Editing Torpedo (section)

=== World War II ===
In the [[interwar period|inter-war years]], financial stringency caused nearly all navies to skimp on testing their torpedoes. Only the British and Japanese had fully tested new technologies for torpedoes (in particular the [[Type 93 torpedo|Type 93]], nicknamed ''Long Lance'' postwar by the US official historian [[Samuel E. Morison]])<ref name="Morison, Samuel Eliot 1950 p.195">{{cite book |last=Morison |first=Samuel Eliot |title=History of United States Naval Operations in World War II: Breaking the Bismarcks Barrier |location=New York |year=1950 |pages=195}}</ref><ref>{{cite book |page=195 |last=Morison |first=Samuel Eliot |title=The Two Ocean War: A Short History of the United States Navy in the Second World War |publisher=Little, Brown |year=1963}}</ref> <!--And unless you can find a ''wartime'' record of it being called Long Lance, this ''postwar'' account gives Morison precedence.--> at the start of World War II. Unreliable torpedoes caused many problems for the American submarine force in the early years of the war, primarily in the [[Pacific War|Pacific Theater]]. One possible exception to the pre-war neglect of torpedo development was the {{Convert|45|cm|4=-caliber|adj=mid}}, 1931-premiered Japanese [[Type 91 torpedo]], the sole aerial torpedo (''Koku Gyorai'') developed and brought into service by the Japanese Empire before the war.<ref>{{cite web | url=http://www.navweaps.com/Weapons/WTJAP_WWII.htm| title=Japan Torpedoes of World War II| website=NavWeaps.com| access-date=2009-08-05}}</ref> The Type 91 had an advanced [[PID controller]] and jettisonable, wooden[[Type 91 torpedo#Kyoban stabilizer plates|'' Kyoban'' aerial stabilizing surfaces]] which released upon entering the water, making it a formidable anti-ship weapon; Nazi Germany considered manufacturing it as the ''Luftorpedo LT 850'' [[Yanagi missions|after August 1942]].<ref>{{cite book |page=13 |author=Fumio Aikō |date=July 25, 1985 |title=Koku Gyorai Note |language=ja |publisher=Privately printed book}}</ref>

The Royal Navy's {{Convert|24.5|in|adj=on}} oxygen-enriched air torpedo saw service in the two {{sclass|Nelson|battleship|4}} battleships, although by World War II, the use of enriched oxygen had been discontinued due to safety concerns.<ref name="ReferenceA">'' Washington's Cherry trees, The Evolution of the British 1921-22 Capital Ships'', NJM Campbell, Warship Volume 1, Conway Maritime Press, Greenwich, {{ISBN| 0 85177 132 7}}, pp. 9-10.</ref> In the final phase of the action against {{ship|German battleship|Bismarck||2|up=y}}, {{HMS|Rodney|29|2}} fired a pair of {{Convert|24.5|in|adj=on}} torpedoes from her port-side tube and claimed one hit.<ref>''Reports of Proceedings 1921-1964'', G.G.O. Gatacre, Nautical Press & Publications, Sydney, 1982, {{ISBN|0 949756 02 4}}, pg.140</ref><ref>''On His Majesty's Service, 1940-41'', Joseph H. Wellings, http://www.ibiblio.org/anrs/docs/D/D7/1002wellings_onhismajestysservice.pdf</ref><ref>Ballantyne, p. 142</ref><ref>''Killing the Bismarck'', Iain Ballantyne, Pen & Sword Books, Yorkshire, {{ISBN|978 1 84415 983 3}}, pp. 258–260.</ref> According to [[Ludovic Kennedy]], "if true, [this is] the only instance in history of one battleship torpedoing another".<ref>'' Pursuit: The Sinking of the Bismarck'', Ludovic Kennedy, William Collins, {{ISBN|0 00 211739 8}}</ref> The Royal Navy continued the development of oxygen-enriched air torpedoes with the [[British 21 inch torpedo#21 inch Mark VII|21 in. Mk. VII]] of the 1920s designed for the {{sclass2|County|cruiser|2}}<nowiki/>s although once again these were converted to run on normal air at the start of World War II. Around this time too the Royal Navy were perfecting the Brotherhood burner cycle engine which offered a performance as good as the oxygen-enriched air engine but without the issues arising from the oxygen equipment and which was first used in the extremely successful and long-lived [[British 21 inch torpedo#21 inch Mark VIII|21 in. Mk. VIII]] torpedo of 1925. This torpedo served throughout WWII (with 3,732 being fired by September 1944) and is still in limited service in the 21st century. The improved Mark VIII** was used in two particularly notable incidents: on 6 February 1945, the only intentional wartime sinking of one submarine by another while both were submerged took place when [[HMS Venturer (P68)|HMS ''Venturer'']] [[Action of 9 February 1945|sank the German submarine]] [[German submarine U-864|''U-864'']] with four Mark VIII** torpedoes, and on 2 May 1982 the Royal Navy submarine {{HMS|Conqueror|S48|6}} sank the Argentine cruiser {{ship|ARA|General Belgrano}} with two Mark VIII** torpedoes during the [[Falklands War]].<ref name="Belgrano sinking">{{cite news |last=Brown |first=Colin |title=Sinking the Belgrano: the Pinochet connection |url=https://www.independent.co.uk/news/world/world-history/sinking-the-belgrano-the-pinochet-connection-7609047.html?origin=internalSearch |access-date=2012-05-02 |newspaper=The Independent |date=2012-04-03 |author2=Kim Sengupta |archive-url=https://web.archive.org/web/20150623025157/http://www.independent.co.uk/news/world/world-history/sinking-the-belgrano-the-pinochet-connection-7609047.html?origin=internalSearch |archive-date=23 June 2015 |location=London |url-status=dead }}</ref> This is the only sinking of a surface ship by a nuclear-powered submarine in wartime and the second (of three) sinkings of a surface ship by any submarine since the end of World War II.  The [[List of submarine actions#Post-World War II|other two]] sinkings were of the [[India]]n frigate {{INS|Khukri|F149|6}} and the South Korean corvette [[ROKS Cheonan (PCC-772)|ROKS ''Cheonan'']].
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[[File:Type93torpedo.jpg|thumb|left|A Japanese [[Type 93 torpedo]] – nicknamed "Long Lance" after the war]]
Many classes of surface ships, submarines, and aircraft were armed with torpedoes. Naval strategy at the time was to use torpedoes, launched from submarines or warships, against enemy warships in a fleet action on the high seas.  There were concerns that torpedoes would be ineffective against warships' heavy armor; an answer to this was to detonate torpedoes underneath a ship, badly damaging its [[keel]] and the other structural members in the hull, commonly called "breaking its back". This was demonstrated by [[Naval mine#Influence mines|magnetic influence mine]]s in World War I. The torpedo would be set to run at a depth just beneath the ship, relying on a magnetic exploder to activate at the appropriate time.

Germany, Britain, and the U.S. independently devised ways to do this; German and American torpedoes, however, suffered problems with their depth-keeping mechanisms, coupled with faults in [[magnetic pistol]]s shared by all designs. Inadequate testing had failed to reveal the effect of the Earth's magnetic field on ships and exploder mechanisms, which resulted in premature detonation. The ''[[Kriegsmarine]]'' and Royal Navy promptly identified and eliminated the problems. In the United States Navy (USN), there was an extended wrangle over the problems plaguing the [[Mark 14 torpedo]] (and its [[Mark 6 exploder]]). Cursory trials had allowed bad designs to enter service, and both the Navy [[Bureau of Ordnance]] and the [[United States Congress]] were too busy protecting their interests to correct the errors.  Fully functioning torpedoes only became available to the USN twenty-one months into the Pacific War.<ref>{{Harvard citation no brackets|Blair|1975|p=20}}</ref>

[[File: Vickers wellington VIII torpedo.jpg|thumb|right|Loading [[British 21 inch torpedo#21 inch Mark VIII|21-inch RNTF Mark VIII]] torpedoes into a [[Vickers Wellington]] medium bomber, May 1942. This type of torpedo was used to sink the Argentinian cruiser {{ship|ARA|General Belgrano||2}} during the 1982 [[Falklands War]].]]

British submarines used torpedoes to interdict the Axis supply shipping to [[North Africa]], while [[Fleet Air Arm]] [[Fairey Swordfish|Swordfish]] [[Battle of Taranto|sank three Italian battleships at Taranto]] by a torpedo and (after a mistaken, but abortive, attack on {{HMS|Sheffield|C24|2}}) scored one crucial hit in the hunt for the German battleship {{ship|German battleship|Bismarck||2}}. Large tonnages of merchant shipping were sunk by submarines with torpedoes in both the [[Battle of the Atlantic]] and the Pacific War.

Torpedo boats, such as [[Motor Torpedo Boat|MTBs]], [[PT boat]]s, or [[E-boat|S-boats]], enabled the relatively small but fast craft to carry enough firepower, in theory, to destroy a larger ship, though this rarely occurred in practice. The largest warship sunk by torpedoes from small craft in World War II was the British cruiser {{HMS|Manchester|15|2}}, sunk by Italian [[MAS boat]]s on the night of 12/13 August 1942 during [[Operation Pedestal]]. Destroyers of all navies were also armed with torpedoes to attack larger ships. In the [[Battle off Samar]], destroyer torpedoes from the escorts of the American task force "Taffy 3" showed effectiveness at defeating armor. Damage and confusion caused by torpedo attacks were instrumental {{Original research inline|date=September 2011}} <!--Remove FACT TAG as the statement is cited but not directly supported by citation--> in beating back a superior Japanese force of battleships and cruisers. In the [[Battle of the North Cape]] in December 1943, torpedo hits from British destroyers {{HMS|Savage|G20|2}} and {{HMS|Saumarez|G12|2}} slowed the German battleship {{ship|German battleship|Scharnhorst||2}} enough for the British battleship {{HMS|Duke of York|17|2}} to catch and sink her, and in May 1945 the British 26th Destroyer Flotilla (coincidentally led by ''Saumarez'' again) ambushed and sank Japanese heavy cruiser {{ship|Japanese cruiser|Haguro||2}}.

As a result of the "[[Channel Dash]]" of 1942, when three German warships successfully evaded Royal Navy and Royal Air Force attacks and passed the length of the [[English Channel]] from the Atlantic to the North Sea, Britain's [[Minister of Aircraft Production|Ministry of Aircraft Production]] commissioned the [[Helmover torpedo]], a five-ton air-launched weapon, but it did not enter service until 1945 and saw no action.<ref>{{cite book |last1=McCloskey |first1=Keith |title=Airwork: a history |date=2012 |publisher=The History Press Ltd |location=Stroud, England |isbn=978-0-7524-7972-9 |pages=29–30|url=https://books.google.com/books?id=_607AwAAQBAJ&dq=helmore+torpedo&pg=PT37}}</ref>