British G-class submarine

The Royal Navy's G-class of diesel/electric submarines were launched between 1914 and 1917, and intended for operations in the North Sea and German Bight in World War I against German U-boats. The design was based on the E-class, adopting the double hull concept, but in practice showed little improvement, the ships notoriously slow to dive.

A total of 14 boats were built at four yards: G1 to G5 by Chatham Dockyard, G6 & G7 by Armstrong Whitworth, G8 to G13 by Vickers, and G14 by Scott's on the Clyde. G15 was ordered from Samuel White's yard at Cowes, Isle of Wight, but cancelled. The class was distinguished by the 21-inch stern torpedo tube, an electric oven in the galley, and Fessenden Underwater Sound Telegraphy. The G-class had their bows raised during the war to increase buoyancy and improve seakeeping.

Boats
Fourteen of fifteen vessels ordered were completed:
 * G1 - Launched 14 August 1915. Sold for scrap 1920.
 * G2 - Launched 23 December 1915. Sank U-78 in the Skagerrak, 28 October 1918. Sold for scrap 1920.
 * G3 - Launched 22 January 1916. Sold for scrap 1920.
 * G4 - Launched 23 October 1915. Sold 1928.
 * G5 - Launched 23 November 1915. Sold 1922.
 * G6 - Launched 7 December 1915. Sold 1921.
 * G7 - Launched 14 March 1916. Last British submarine lost in  World War I, on or about 23 October 1918, cause unknown.
 * G8 - Launched 1 May 1916. Lost in the North Sea for reasons unknown on or about 14 January 1918.
 * G9 - Launched 15 June 1916. Sunk in error by HMS Pasley on 16 September 1917. One survivor.
 * G10 - Launched 11 January 1916. Sold 1923.
 * G11 - Launched 22 February 1916. Wrecked on rocks off Howick, Northumberland, in thick fog, 22 November 1918. Two crew drowned while abandoning ship.
 * G12 - Launched 24 March 1916. Sold 1920.
 * G13 - Launched 18 July 1916. Sank UC-43 off Muckle Flugga, 10 March 1917. Sold 1923.
 * G14 - Launched 17 May 1917. Sold 1923.
 * G15 - Ordered 30 September 1914, cancelled 20 April 1915