HMS H31

{{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, 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 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 *2 × {{convert|620|hp|0|abbr=on}} electric motors | 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 tubes *8 × 21-inch torpedoes

| notes = }} }} '''HMS ''H31''''' was a British H-class submarine built by Vickers Limited, 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. During the war, she took part in the operation to keep the {{Ship|German battleship|Scharnhorst||2|up=yes}} at Brest, France in December 1941 before the "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 in the Bay of Biscay after leaving port on 19 December and failing to respond on 24 December 1941.<ref>{{cite web |url=https://www.wrecksite.eu/wreck.aspx?16101 |title=HMS H-31 (+1941) |publisher=Wrecksite |access-date=6 May 2023}}</ref>

==Design== Like all post-''H20'' British H-class submarines, ''H31'' had a displacement of {{convert|423|LT|t}} at the surface and {{convert|510|LT|t}} while submerged.<ref name="batcru">{{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}}</ref> It had a total length of {{convert|171|ft|m}},<ref name="Walters2004">{{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–}}</ref> a beam of {{convert|15|ft|4|in}}, and a draught of {{convert|12|m}}.<ref name="Colledge"/> It contained a diesel engines providing a total power of {{convert|480|hp}} and two electric motors each providing {{convert|320|hp}} power.<ref name="Colledge">{{Colledge: Ships RN|year=2006}} Retrieved from [http://www.naval-history.net/WW1NavyBritishShips-Dittmar3WarshipsA.htm#10 Naval-History] on 20 August 2015.</ref> 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}}.<ref>{{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}}</ref>

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.<ref name="batcru"/><ref name="Colledge"/> ''H31'' was fitted with an anti-aircraft gun and four {{convert|21|in|adj=on|0}} torpedo tubes. Its torpedo tubes were fitted to the bow and the submarine was loaded with eight {{convert|21|in|adj=on|0}} torpedoes.<ref name="batcru"/> It is a Holland 602 type submarine but was designed to meet Royal Navy specifications. Its complement was twenty-two crew members.<ref name="batcru"/>

==References== {{reflist}}

==Bibliography== * {{cite book |last1=Hutchinson |first1=Robert |title=Jane's submarines : war beneath the waves from 1776 to the present day |date=2001 |publisher=HarperCollins |location=London |isbn=9780007105588}}

{{Holland 602 type submarine}} {{December 1940 shipwrecks}} {{December 1941 shipwrecks}} {{coord missing|Atlantic Ocean}}

{{DEFAULTSORT:H31}} Category:British H-class submarines Category:Ships built in Barrow-in-Furness Category:1918 ships Category:World War I submarines of the United Kingdom Category:World War II submarines of the United Kingdom Category:Lost submarines of the United Kingdom Category:World War II shipwrecks in the Atlantic Ocean Category:Royal Navy ship names Category:Maritime incidents in December 1940 Category:Maritime incidents in December 1941 Category:Ships sunk by mines