HMS Swordfish ( 1916 ) HMS " Swordfish " was an experimental submarine built for the Royal Navy before the First World War to meet the Navy ' s goal of an " overseas " submarine capable of on the surface . Diesel engines of the period were unreliable and not very powerful so steam turbines were proposed instead to meet the RN ' s requirement . " Swordfish " proved to be slower than designed and unstable while surfacing , and consequently she was modified as an anti - submarine patrol vessel in 1917 . She was paid off before the end of the war and sold for scrapping in 1922 . Design . HMS " Swordfish " was developed to meet a requirement of Royal Navy ' s Submarine Committee for a large submarine capable of operating with the fleet at a surfaced speed of 20 knots . Most of the earlier British submarines had been single - hulled vessels built by Vickers and the Navy was interested in evaluating other designs . Captain Roger Keyes , Inspecting Captain of Submarines , had previously served as naval attaché in Italy and had kept abreast of Italian submarine developments , which notably included double - hulled submarines designed by Cesare Laurenti of Fiat - San Giorgio . Three boats of the " S " class were ordered first and Laurenti was invited to submit a design to meet the RN requirement . Fiat - San Giorgio " was wary about using heavy oil [ Diesel ] engines and hesitated to guarantee the success of such engines of the power required . At the same time Laurenti prepared a design with geared steam turbines having a speed of 18 knots on a surface displacement of 856 tons . " His design was modified by Scotts Shipbuilding and Engineering Company , Greenock , to include guns . " Swordfish " kept the same main dimensions as Laurenti ' s original design , but had a greater displacement and less endurance . Description . " Swordfish " had an overall length of , a beam of , and a draught of . She displaced on the surface and submerged . She had a partial double hull , which extended over 75 % of her length . The upper portion of the double hull was controlled free - flooding while the rest was devoted to watertight ' baling flats ' , ballast and fuel tanks . Her hull was divided into eight compartments by seven watertight bulkheads . " Swordfish " s diving depth and time are not known because the records from her sea trials have not survived . Shutting down her boiler , retracting the funnel and sealing the boiler uptake required about a minute and a quarter , which included switching over to the electric motors . In marked contrast to contemporary Vickers designs much attention was paid to safety arrangements , including her extensive subdivision . Indicator and telephone buoys , which could be released from inside the submarine were provided together with external air connections and a charged high - pressure line which could provide air to any manned compartment or the living spaces . Furthermore the main ballast tanks could be blown from either end of the ship . Propulsion . " Swordfish " had two Parsons geared impulse - reaction steam turbine sets , each driving one of the two propeller shafts . The turbines were powered by a single Yarrow - type boiler . They were designed to produce a total of at a working pressure of which used a superheater to increase the working temperature by . She was fitted with two electric motors which had a combined output of . Two battery rooms each had 64 battery cells . It is uncertain if the ship reached her designed speed of 18 knots on the surface , although it seems unlikely given her increased displacement over Laurenti ' s original design . Maximum speed was underwater . Swordfish could carry of fuel oil which her builders estimated gave her an endurance of at a speed of on the surface . On her batteries her submerged endurance was at a speed of . Armament . " Swordfish " had two tubes for torpedoes in her bow . They were stepped vertically and positioned well back from the stem in a notch from the keel to preserve the fine lines of the bow . Two torpedo tubes were positioned on each beam amidships . Each torpedo tube was provided with one reload . Two guns were fitted on the deck in disappearing mounts , one each fore and aft of the conning tower . They were covered by watertight hoods to preserve the streamlining of the submarine . Construction and service . Swordfish was ordered from Scotts Shipbuilding and Engineering Company on 18 August 1913 although she was not laid down until 28 February 1914 . The start of the First World War six months later greatly hindered her completion and she was not launched until 18 March 1916 . HMS " Swordfish " was commissioned on 28 April 1916 , before completion , and renamed HMS " S1 " that same day . She was not completed until 21 July . Captained by Commander Geoffrey Layton , her post - completion trials lasted for five months as she was used to evaluate steam power for submarine use . Much was learned about the operation of steam submarines , which helped the subsequent design of the steam - powered K - class fleet submarines . She proved to be very unstable while surfacing , presumably because she could not pump the water out of her controlled free - flooding spaces quickly enough in the upper part of her double hull . These problems , coupled with the fact that she was too slow to work with the fleet as originally envisioned , meant that she was impossible to make into an effective warship and she was laid up after her trials . In July 1917 " S1 " reverted to her original name and was converted to a surface patrol vessel between 27 June 1917 and 24 January 1918 . Her torpedo tubes and disappearing guns were removed . She was given a forecastle , a bridge and her funnel was fixed in place and extended . She was rearmed with a pair of 12 - pounder ( ) guns and depth charge s , weapons more suitable for her new role as an anti - submarine patrol boat . " Swordfish " joined the 1st Destroyer Flotilla at Portsmouth upon completion of her sea trials , but nothing is known of her subsequent service . " Swordfish " was paid off on 30 October 1918 and stricken from the Navy List by January 1919 . She was sold for scrapping to Pounds , of Portsmouth in July 1922 , but was reported to have been resold to Hayes , of Porthcawl in 1923 .