{{short description|Submarine of the Royal Navy (1909)}} {{Use dmy dates|date=January 2018}} {{Use British English|date=January 2018}} {{Infobox ship |section1={{Infobox ship/image |image=William Lionel Wyllie - The submarine H.M.S. C18 on patrol.jpg |image_caption=''C18'' on patrol, painting by William Lionel Wyllie }}

|section2={{Infobox ship/career |hide_header= |country=United Kingdom |flag={{shipboxflag|United Kingdom|naval}} |name=''C18'' |ordered= |awarded= |builder=Royal Dockyard, Chatham |laid_down= 11 March 1907 |launched=10 October 1908 |christened= |acquired= |commissioned= 23 July 1909 |recommissioned= |decommissioned= |in_service= |out_of_service= |renamed= |reclassified= |refit= |captured= |struck= |reinstated= |fate=Sold on 26 May 1921 |homeport= }}

|section3={{Infobox ship/characteristics |hide_header= |header_caption= |class=C-class submarine |displacement=*{{convert|287|LT|t|abbr=on}} surfaced *{{convert|316|LT|t|abbr=on}} submerged |length={{convert|142|ft|3|in|m|1|abbr=on}} |beam={{convert|13|ft|7|in|m|1|abbr=on}} |draught={{convert|11|ft|6|in|1|abbr=on}} |power=*{{convert|600|bhp|kW|lk=in|abbr=on}} petrol *{{convert|300|hp|kW|abbr=on}} electric |propulsion=*1 × 16-cylinder Vickers petrol engine *1 × electric motor |speed=*{{convert|12|kn|abbr=on|lk=in}} surfaced *{{convert|7|kn|abbr=on}} submerged |range={{convert|910|nmi|abbr=on|lk=in}} at {{convert|12|kn|abbr=on}} on the surface |test_depth={{convert|100|ft|1}} |complement=2 officers and 14 ratings |armament=2 × 18 in (450 mm) bow torpedo tubes |notes= }} }} '''HMS ''C18''''' 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 description== The C class was essentially a repeat of the preceding B class, albeit with better performance underwater. 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|287|LT|t}} on the surface and {{convert|316|LT|t}} submerged. The C-class submarines had a crew of two officers and fourteen ratings.<ref name=gg9>Gardiner & Gray, p. 87</ref>

For surface running, the boats were powered by a single 16-cylinder {{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.<ref name=gg9/> They could reach {{convert|12|kn|lk=in}} on the surface and {{convert|7|kn}} underwater. On the surface, the C class had a range of {{convert|910|nmi|lk=in}} at {{convert|12|kn}}.<ref>Harrison, Chapter 3</ref>

The boats were armed with two 18-inch (45&nbsp;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.<ref>Harrison, Chapter 27</ref>

==Construction and career== ''C18'' was laid down on 11 March 1907 at the Royal Dockyard, Chatham, launched on 10 October 1908, and completed on 23 July 1909.<ref>Harrison, Appendix 1, p. App. I.3</ref> During World War I, the boat was generally used for coastal defence and training in home waters. HMS ''C18'' was sold for scrap on 26 May 1921 in Sunderland.

==Notes== {{reflist|30em}}

==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: Ships RN|year=2006}} * {{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=1985|location=Annapolis, Maryland|publisher=Naval Institute Press|isbn=0-85177-245-5|name-list-style=amp}} * {{cite web|url=http://rnsubs.co.uk/dits-bits/br-3043.html|title=The Development of HM Submarines From Holland No. 1 (1901) to Porpoise (1930) (BR3043)|last=Harrison|first=A. N.|date=January 1979|publisher=RN Subs|access-date=27 September 2022}}

== External links == * [http://www.maritimequest.com/warship_directory/great_britain/submarines/pages/c_class/c_18_page_1.htm MaritimeQuest HMS ''C18'' pages]

{{British C class submarine}}

{{DEFAULTSORT:C18}} Category:British C-class submarines Category:Royal Navy ship names Category:1908 ships Category:Ships built in Chatham, Kent