-04...

. The ships were completed between April and October 1916. Launch dates are shown below. — January 1916, Ailsa S.B. Co - first of class, also last ship to be lost in World War I. — January 1916, Ailsa S.B. Co — April 1916, Ailsa S.B. Co — June 1916, Ardrossan Co — April 1916, Ayrshire D.Y. Co — April 1916, Ayrshire D.Y. Co — June 1916 Ayrshire D.Y. Co — September 1916, Ayrshire D.Y. Co — May 1916, G. Brown — February 1916, Clyde S.B. Co. Originally fitted to carry seaplanes. — April 1916, Dundee S.B. Co. — June 1916, Dundee S.B. Co. — March 1916, Dunlop, Bremner

Dunlop Bremner & Company

Dunlop, Bremner & Company was a shipyard at Port Glasgow on the River Clyde, in Scotland, which was purchased by Lithgows in 1919 but continued to trade under its own name until 1926....

 — May 1916, Dunlop, Bremner — Ferguson Bros.

Ferguson Shipbuilders

Ferguson Shipbuilders Limited is a shipyard located in Port Glasgow on the River Clyde in Scotland. It is the last remaining shipbuilder on the lower Clyde, and is currently the only builder of merchant ships on the river - the company's mainstay has long been Roll-on/roll-off ferries.-History:The...

 Lost in World War I. — April 1916, Fleming & Ferguson

Fleming & Ferguson

Fleming and Ferguson was a Scottish marine engineering and shipbuilding company that traded between 1877 and 1969.-1877–1914:W.Y. Fleming and P. Ferguson founded the company in Paisley, Scotland in 1877, making marine steam engines. In 1885 they expanded into shipbuilding by taking over the...

 — Goole Co. - Lost in World War I. — March 1916, Hamilton. Originally fitted to carry seaplanes. — July 1916, A. & J. Inglis — McMillan - Lost in World War I. — June 1916, Murdoch & Murray — Ayrshire D.Y. Co. - Lost in World War I. — July 1916, Dunlop, Bremner — May 1916, McMillan

On this type the foremast is stepped before the fore bridges and they have derricks abeam of the second funnel.

Improved Racecourse type

These paddle minesweepers were designed by 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...

, adapted from the Ailsa Company design for the first type. They were completed between January and June 1918. All were built under the Emergency War Programme.
— December 1917, Ailsa S.B. Co. — February 1918, Ailsa S.B. Co. — December 1917, Clyde S.B. Co. — December 1917, Fleming & Ferguson — March 1918, Fleming & Ferguson — January 1918, Dunlop, Bremner — Dunlop, Bremner. Sold as a ferry boat, 1919. — March 1918, Murdoch & Murray.

The foremast on this type is stepped through the chart house, there are two high ventilators abaft fore funnel and no derricks abeam of the second funnel.