Editing Submarine (section)

====World War II====
{{See also|List of submarines of World War II}}
[[File:I400 2.jpg|thumb|The [[Imperial Japanese Navy]]'s {{sclass|I-400|submarine|2}}, the largest submarine type of WWII]]
[[File:U-47.jpg|thumb|A model of [[Günther Prien]]'s {{GS|U-47|1938|2}}, German WWII [[Type VII submarine|Type VII]] diesel–electric hunter]]

During [[World War II]], Germany used submarines to devastating effect in the [[Battle of the Atlantic]], where it attempted to cut Britain's supply routes by sinking more [[merchant ship]]s than Britain could replace. These merchant ships were vital to supply Britain's population with food, industry with raw material, and armed forces with fuel and armaments. Although the U-boats had been updated in the interwar years, the major innovation was improved communications, encrypted using the [[Enigma machine|Enigma cipher machine]]. This allowed for mass-attack [[naval tactics]] (''Rudeltaktik'', commonly known as "[[Wolfpack (naval tactic)|wolfpack]]"), which ultimately ceased to be effective when [[Cryptanalysis of the Enigma|the U-boat's Enigma was cracked]]. By the end of the war, almost 3,000 [[Allies of World War II|Allied]] ships (175 warships, 2,825 merchantmen) had been sunk by U-boats.<ref>{{cite book|last=Crocker III|first=H. W.|title=Don't Tread on Me|publisher=Crown Forum|year=2006|location=New York|page=[https://archive.org/details/donttreadonme40000croc/page/310 310]|isbn=978-1-4000-5363-6|url=https://archive.org/details/donttreadonme40000croc/page/310}}</ref><!--not solely by torpedo, I wager...--> Although successful early in the war, Germany's U-boat fleet suffered heavy casualties, losing 793 U-boats and about 28,000 submariners out of 41,000, a casualty rate of about 70%.<ref>{{cite news |title=The Battle of the Atlantic: The U-boat peril |url=https://www.bbc.co.uk/history/worldwars/wwtwo/battle_atlantic_01.shtml |work=BBC |date=30 March 2011}}</ref>

The [[Imperial Japanese Navy]] operated the most varied fleet of submarines of any navy, including ''[[Kaiten]]'' crewed torpedoes, midget submarines ({{sclass2|Type A Ko-hyoteki|submarine|5}} and {{sclass|Kairyu|submarine|4}}es), medium-range submarines, purpose-built supply submarines and long-range [[fleet submarine]]s. They also had submarines with the highest submerged speeds during World War II ({{sclass|I-201|submarine|2}}s) and submarines that could carry multiple aircraft ({{sclass|I-400|submarine|2}}s). They were also equipped with one of the most advanced torpedoes of the conflict, the oxygen-propelled [[Type 95 torpedo|Type 95]]. Nevertheless, despite their technical prowess, Japan chose to use its submarines for fleet warfare, and consequently were relatively unsuccessful, as warships were fast, maneuverable and well-defended compared to merchant ships.

The submarine force was the most effective anti-ship weapon in the American arsenal. Submarines, though only about 2 percent of the U.S. Navy, destroyed over 30 percent of the Japanese Navy, including 8 aircraft carriers, 1 battleship and 11 cruisers. US submarines also destroyed over 60 percent of the Japanese merchant fleet, crippling Japan's ability to supply its military forces and industrial war effort. [[Allied submarines in the Pacific War]] destroyed more Japanese shipping<!--because "shipping" means "merchant", generally, & that's the important factor--> than all other weapons combined. This feat was considerably aided by the Imperial Japanese Navy's failure to provide adequate escort forces for the nation's merchant fleet.

During World War II, 314&nbsp;submarines served in the US Navy, of which nearly 260 were deployed to the Pacific.<ref name="O'Kane, p. 333">O'Kane, p. 333</ref> When the Japanese attacked Hawaii in December 1941, 111 boats were in commission; 203 submarines from the {{sclass|Gato|submarine|5}}, {{sclass|Balao|submarine|5}}, and {{sclass|Tench|submarine|4}}es were commissioned during the war. During the war, 52 US submarines were lost to all causes, with 48 directly due to hostilities.<ref>Blair, Clay, Jr. ''Silent Victory'', pp. 991–92. The others were lost to accidents or, in the case of {{USS|Seawolf|SS-197|2}}, [[friendly fire]].</ref> US submarines sank 1,560&nbsp;enemy vessels,<ref name="O'Kane, p. 333" /> a total tonnage of 5.3&nbsp;million tons (55% of the total sunk).<ref name="Blair, p. 878">Blair, p. 878</ref>

The [[Royal Navy Submarine Service]] was used primarily in the classic Axis [[blockade]]. Its major operating areas were around Norway, in the [[Mediterranean]] (against the Axis supply routes to North Africa), and in the Far East. In that war, British submarines sank 2 million tons of enemy shipping and 57 major warships, the latter including 35 submarines. Among these is the only documented instance of a submarine sinking another submarine while both were submerged. This occurred when {{HMS|Venturer|P68|6}} [[Action of 9 February 1945|engaged]] {{GS|U-864||2}}; the ''Venturer'' crew manually computed a successful firing solution against a three-dimensionally maneuvering target using techniques which became the basis of modern torpedo computer targeting systems. Seventy-four British submarines were lost,<ref>{{cite web |url=http://www.royalnavy.mod.uk/server/show/nav.2558 |title=Submarine History |publisher=The Royal Navy |access-date=18 April 2007 |url-status=dead |archive-url=https://web.archive.org/web/20070220150129/http://www.royalnavy.mod.uk/server/show/nav.2558 |archive-date=20 February 2007}}</ref> <!--something more than speculation on cause is wanted-->the majority, forty-two, in the Mediterranean.