Arethusa-class cruiser (1913)

The Arethusa-class cruisers were a class of eight oil-fired light cruisers of the Royal Navy all ordered in September 1912, primarily for service in the North Sea. They had three funnels with the middle one somewhat larger in diameter than the others. All served in World War I. They were designed as follow on to the earlier scout cruisers, to operate with destroyers in the North Sea but incorporated improvements on the previous ships. They retained the side protection introduced in the later ships of the previous Town class, but reverted to a mixed main armament that was a feature of earlier ships. The ships of the class underwent modification during the war, receiving an additional pair of 21 in torpedo tubes and an upgraded anti aircraft armament, whilst all but HMS Undaunted were fitted to lay mines and five of the class had the aft pair of 4 inch guns replaced by a single 6 inch gun. They were found to be very cramped internally.

In order to achieve the high speeds designed they were the first British cruisers with all oil propulsion and lightweight destroyer type machinery. The cruisers cost £285,000 each on average.

Ships

 * Arethusa, built by Chatham Dockyard, laid down 28 October 1912, launched 25 October 1913, and completed August 1914. She was sunk by mine off Felixstowe on 11 February 1916.
 * Aurora, built by Devonport Dockyard, laid down 24 October 1912, launched 30 September 1913, and completed September 1914. She took part in the sinking of the German raider Meteor on 9 August 1915, was transferred to the Royal Canadian Navy in November 1920, and for sold for breaking up in August 1927.
 * Galatea, built by William Beardmore and Company, Dalmuir, laid down 9 January 1913, launched 14 May 1914, and completed December 1914. She also took part in the sinking of the German raider Meteor on 9 August 1915, and was sold for breaking up 25 October 1921.
 * Inconstant, built by Beardmore, laid down 3 April 1914, launched 6 July 1914, and completed January 1915. She was sold for breaking up 9 June 1922.
 * Penelope, built by Vickers, Barrow in Furness, laid down 1 February 1913, launched 25 August 1914, and completed December 1914. She was damaged by a torpedo from the German submarine UB-29 on 25 April 1916, but repaired, and was sold for breaking up in October 1924.
 * Phaeton, built by Vickers, laid down 12 March 1913, launched 21 October 1914, and completed February 1915. She fought at the Dardanelles in 1915, and was sold for breaking up 16 January 1923.
 * Royalist, built by Beardmore, laid down 3 June 1913, launched 14 January 1915, and completed March 1915. She was sold for breaking up 24 August 1922.
 * Undaunted, built by Fairfield Shipbuilding and Engineering Company, Govan, laid down 21 December 1912, launched 28 April 1914, and completed August 1914. She took part in the Battle off Texel on 17 October 1914, and was sold for breaking up 9 April 1923.

Galatea, Inconstant, Phaeton and Royalist fought in the battle of Jutland on 31 May 1916.