# HMS H31
> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/HMS_H31
> Markdown URL: https://mediated.wiki/source/HMS_H31.md
> Source: https://en.wikipedia.org/wiki/HMS_H31
> Source revision: 1345241827
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)
{{short description|Submarine of the Royal Navy}}
{{Use dmy dates|date=December 2016}}
{{Use British English|date=December 2016}}
{{Infobox ship
|section1={{Infobox ship/image
| image = H31 submarine.jpg
| image_caption = HMS ''H31''
}}
|section2={{Infobox ship/career
| hide_header =
| country = United Kingdom
| flag = {{shipboxflag|United Kingdom|naval}}
| name = HMS ''H31''
| owner =
| namesake =
| ordered =
| builder = [Vickers Limited](/source/Vickers_Limited), [Barrow-in-Furness](/source/Barrow-in-Furness)
| yard_number =
| laid_down = 19 April 1917
| launched = 16 November 1918
| acquired =
| commissioned = 21 February 1919
| decommissioned =
| in_service =
| out_of_service =
| struck =
| reinstated =
| fate = Sunk, between 19 and 24 December 1941
}}
|section3={{Infobox ship/characteristics
| hide_header =
| header_caption =
| class = [H-class](/source/British_H-class_submarine) [submarine](/source/submarine)
| displacement =*{{convert|423|LT|t|0|abbr=on}} surfaced
*{{convert|510|LT|t|0|abbr=on}} submerged
| length = {{convert|171|ft|0|in|m|abbr=on}}
| beam = {{convert|15|ft|4|in|m|abbr=on}}
| draught =
| propulsion =*1 × {{convert|480|hp|0|abbr=on}} [diesel engine](/source/diesel_engine)
*2 × {{convert|620|hp|0|abbr=on}} [electric motor](/source/electric_motor)s
| speed =*{{convert|11.5|kn|lk=in}} surfaced
*{{convert|9|kn}} submerged
| range =*{{convert|2985|nmi|km|abbr=on}} at {{convert|7.5|kn|abbr=on}} surfaced
*{{convert|130|nmi|km|abbr=on}} at {{convert|2|kn|abbr=on}} submerged
| endurance =
| test_depth =
| complement = 22
| sensors =
| EW =
| armament =
*4 × {{convert|21|in|mm|0|abbr=on}} bow [torpedo tube](/source/torpedo_tube)s
*8 × [21-inch torpedoes](/source/British_21-inch_torpedo)
| notes =
}}
}}
'''HMS ''H31''''' was a British [H-class](/source/British_H-class_submarine) [submarine](/source/submarine) built by [Vickers Limited](/source/Vickers_Limited), [Barrow-in-Furness](/source/Barrow-in-Furness). She was laid down on 19 April 1917 and was commissioned on 21 February 1919.
HMS ''H31'' survived until [World War II](/source/World_War_II). During the war, she took part in the operation to keep the {{Ship|German battleship|Scharnhorst||2|up=yes}} at [Brest, France](/source/Brest%2C_France) in December 1941 before the "[Channel Dash](/source/Channel_Dash)" to German homeports in the company of {{Ship|German battleship|Gneisenau||2}} and {{Ship|German cruiser|Prinz Eugen||2}} in February 1942. During the operation, ''H31'' was sunk by unknown causes, but most believe she was struck a [naval mine](/source/naval_mine) in the [Bay of Biscay](/source/Bay_of_Biscay) after leaving port on 19 December and failing to respond on 24 December 1941.[{{cite web |url=https://www.wrecksite.eu/wreck.aspx?16101 |title=HMS H-31 (+1941) |publisher=Wrecksite |access-date=6 May 2023}}]
==Design==
Like all post-''H20'' [British H-class submarine](/source/British_H-class_submarine)s, ''H31'' had a displacement of {{convert|423|LT|t}} at the surface and {{convert|510|LT|t}} while submerged.[{{cite book |last1=Gardiner |first1=Robert |last2=Gray |first2=Robert |title=Conway's All the World's Fighting Ships 1906-1921 |date=1985 |publisher=Conway Maritime Press |location=London |isbn=0-85177-245-5 |page=92}}] It had a total length of {{convert|171|ft|m}},[{{cite book|author=Derek Walters|title=The History of the British 'U' Class Submarine|url=https://books.google.com/books?id=VyeJ9DOXcOAC&pg=PA2|year=2004|publisher=Casemate Publishers|isbn=978-1-84415-131-8|pages=2–}}] a beam of {{convert|15|ft|4|in}}, and a draught of {{convert|12|m}}.[{{Colledge: Ships RN|year=2006}} Retrieved from [http://www.naval-history.net/WW1NavyBritishShips-Dittmar3WarshipsA.htm#10 Naval-History] on 20 August 2015.] The use of its electric motors made the submarine travel at {{convert|11|kn|km/h mph}}. It would normally carry {{convert|16.4|LT|t}} of fuel and had a maximum capacity of {{convert|18|LT|t}}.[{{cite web|url=http://www.gwpda.org/naval/hpatsubs.htm|title=Building History and Technical Details for Canadian CC-Boats and the Original H-CLASS|publisher=Electric Boat Company Holland Patent Submarines|author=J. D. Perkins|year=1999|access-date=20 August 2015}}]
The submarine had a maximum surface speed of {{convert|13|kn|km/h mph}} and a submerged speed of {{convert|10.5|kn|km/h mph}}. Post-''H20'' British H-class submarines had ranges of {{convert|2985|nmi|km mi}} at speeds of {{convert|7.5|kn|km/h mph}} when surfaced.