- Design and description
- Construction and career
- Notes
- References
- External links
{{Use dmy dates|date=January 2018}}{{Use British English|date=January 2018}}{{Infobox ship image| Ship image= | Ship caption=
}}{{Infobox ship career | Hide header= | Ship country=United Kingdom | UK|naval}} | Ship name=HMS C21 | Ship ordered= | Ship builder=Vickers, Barrow | Ship laid down=4 February 1908 | Ship launched=26 September 1908 | Ship sponsor= | Ship christened= | Ship completed= | Ship acquired= | Ship commissioned=18 May 1909 | Ship decommissioned= | Ship renamed= | Ship refit= | Ship struck= | Ship reinstated= | Ship homeport= | Ship motto= | Ship nickname= | Ship honours= | Ship fate= Sold, 5 December 1921 | Ship status= | Ship notes=
}}{{Infobox ship characteristics | Hide header= | Header caption= | Ship class=C-class submarine | 290|LT|t|abbr=on}} surfaced- {{convert|320|LT|t|abbr=on}} submerged
| 142|ft|3|in|m|1|abbr=on}} | 13|ft|7|in|m|1|abbr=on}} | 11|ft|6|in|1|abbr=on}} | 600|bhp|kW|lk=in|abbr=on}} petrol- {{convert|300|hp|kW|abbr=on}} electric
| Ship propulsion=*1 × 16-cylinder Vickers petrol engine | 13|kn|abbr=on|lk=in}} surfaced- {{convert|8|kn|abbr=on}} submerged
| 910|nmi|abbr=on|lk=in}} at {{convert|12|kn|abbr=on}} on the surface | 100|ft|1}} | Ship complement=2 officers and 14 ratings | Ship armament=2 × 18 in (450 mm) bow torpedo tubes | Ship notes=
}} | HMS C21 was one of 38 C-class submarines built for the Royal Navy in the first decade of the 20th century. The boat survived the First World War and was sold for scrap in 1921. Design and descriptionThe C-class boats of the 1907–08 and subsequent Naval Programmes were modified to improve their speed, both above and below the surface. The submarine had a length of {{convert|142|ft|3|in|m|1}} overall, a beam of {{convert|13|ft|7|in|m|1}} and a mean draft of {{convert|11|ft|6|in|m|1}}. They displaced {{convert|290|LT|t}} on the surface and {{convert|320|LT|t}} submerged. The C-class submarines had a crew of two officers and fourteen ratings.[1] For surface running, the boats were powered by a single 12-cylinder[2] {{convert|600|bhp|lk=in|0|adj=on}} Vickers petrol engine that drove one propeller shaft. When submerged the propeller was driven by a {{convert|300|hp|0|adj=on}} electric motor.[1] They could reach {{convert|13|kn|lk=in}} on the surface and {{convert|8|kn}} underwater. On the surface, the C class had a range of {{convert|910|nmi|lk=in}} at {{convert|12|kn}}.[3] The boats were armed with two 18-inch (45 cm) torpedo tubes in the bow. They could carry a pair of reload torpedoes, but generally did not as they would have to remove an equal weight of fuel in compensation.[4] Construction and careerC21 was laid down on 4 February 1908 by Vickers at their Barrow-in-Furness shipyard, launched on 26 September and was completed on 18 May 1909. During World War I, the boat was generally used for coastal defence and training in home waters. C21 was sold for scrap on 5 December 1921. Notes1. ^1 Gardiner & Gray, p. 87
2. ^Harrison, Chapter 25
3. ^Harrison, Chapters 3
4. ^Harrison, Chapter 27
References- {{cite book|last=Akermann|first=Paul|title=Encyclopaedia of British Submarines 1901–1955|edition=reprint of the 1989|year=2002|publisher=Periscope Publishing|location=Penzance, Cornwall|isbn=1-904381-05-7}}
- {{Colledge}}
- {{cite book |editor1-last=Gardiner|editor1-first=Robert|editor2-last=Gray|editor2-first=Randal|title=Conway's All the World's Fighting Ships: 1906–1921|year=1984|location=Annapolis, Maryland|publisher=Naval Institute Press|isbn=0-85177-245-5|lastauthoramp=y}}
- {{cite web|url=http://www.rnsubs.co.uk/Boats/BR3043/chapter07.php|title=The Development of HM Submarines From Holland No. 1 (1901) to Porpoise (1930) (BR3043)|last=Harrison|first=A. N.|date=January 1979|publisher=Submariners Association: Barrow in Furness Branch|accessdate=19 August 2015|deadurl=yes|archiveurl=https://web.archive.org/web/20150519040644/http://www.rnsubs.co.uk/Boats/BR3043/chapter07.php|archivedate=19 May 2015|df=}}
External links - MaritimeQuest HMS C21 pages
{{British C class submarine}}{{DEFAULTSORT:C21}} 4 : Ships built in Barrow-in-Furness|British C-class submarines|Royal Navy ship names|1908 ships |