Acasta-class destroyer

The Acasta class (in September 1913 re-designated the K class) was a class of twenty destroyers built for the Royal Navy under the Naval Programme of 1911 - 1912 that saw service during World War I. They were the last class of Royal Navy destroyers to have mixed names with no systematic theme (see naming conventions for destroyers of the Royal Navy for more information.) When the class was designated as "K", names beginning with that letter were allocated to the ships but never used. The class saw extensive wartime service and seven were lost, including four at the Battle of Jutland.

Design
The Acastas were larger and heavier armed than the preceding H and I classes (Acorn-class destroyer and Acheron-class destroyer, respectively), displacing about 25% more and with the mixed calibre armament replaced with a uniform fit of QF 4-inch guns, which the Acastas introduced. Previous 4 in weapons had been of the breech-loading (BL) type. The 4-in guns were shipped one on the forecastle and one at the stern, as in the Acheron class, while the third was variously sited on the centreline between the two torpedo tubes or abaft both. All ships had three funnels, the foremost being tall and narrow, the second short and wide and the third level with the second but narrower. The foremost torpedo tube was sited between the second and third funnels, a distinctive feature of this class.

There were twelve 'standard' vessels built to a common Admiralty design, and eight builders' specials that (except for Garland) had a shorter, less beamy hull; five of the latter were from Thornycroft with 22500 shp (one of Thornycroft's ships, HMS Hardy (1912), was planned to diesel cruising motors, but these were not ready in time and Hardy was completed with Thornycroft's standard machinery). One by Parsons (HMS Garland (1913)) had semi-geared turbines giving a speed of 31 kn on trials, with a seventh from Fairfields had a clipper bow. The eighth 'special' was HMS Ardent (1913) by William Denny, Dumbarton, which was built using longitudinal framing rather than conventional transverse framing. While Ardent novel construction seems to have been a success, no more destroyers were built for the Royal Navy using longitudinal framing until the J-class destroyers in the 1930s.

Service
At the outbreak of World War I until mid-1916, the Acastas were serving in the Grand Fleet as the 4th Destroyer Flotilla, with HMS Swift (1907) as leader. By the time of the Battle of Jutland the leader was the Faulknor-class flotilla leader HMS Tipperary (1914), with Ardent, Fortune, Shark and Sparrowhawk lost in the course of the battle and Acasta was so badly damaged that she had to be practically rebuilt. After Jutland the remainder of the flotilla moved to the Humber and then to Portsmouth by the end of 1916, before dispersing, some ships to the 6th Destroyer Flotilla and the Dover Patrol and the remainder to Devonport. All survivors of the war were sold out of service for scrapping by 1921.