- References
{{Use dmy dates|date=January 2017}}{{Use British English|date=January 2017}}{{no footnotes|date=February 2013}}{{Infobox ship image| Ship image= | Ship caption=
}}{{Infobox ship class overview | Name= | Builders=Armstrong Whitworth | Operators= Royal Navy | Class before= | Class after= | Subclasses= | Cost= | Built=4 | In service range= | In commission range= | Total ships building= | Total ships planned= | Total ships completed=4 | Total ships cancelled= | Total ships active= | Total ships laid up= | Total ships lost= | Total ships retired= | Total ships preserved=
}}{{Infobox ship characteristics | Hide header= | Header caption= | Ship class=British W class | Ship type= | Ship tonnage= | Ship displacement=*W1, W2 331 tons surfaced/499 tons submerged- W3, W4 321 tons surfaced/379 tons submerged
| Ship tons burthen= | Ship length=W1, W2 171' 11"; W3, W4 149' 11" | Ship beam=W1, W2 15' 4"; W3, W4 17' 10" | Ship height= | Ship draught= | Ship draft= | Ship depth= | Ship hold depth= | Ship decks= | Ship deck clearance= | Ship ramps= | Ship ice class= | Ship power= | Ship propulsion=2-shaft diesel, electric motors, 740bhp/ 380shp | Ship sail plan= | 13|kn}} surfaced/ 8 knots submerged | 2500|nmi|km mi|abbr=on}} at {{convert|9|kn}} | Ship endurance= | Ship test depth= | Ship boats= | Ship capacity= | Ship troops= | Ship complement=18 | Ship crew= | Ship time to activate= | Ship sensors= | Ship EW= | Ship armament=2-18in TT (bow) torpedoes, 4-18in torpedoes in external drop collars (removed), 1-3in AA gun | Ship armour= | Ship armor= | Ship aircraft= | Ship aircraft facilities= | Ship notes=
}} | The W class submarines were built for the Royal Navy as experimental boats. They were based on a French Schneider-Laubeuf design. The design for W3 and W4 was heavily modified to meet Royal Navy requirements, overcoming some of the deficiencies of the 'off the shelf' design. In particular, the drop-collars were removed in the later boats. Only four W class submarines were built from 1913 to 1916. The first two boats took 15 and 17 months to build, which at the time was a remarkable feat compared to other building times. The W class had very good performance, with excellent diving control and efficient venting and flooding systems. The class did have problems with habitability, but other than that, they were good submarines. All four of the W class submarine were transferred to the Italian Navy in August 1916, where they retained their numbering. - HMS W1, launched 19 November 1914
- HMS W2, launched 15 February 1915
- HMS W3, launched 1 April 1915
- HMS W4, launched 26 November 1915
References - The Royal Navy Submarine Service, A centennial History, by Antony Preston.
- {{cite book| last = Gardiner| first = Robert|author2= Gray, Randal|author3= Budzbon, Przemysław | year = 1985| title = Conway's All the world's fighting ships, 1906–1921| publisher =Conway| isbn = 0-85177-245-5}}
{{British W class submarines}} 5 : Submarine classes|British W-class submarines|World War I submarines of the United Kingdom|World War I submarines of Italy|Ships built by Armstrong Whitworth |