SMS S21 was a V1-class torpedo boat of the Imperial German Navy. The ship was built by Schichau-Werke, at their Elbing shipyard, completing in 1913. S21 served with the German High Seas Fleet during the First World War, and sank following a collision with the cruiser on 21 April 1915. Construction and design The V1-class was a new class of torpedo boat intended to be smaller and more manoeuvrable than the Imperial German Navy's latest torpedo boats, which would be more suitable for working with the fleet. Twelve ships were ordered from AG Vulcan and Germaniawerft under the 1911 construction programme, while in 1912, twelve ships of similar design (S13–S24) were ordered from Schichau-Werke. The reduction in size resulted in the ships' seaworthiness being adversely affected, however, and range being reduced, with the 1911 and 1912 torpedo boats acquiring the disparaging nickname "Admiral Lans' cripples". The Schichau boats were long overall and at the waterline, with a beam of and a draught of . Displacement was normal and deep load. Three coal-fired and one oil-fired water-tube boilers fed steam to two direct-drive steam turbines rated at , giving a design speed of . of coal and of oil were carried, giving a range of at or at . S21s armament consisted of two SK L/30 naval guns in single mounts fore and aft, together with four 50 cm (19.7 in) torpedo tubes with one reload torpedo carried. Up to 18 mines could be carried. The ship had a crew of 3 officers and 71 other ranks. S21, yard number 872, was launched at Schichau's shipyard in Elbing, East Prussia (now Elbląg in Poland) on 11 January 1913 and was commissioned on 20 June 1913. Service In May 1914, S21 was a member of the 14th half-flotilla of the 7th Torpedo boat Flotilla. She remained part of the 14th half-flotilla at the outbreak of the First World War in August 1914. The 7th Torpedo Boat Flotilla supported the Raid on Yarmouth on 3 November 1914 and the Raid on Scarborough, Hartlepool and Whitby on 16 December 1914. On 21 April 1915, S21 was one of three torpedo-boats of the 14th half-flotilla that encountered the light cruisers of IV Scouting Group near the Weser estuary. The torpedo boats attempted to cut through the line of cruisers, passing between and , but S21, the second of the three torpedo boats, failed, and S21