View source for Torpedo

{{short description|Self-propelled underwater weapon}}
{{See also|Anti-submarine missile}}
{{about|the self-propelled weapon|the pre-1900 naval meaning of "torpedo"|Naval mine|other uses}}
[[File:Mark 8 torpedo in Germanton Park.jpg|thumb|upright=1.5|[[Bliss–Leavitt Mark 8 torpedo]]]]

A '''torpedo''' is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, with an explosive [[warhead]] designed to detonate either on contact with or in proximity to the target. Historically, such a device was called an automotive, automobile, locomotive, or fish torpedo; colloquially, a ''fish''.

The term ''torpedo'' originally applied to a variety of devices, most of which would today be called [[Naval mine|mines]]. From about 1900, ''torpedo'' has been used strictly to designate a self-propelled underwater explosive device.

While the 19th-century [[battleship]] had evolved primarily with a view to engagements between armored warships with [[naval artillery|large-caliber guns]], the invention and refinement of torpedoes from the 1860s onwards allowed small [[torpedo boat]]s and other lighter [[surface combatant|surface vessel]]s, [[submarine]]s/[[submersible]]s, even improvised [[fishing boat]]s or [[frogmen]], and later [[light aircraft]], to destroy large ships without the need of large guns, though sometimes at the risk of being hit by longer-range artillery fire.

Modern torpedoes are classified variously as lightweight, heavyweight, straight-running, autonomous homers, and wire-guided types.  They can be launched from a variety of platforms. In modern warfare, a submarine-launched torpedo is almost certain to hit its target; the best defense is a counterattack using another torpedo.<ref>{{cite magazine |url=https://www.popularmechanics.com/military/weapons/a41926547/why-torpedoes-are-tough-to-defend-against/ |title=Why One of the Slowest Weapons in Modern Warfare Is the Toughest to Defend Against |last=Mizokami |first=Kyle |date=November 16, 2022 |magazine=[[Popular Mechanics]] |access-date=February 11, 2023}}</ref><ref>{{cite web |url=https://www.thedrive.com/the-war-zone/33018/modern-submarine-torpedo-attacks-are-nothing-like-what-you-see-in-the-movies |title=Modern Submarine Torpedo Attacks Are Nothing Like What You See In The Movies |date=April 16, 2020 |last=Amick |first=Aaron |work=The Drive |access-date=February 11, 2023}}</ref>

==Etymology==

The word ''torpedo'' was first used as a name for [[torpedo fish|electric rays]] (in the order ''[[Torpediniformes]]''), which in turn comes from the Latin word ''[[wikt:torpedo#Latin|torpēdō]]'' ("lethargy" or "sluggishness").<ref>{{cite web |title=torpedo (n.) |url=https://www.etymonline.com/word/torpedo |website=Online Etymology Dictionary |publisher=Douglas Harper |access-date=28 March 2024}}</ref> In naval usage, the American inventor [[David Bushnell (inventor)|David Bushnell]] was reported to have first used the term as the name of a submarine of his own design, the "American Turtle or Torpedo." This usage likely inspired [[Robert Fulton]]'s use of the term to describe his stationary [[Naval mine|mines]], and later [[Robert Whitehead (engineer)|Robert Whitehead]]'s naming of the first self-propelled torpedo.<ref>{{cite web |title=torpedo |url=https://www.merriam-webster.com/dictionary/torpedo#:~:text=Like%20the%20adjective%20torpid%2C%20torpedo,fish%20that%20torpedo%20first%20entered |website=Merriam-Webster Dictionary | date=19 March 2024 |publisher=Merriam-Webster |access-date=28 March 2024}}</ref><ref>{{cite web |title=Navy's Use of Torpedoes |url=https://www.history.navy.mil/browse-by-topic/exploration-and-innovation/navy-torpedoes.html |website=Naval History and Heritage Command |publisher=U.S. Navy |access-date=28 March 2024}}</ref><ref>{{cite web |title=HISTORY OF EARLY TORPEDOES (1800-1870) |url=https://maritime.org/doc/jolie/part1.php |publisher=San Francisco Maritime National Park Association |access-date=28 March 2024}}</ref>

==History==
=== Middle Ages ===
Torpedo-like weapons were proposed many centuries before they were successfully developed. For example, in 1275, engineer [[Hasan al-Rammah]] – who worked as a military scientist for the [[Mamluk Sultanate (Cairo)|Mamluk Sultanate]] of Egypt – wrote that it might be possible to create a projectile resembling an egg, which propelled itself through water carrying fire".<ref>{{citation | first= James Riddick  | last= Partington | author-link = J. R. Partington | title=A History of Greek Fire and Gunpowder | publisher=Johns Hopkins University Press |location=Baltimore, Maryland | year=1999 | page=203 | isbn=0-8018-5954-9 | url=https://books.google.com/books?id=30IJLnwpc8EC}}</ref>

===Early naval mines===
{{Main|Naval mine}}
[[File:Fulton's torpedo.jpg|thumb|right|Fulton's torpedo<ref name=Lossing/>{{rp|238}}]]
[[File: Sinking torpedoes by moonlight in Charleston Harbor - Harper's Weekly, June 13, 1863.jpg|thumb|right|Confederates laying naval mines in Charleston Harbor]]

In modern language, a "torpedo" is an underwater self-propelled explosive, but historically, the term also applied to primitive naval mines and [[spar torpedoes]]. These were used on an ad-hoc basis during the early modern period up to the late 19th century.

In the early 17th century, the Dutchman [[Cornelius Drebbel]], in the employ of [[King James I of England]], invented the spar torpedo; he attached explosives to the end of a beam affixed to one of his submarines. These were used (to little effect) during the English [[Siege of La Rochelle|expeditions to La Rochelle]] in 1626.<ref name="gray">{{Harvard citation no brackets|Gray|2004}}</ref> The first use of a torpedo by a submarine was in 1775, by the American {{ship||Turtle|submersible|2}}, which attempted to lay a bomb with a [[timed fuse]] on the [[Hull (ship)|hull]] of {{HMS|Eagle|1774|6}} during the [[American Revolutionary War]], but failed in the attempt.

In the early 1800s, the American inventor [[Robert Fulton]], while in France, "conceived the idea of destroying ships by introducing floating mines under their bottoms in submarine boats".<!--Is that quote in Lossing?-->  He employed the term "torpedo" for the explosive charges with which he outfitted his submarine ''[[Nautilus (1800 submarine)|Nautilus]]''. However, both the French and the Dutch governments were uninterested in the submarine.  Fulton then concentrated on developing the torpedo-like weapon independent of a submarine deployment, and in 1804 succeeded in convincing the British government to employ his "catamaran" against the French.<ref name="davey">{{Harvard citation no brackets|Davey|2016}}</ref> An April 1804 torpedo attack on French ships anchored at [[Boulogne-sur-Mer|Boulogne]], and a [[Raid on Boulogne|follow-up attack in October]], produced several explosions but no significant damage, and the weapon was abandoned.

Fulton carried out a demonstration for the US government on 20 July 1807, destroying a vessel in [[New York Harbor|New York's harbor]].  Further development languished as Fulton focused on his "steam-boat matters". After the [[War of 1812]] broke out, the [[Royal Navy]] established a blockade of the [[East Coast of the United States]]. During the war, American forces unsuccessfully attempted to destroy the British [[Ship of the line|ship-of-the-line]] [[HMS Ramillies (1785)|HMS ''Ramillies'']] while it was lying at anchor in [[New London, Connecticut]]'s harbor with torpedoes launched from small boats. This prompted the captain of ''Ramillies'', [[Sir Thomas Hardy, 1st Baronet]], to warn the Americans to cease using this "cruel and unheard-of warfare" or he would "order every house near the shore to be destroyed". The fact that Hardy had been previously so lenient and considerate to the Americans led them to abandon such attempts with immediate effect.<ref name=Lossing>{{Cite book |last=Lossing |first=Benson |title=The Pictorial Field-Book of the War of 1812 |publisher=Harper & Brothers, Publishers |location=New York |year=1868 |pages=240–243, 693 |oclc=886707577}}</ref>

Torpedoes were used by the [[Russian Empire]] during the [[Crimean War]] in 1855 against British warships in the [[Gulf of Finland]]. They used an early form of chemical detonator. During the [[American Civil War]], the term ''torpedo'' was used for what is today called a [[Naval mine#Contact mines|contact mine]], floating on or below the water surface using an air-filled [[Carboy|demijohn]] or similar flotation device. These devices were very primitive and apt to prematurely explode. They would be detonated on contact with the ship or after a set time, although electrical detonators were also occasionally used.  In 1862, the {{USS|Cairo}} became the first warship to be sunk by an electrically-detonated mine. Spar torpedoes were also used; an explosive device was mounted at the end of a spar up to {{convert|30|ft|m|-1|order=flip}} long projecting forward underwater from the bow of the attacking vessel, which would then ram the opponent with the explosives. These were used by the [[Confederate States Navy|Confederate]] submarine {{ship||H. L. Hunley|submarine|2}} to sink the {{USS|Housatonic|1861|6}}, although the weapon was apt to cause as much harm to its user as to its target. [[Rear Admiral]] [[David Farragut]]'s famous/apocryphal command during the [[Battle of Mobile Bay]] in 1864, "[[Damn the torpedoes, full speed ahead!]]", refers to a minefield laid at [[Mobile, Alabama]].

[[File:Romanian spar torpedo boat Rândunica.jpg|thumb|right|NMS ''Rândunica'']]

On 26 May 1877, during the [[Romanian War of Independence]], the Romanian spar torpedo boat {{ship|NMS|Rândunica||2}} attacked and sank the Ottoman [[river monitor]] ''Seyfi''.<ref>{{cite book |first=Cristian |last=Crăciunoiu |title=Romanian navy torpedo boats |url=https://books.google.com/books?id=VilMAQAAIAAJ |year=2003 |publisher=Modelism |isbn=978-973-8101-17-3 |page=19}}</ref> This was the first instance in history when a torpedo boat sank its targets without also sinking.<ref>{{cite book|author=Lawrence Sondhaus|title=Navies of Europe|url=https://books.google.com/books?id=elbJAwAAQBAJ&pg=PA88|date=11 June 2014|publisher=Routledge|isbn=978-1-317-86978-8|pages=88–}}</ref>

===Invention of the modern torpedo===
[[File:Whitehead torpedo General Profile, The Whitehead Torpedo U.S.N.1898.jpg|thumb|upright=2|right|Whitehead torpedo's general profile:
{{div col|colwidth=10em}}
{{unbulleted list
|'''A'''. war-head
|'''B'''. air-flask. 
|'''B{{`}}'''. immersion chamber 
|'''C{{`}}'''. after-body 
|'''C'''. engine room 
|'''D'''. drain holes 
|'''E'''. shaft tube 
|'''F'''. steering-engine 
|'''G'''. bevel gear box 
|'''H'''. depth index 
|'''I'''. tail 
|'''K'''. charging and stop-valves 
|'''L'''. locking-gear 
|'''M'''. engine bed-plate 
|'''P'''. primer case 
|'''R'''. rudder 
|'''S'''. steering-rod tube 
|'''T'''. guide stud 
|'''U'''. propellers 
|'''V'''. valve-group 
|'''W'''. war nose{{refn|The war nose consisted of a detonator, fuse, and protection mechanism which armed the fuse after the torpedo had traveled a short distance.}} 
|'''Z'''. strengthening band}}{{div col end}}]]

A prototype of the self-propelled torpedo was created on a commission placed by [[Giovanni Luppis]], an [[Austro-Hungarian Navy|Austro-Hungarian naval officer]] from [[Rijeka]] (modern-day [[Croatia]]), at the time a port city of the [[Austro-Hungarian Monarchy]] and [[Robert Whitehead (engineer)|Robert Whitehead]], an English engineer who was the manager of a town factory, ''Stabilimento Tecnico di Fiume'' (STF). In 1864, Luppis presented Whitehead with the plans of the ''[[Salvacoste]]'' ("Coastsaver"), a floating weapon driven by ropes from the land that had been dismissed by the naval authorities due to the impractical steering and propulsion mechanisms.

In 1866, Whitehead invented the first effective self-propelled torpedo, the eponymous [[Whitehead torpedo]], the first modern torpedo. French and German inventions followed closely, and the term ''torpedo'' came to describe self-propelled projectiles that traveled under or on water. By 1900, the term no longer included mines and booby-traps, as the navies of the world added submarines, [[torpedo boat]]s, and [[destroyer|torpedo boat destroyer]]s to their fleets.<ref>{{Harvard citation no brackets|Gray|1975}}</ref><ref>{{Harvard citation no brackets|Epstein|2014}}</ref>

Whitehead was unable to improve the machine substantially, since the clockwork motor, attached ropes, and surface attack mode all contributed to a slow and cumbersome weapon. However, he kept considering the problem after the contract had finished, and eventually developed a tubular device, designed to run underwater on its own, and powered by compressed air. The result was a submarine weapon, the ''Minenschiff'' (mine ship), the first modern self-propelled torpedo, officially presented to the Austrian Imperial Naval commission on 21 December 1866.

The first trials were not successful, as the weapon was unable to maintain a course at a steady depth. After much work, Whitehead introduced his "secret" in 1868 which overcame this. It was a mechanism consisting of a [[Pendulum-and-hydrostat control|hydrostatic valve and pendulum]] that caused the torpedo's hydroplanes to be adjusted to maintain a preset depth.

===Production and spread===
[[File: Robert Whitehead with battered test torpedo Fiume c1875.jpg|thumb|right|[[Robert Whitehead (engineer)|Robert Whitehead]] (right) invented the modern torpedo in 1866. Pictured examining a battered test torpedo in [[Rijeka]] c. 1875.]]

The Austrian government decided to invest in the invention, and the factory in Rijeka started producing more Whitehead torpedoes. In 1870, he improved the devices to travel up to approximately {{convert|1000|yards|m|order=flip|sigfig=1}} at a speed of up to {{convert|6|knot|km/h|lk=in}}. [[Royal Navy]] (RN) representatives visited Rijeka for a demonstration in late 1869, and in 1870 a batch of torpedoes was ordered. In 1871, the British Admiralty paid Whitehead [[Pound sterling|£]]15,000 for certain of his developments, and production started at the Royal Laboratories in [[Woolwich]] the following year.

The company in Fiume went bankrupt in 1873, but was reformed as [[Whitehead Torpedo Works]] a few years later, and by 1881 it was exporting torpedoes to ten other countries. The torpedo was powered by compressed air and had an explosive charge of [[gun-cotton]].<ref>{{cite web |url=http://www.maritime.org/doc/whitehead3/pg13.htm |title=The Whitehead Torpedo, notes on handling etc., U.S.N. |website=maritime.org |year=1890 |access-date=10 December 2018}}</ref> Whitehead went on to develop more efficient devices, demonstrating torpedoes capable of {{convert|18|knots|km/h}} in 1876, {{convert|24|knots|km/h}} in 1886, and, finally, {{convert|30|knots|km/h}} in 1890.

In the 1880s, a British committee, informed by hydrodynamicist Dr. [[Robert Edmund Froude|R. E. Froude]], conducted comparative tests and determined that a blunt nose, contrary to prior assumptions, did not hinder speed: in fact, the blunt nose provided a speed advantage of approximately one knot compared to the traditional pointed-nose design. This discovery allowed for larger explosive payloads and increased air storage for propulsion without compromising speed.<ref>{{Cite web |title=A Brief History of U.S. Navy Torpedo Development - Part 1 |url=https://www.maritime.org/doc/jolie/part1.php#page011 |access-date=2024-07-12 |website=www.maritime.org}}</ref>

[[File:Ottoman submarine Abdulhamid 1886.jpg|thumb|left|The [[Thorsten Nordenfelt|Nordenfelt]]-class [[Ottoman Empire|Ottoman]] submarine [[Ottoman submarine Abdül Hamid|''Abdülhamid'']] (1886) was the first submarine in history to fire a torpedo while submerged.]]
Whitehead opened a new factory adjacent to [[Portland Harbour]], England, in 1890, which continued making torpedoes until the end of [[World War II]]. Because orders from the RN were not as large as expected, torpedoes were mostly exported. A series of devices was produced at Rijeka, with diameters from {{convert|14|in|cm|abbr=on|order=flip}} upward. The largest Whitehead torpedo was {{convert|18|in|cm|0|abbr=on|order=flip}} in diameter and {{convert|19|ft|m|abbr=on|order=flip}} long, made of polished steel or [[phosphor bronze]], with a {{convert|200|lb|kg|adj=on|order=flip|sigfig=1}} gun-cotton warhead. It was propelled by a three-cylinder [[Peter Brotherhood#Peter Brotherhood|Brotherhood]] radial engine, using compressed air at around {{convert|1300|psi|MPa|abbr=on|lk=on|order=flip}} and driving two [[contra-rotating]] propellers, and was designed to self-regulate its course and depth as far as possible. By 1881, nearly 1,500 torpedoes had been produced. Whitehead also opened a factory at [[St Tropez]] in 1890 that exported torpedoes to Brazil, the Netherlands, Turkey, and Greece.

Whitehead purchased rights to the [[gyroscope]] of [[Ludwig Obry]] in 1888, but it was not sufficiently accurate, so in 1890 he purchased a better design to improve control of his designs, which came to be called the "Devil's Device". The firm of [[Schwartzkopff torpedo|L. Schwartzkopff]] in Germany also produced torpedoes and exported them to Russia, Japan, and Spain. In 1885, Britain ordered a batch of 50 as torpedo production at home and Rijeka could not meet demand.

In 1893, Royal Navy torpedo production was transferred to the [[Royal Gun Factory]]. The British later established a [[Torpedo Experimental Establishment]] at {{HMS|Vernon|shore establishment|6}} and a production facility at the Royal Naval Torpedo Factory, [[Greenock]], in 1910. These are now closed.

By World War I, Whitehead's torpedo remained a worldwide success, and his company was able to maintain a monopoly on torpedo production. By that point, his torpedo had grown to a diameter of {{cvt|18|in|cm|order=flip}} with a maximum speed of {{convert|30.5|kn|kph}} with a warhead weighing {{convert|170|lb|kg|order=flip}}.

Whitehead faced competition from the American [[Lieutenant Commander]] [[John Adams Howell|John A. Howell]], whose [[Howell torpedo|design]], driven by a [[flywheel]], was simpler and cheaper. It was produced from 1885 to 1895, and it ran straight, leaving no wake. A Torpedo Test Station was set up in [[Rhode Island]] in 1870. The Howell torpedo was the only [[United States Navy]] model until an American company, [[E. W. Bliss Company|Bliss and Williams]], secured manufacturing rights to produce Whitehead torpedoes. These were put into service for the U.S. Navy in 1892. Five varieties were produced, all {{cvt|18|in|cm|order=flip}} in diameter.<ref>{{cite web|url=http://navalunderseamuseum.org/media/6c06204b6731dd48ffff8336ffffe906.pdf|archive-url=https://web.archive.org/web/20130512032155/http://navalunderseamuseum.org/media/6c06204b6731dd48ffff8336ffffe906.pdf|url-status=dead|archive-date=12 May 2013|title=Artifact Spotlight: Whitehead torpedo |website=navalunderseamuseum.org |access-date=18 December 2012}}</ref>

The Royal Navy introduced the Brotherhood wet heater engine in 1907 with the [[British 18-inch torpedo#Mark VII and VII*|{{cvt|18|in|cm|order=flip}} Mk. VII & VII*]], which greatly increased the speed and range over compressed-air engines, and wet heater type engines became the standard in many major navies up to and during the Second World War.

[[File: The first modern-day torpedo launching station in Rijeka, 2020.jpg|thumb|The first modern-day torpedo launching station in Rijeka, 2020]]

===Torpedo boats and guidance systems===
[[File: HMS Lightning - Torpedo Boat 1877.jpg|right|thumb|{{HMS|Lightning|1876|6}}, built in 1877 as a small attack boat armed with torpedoes.]]

[[Ship of the line|Ships of the line]] were superseded by [[ironclad warship|ironclads]], large steam-powered ships with heavy gun armament and heavy armor, in the mid-19th century. Ultimately this line of development led to the [[dreadnought]] category of all-big-gun battleships, starting with {{HMS|Dreadnought|1906|6}}.

Although these ships were incredibly powerful, the new weight of armor slowed them down, and the huge guns needed to penetrate that armor fired at very slow rates. The development of torpedoes allowed for the possibility that small and fast vessels could credibly threaten if not sink even the most powerful battleships. While such attacks would carry enormous risks to the attacking boats and their crews (which would likely need to expose themselves to artillery fire which their small vessels were not designed to withstand), this was offset by the ability to construct large numbers of small vessels far more quickly and for a much lower unit cost compared to a capital ship.

The first boat designed to fire the self-propelled [[#Self-propelled torpedoes|Whitehead torpedo]] was {{HMS|Lightning|1876|6}}, completed in 1877. The [[French Navy]] followed suit in 1878 with {{ship|French torpedo boat|Torpilleur No 1||2}}, launched in 1878, though she had been ordered in 1875. The first torpedo boats were built at the shipyards of Sir [[John Isaac Thornycroft|John Thornycroft]] and gained recognition for their effectiveness.

At the same time, inventors were working on building a guided torpedo. Prototypes were built by [[John Ericsson]], [[John Louis Lay]], and Victor von Scheliha, but the first practical guided missile was patented by [[Louis Brennan]], an emigre to Australia, in 1877.<ref name=gray/>

[[File: Brennan torpedo launching.jpg|thumb|left|The [[Brennan torpedo]] was the first practical guided torpedo.]]
It was designed to run at a consistent depth of {{convert|12|ft|m|order=flip|0}}, and was fitted with an indicator mast that just broke the surface of the water. At night the mast had a small light, visible only from the rear. Two steel drums were mounted one behind the other inside the torpedo, each carrying several thousand metres of high-tensile steel wire. The drums connected via a [[Differential (mechanical device)|differential gear]] to twin [[contra-rotating]] propellers. If one drum was rotated faster than the other, then the rudder was activated. The other ends of the wires were connected to steam-powered winding engines, which were arranged so that speeds could be varied within fine limits, giving sensitive steering control for the torpedo.<ref>National Archive in WO32/6064 In minute to Director of Artillery from Inspector General of Fortifications.</ref>

The torpedo attained a speed of {{convert|20|kn|kph}} using a wire {{convert|0.04|in|mm|order=flip}} in diameter, but later this was changed to {{convert|0.07|in|mm|order=flip|abbr=on}} to increase the speed to {{convert|27|kn|kph}}. The torpedo was fitted with elevators controlled by a depth-keeping mechanism, and the fore and aft rudders operated by the differential between the drums.<ref name="Beanse">The Brennan Torpedo by Alec Beanse {{ISBN|978-0-9548453-6-0}}</ref>

Brennan traveled to Britain, where the Admiralty examined the torpedo and found it unsuitable for shipboard use. However, the [[War Office]] proved more amenable, and in early August 1881, a special [[Royal Engineer]] committee was instructed to inspect the torpedo at Chatham and report back directly to the Secretary of State for War, [[Hugh Childers]]. The report strongly recommended that an improved model be built at government expense. In 1883 an agreement was reached between the Brennan Torpedo Company and the government. The newly appointed Inspector-General of Fortifications in England, [[Andrew Clarke (British Army officer, born 1824)|Sir Andrew Clarke]], appreciated the value of the torpedo, and in spring 1883 an experimental station was established at [[Garrison Point Fort]], [[Sheerness]], on the [[River Medway]], and a workshop for Brennan was set up at the [[Chatham Barracks]], the home of the Royal Engineers. Between 1883 and 1885 the Royal Engineers held trials, and in 1886 the torpedo was recommended for adoption as a harbor defense torpedo. It was used throughout the [[British Empire]] for more than fifteen years.<ref name="Beanse" />

===Use in conflict===
[[File:Combate de Caldera.JPG|thumb|right|Sinking of Chilean ironclad {{ship|Chilean ironclad|Blanco Encalada||2}} by a torpedo in the [[Battle of Caldera Bay]], during the [[Chilean Civil War of 1891]].]]
The [[Royal Navy]] frigate {{HMS|Shah|1873|6}} was the first naval vessel to fire a self-propelled torpedo in anger during the [[Battle of Pacocha]] against rebel Peruvian ironclad {{ship||Huáscar|ironclad|2}} on 29 May 1877. The Peruvian ship successfully outran the device.<ref>{{Cite book|title = Ironclads At War: The Origin And Development Of The Armored Battleship |last1 = Greene |first1 = Jack |publisher = Da Capo Press |location=Pennsylvania |year = 1997|isbn = 0-78674-298-4 |pages = 290|last2 = Massignani |first2 = Alessandro }}</ref> On 16 January 1878, the Turkish steamer ''Intibah'' became the first vessel to be sunk by self-propelled torpedoes, launched from torpedo boats operating from the tender {{ship|Russian tender|Velikiy Knyaz Konstantin||2}} under the command of [[Stepan Osipovich Makarov]] during the [[Russo-Turkish War of 1877–78]].

In another early use of the torpedo, during the [[War of the Pacific]], the Peruvian [[ironclad]] [[Huáscar (ironclad)|Huáscar]] commanded by captain [[Miguel Grau Seminario|Miguel Grau]] attacked the [[Chilean corvette Abtao]] on 28 August 1879 at [[Antofagasta]] with a self-propelled [[John Louis Lay|Lay torpedo]] only to have it reverse course. The ''Huascar'' was saved when an officer jumped overboard to divert it.<ref>{{cite web |url=http://www.unjbg.edu.pe/libro/Basadre/la_Verdadera_epopeya/epopeya_cap2.pdf |title=El Huáscar Muralla Móvil Del Perú |first=Eduardo |last=Avaroa |work=[[Jorge Basadre Grohmann National University|Universidad Nacional Jorge Basadre Grohmann]] |year=2013 |accessdate=31 August 2013 |language=es |archive-url=https://web.archive.org/web/20160304071732/http://www.unjbg.edu.pe/libro/Basadre/la_Verdadera_epopeya/epopeya_cap2.pdf |archive-date=4 March 2016 |url-status=dead }}</ref>

The Chilean [[ironclad]] {{ship|Chilean ironclad|Blanco Encalada||2}} was sunk on 23 April 1891 by a self-propelled torpedo from the ''Almirante Lynch'', during the [[Chilean Civil War of 1891]], becoming the first ironclad warship sunk by this weapon.<ref>{{cite book |last=Scheina |first=Robert L. |date=1987 |title=Latin America: A Naval History, 1810–1987  |publisher=Naval Institute Press |isbn=0-87021-295-8 |page=64 }}</ref> The Chinese [[turret ship]] {{ship|Chinese turret ship|Dingyuan||2}} was purportedly hit and disabled by a torpedo after numerous attacks by Japanese torpedo boats during the [[First Sino-Japanese War]] in 1894. At this time torpedo attacks were still very close range and very dangerous to the attackers.

[[File: Knyaz'Suvorov1904Reval.jpg|thumb|left|{{ship|Russian battleship|Knyaz Suvorov||2}} was sunk by Japanese torpedo boats during the [[Russo-Japanese War]].]]
Several western sources reported that the [[Qing dynasty]] Imperial Chinese military, under the direction of [[Li Hongzhang]], acquired ''electric torpedoes,'' which they deployed in numerous waterways, along with fortresses and numerous other modern military weapons acquired by China.<ref>{{cite book |url=https://books.google.com/books?id=Z1U4AAAAIAAJ&pg=PA425 |title=Overland monthly and Out West magazine|editor-first=Bret |editor-last=Harte|year=1886 |publisher=A. Roman & Company|location=San Francisco, California|page=425|oclc=10002180}}</ref> At the [[Tianjin|Tientsin]] Arsenal in 1876, the Chinese developed the capacity to manufacture these "electric torpedoes" on their own.<ref>{{cite book|url=https://books.google.com/books?id=pEfWaxPhdnIC&pg=PA249 |title=The Cambridge History of China: Late Ch'ing, 1800–1911 Part 2 |editor-first=John King 
 |editor-last=Fairbank |editor-first2=Kwang-Ching |editor-last2=Liu|editor1-link=John K. Fairbank|editor2-link=Kwang-Ching Liu |year=1980 |publisher=Cambridge University Press |page=249|isbn=0-521-22029-7}}</ref> Although a form of Chinese art, the [[Nianhua]], depict such torpedoes being used against Russian ships during the [[Boxer Rebellion]], whether they were actually used in battle against them is undocumented and unknown.<ref>{{cite book|url=https://books.google.com/books?id=wWvl9O4Gn1UC&pg=PA204 |title=Some Did it for Civilisation, Some did it for Their Country: A Revised View of the Boxer War |first=Jane E. |last=Elliott |year=2002 |publisher=Chinese University Press|location=Hong Kong |page=204 |isbn=962-996-066-4}}</ref>

The [[Russo-Japanese War]] (1904–1905) was the first great war of the 20th century.<ref>{{Harvard citation no brackets|Olender|2010|p=233}}</ref>  During the war, the [[Imperial Russian]] and [[Imperial Japanese]] navies launched nearly 300 torpedoes at each other, all of them of the "self-propelled automotive" type.<ref>{{Harvard citation no brackets|Olender|2010|p=236}}</ref>  The deployment of these new underwater weapons resulted in one battleship, two armored cruisers, and two destroyers being sunk in action, with the remainder of the roughly 80 warships being sunk by the more conventional methods of gunfire, mines, and [[scuttling]].<ref>{{Harvard citation no brackets|Olender|2010|p=234}}</ref>

On 27 May 1905, during the [[Battle of Tsushima]], Admiral [[Zinovy Rozhestvensky|Rozhestvensky]]'s [[flagship]], the battleship {{ship|Russian battleship|Knyaz Suvorov||2}}, had been gunned to a wreck by [[Tōgō Heihachirō|Admiral Tōgō]]'s {{cvt|12|in|4=-gunned|adj=mid|order=flip}} [[battleline]].  With the Russians sunk and scattering, Tōgō prepared for pursuit, and while doing so ordered his [[torpedo boat destroyer]]s (TBDs) (mostly referred to as just ''destroyers'' in most written accounts) to finish off the Russian battleship. ''Knyaz Suvorov'' was set upon by seventeen torpedo-firing warships, ten of which were destroyers and four torpedo boats. Twenty-one torpedoes were launched at the [[pre-dreadnought]], and three struck home, one fired from the destroyer {{ship|Japanese destroyer|Murasame|1903|2}} and two from torpedo boats ''No. 72'' and ''No. 75''.<ref>{{Harvard citation no brackets|Olender|2010|p=235}}</ref>  The flagship slipped under the waves shortly thereafter, taking over 900 men with her to the bottom.<ref>{{Harvard citation no brackets|Olender|2010|p=225}}</ref>

On December 9, 1912, the Greek submarine "Dolphin" launched a torpedo against the Ottoman cruiser "Medjidieh".<ref>[https://www.hellenicnavy.gr/el/istoria/palaia-polemika-ploia/229-gr/istoria/palaia-polemika-ploia/ellinika-ypovryxia-kata-tous-valkanikoys-polemous/1728-katadyomeno-delfin.html "Submersible Dolphin", Hellenic Navy] (in Greek)</ref>

===Aerial torpedo===
[[File:1915 Aerial torpedo.jpg|thumb|right|upright|In 1915, Rear Admiral [[Bradley A. Fiske]] conceived of the [[aerial torpedo]].]]

The end of the Russo-Japanese War fueled new theories, and the idea of dropping lightweight torpedoes from aircraft was conceived in the early 1910s by [[Bradley A. Fiske]], an officer in the [[United States Navy]].<ref name="Hopkins">Hopkins, Albert Allis. ''The Scientific American War Book: The Mechanism and Technique of War'', Chapter XLV: Aerial Torpedoes and Torpedo Mines. Munn & Company, Incorporated, 1915</ref> Awarded a patent in 1912,<ref>{{US patent reference|number=1032394|y=1912|m=07|d=16|inventor=Bradley A. Fiske|title=Method of and apparatus for delivering submarine torpedoes from airships}}</ref><ref name="Hart">Hart, Albert Bushnell. ''Harper's pictorial library of the world war, Volume 4''. Harper, 1920, p. 335.</ref> Fiske worked out the mechanics of carrying and releasing the [[aerial torpedo]] from a [[bomber]], and defined tactics that included a night-time approach so that the target ship would be less able to defend itself. Fiske determined that the notional [[torpedo bomber]] should descend rapidly in a sharp spiral to evade enemy guns, then when about {{convert|10|to|20|ft|m|order=flip|0}} above the water, the aircraft would straighten its flight long enough to line up with the torpedo's intended path. The aircraft would release the torpedo at a distance of {{convert|1500|to|2000|yd|-2|order=flip}} from the target.<ref name=Hopkins/> Fiske reported in 1915 that, using this method, enemy fleets could be attacked within their harbors if there was enough room for the torpedo track.<ref>{{cite web |work=The New York Times |date=23 July 1915 |url=https://query.nytimes.com/gst/abstract.html?res=9B00E6D71038E633A25750C2A9619C946496D6CF |title=Torpedo Boat That Flies. Admiral Fiske Invents a Craft to Attack Fleets in Harbors |access-date=29 September 2009}}</ref>

Meanwhile, the [[Royal Naval Air Service]] began actively experimenting with this possibility. The first successful aerial torpedo drop was performed by Gordon Bell in 1914 – dropping a Whitehead torpedo from a [[Short Brothers|Short S.64]] [[seaplane]]. The success of these experiments led to the construction of the first purpose-built operational torpedo aircraft, the [[Short Type 184]], built-in 1915.<ref>{{cite book|url=https://books.google.com/books?id=6z7quhWS-BoC|title=Aircraft Carriers: A History of Carrier Aviation and Its Influence on World Events, Volume II: 1946–2006 |first=Norman |last=Polmar|year=2008|publisher=Potomac Books, Inc. |location=Washington, D.C. |page=16 |isbn=978-1-57488-665-8}}</ref>

[[File: Short 184.jpg|thumb|left|The [[Short Type 184]] was the first torpedo aircraft when built-in 1915.]]
An order for ten aircraft was placed, and 936 aircraft were built by ten different British aircraft companies during the [[First World War]]. The two prototype aircraft were embarked upon {{HMS|Ben-my-Chree}}, which sailed for the [[Aegean Sea|Aegean]] on 21 March 1915 to take part in the [[Gallipoli campaign]].<ref>{{cite book|first=C. H. |last=Barnes |title=Shorts Aircraft Since 1900 |location=London |publisher=Putnam|year=1967|page=113 |oclc=463063844}}</ref> On 12 August 1915 one of these, piloted by [[Flight Commander]] [[Charles H. K. Edmonds|Charles Edmonds]], was the first aircraft in the world to attack an enemy ship with an air-launched torpedo.<ref name="Guinness" >{{cite book|title=Guinness Book of Air Facts and Feats|edition=3rd|year=1977 |publisher=Book Club Associates |location=London |oclc=11494729 |quote=The first air attack using a torpedo dropped by an airplane was carried out by Flight Commander Charles H. K. Edmonds, flying a Short 184 seaplane from ''Ben-my-Chree'' on 12 August 1915, against a 5,000-ton Turkish supply ship in the [[Sea of Marmara]]. Although the enemy ship was hit and sunk, the captain of a British submarine claimed to have fired a torpedo simultaneously and sunk the ship. It was further stated that the British submarine E14 had attacked and immobilized the ship four days earlier.}}</ref>

On 17 August 1915 Flight Commander Edmonds torpedoed and sank an Ottoman transport ship a few miles north of the Dardanelles. His formation colleague, [[Flight Lieutenant]] G B Dacre, was forced to land on the water owing to engine trouble but, seeing an enemy [[tug]] close by, taxied up to it and released his torpedo, sinking the tug. Without the weight of the torpedo, Dacre was able to take off and return to ''Ben-My-Chree''.<ref>{{cite web |last=Bruce |first=J. M. |url=http://www.flightglobal.com/pdfarchive/view/1956/1956%20-%201835.html |title=The Short Seaplanes: Historic Military Aircraft No. 14: Part 3 |work=[[Flight International|Flight]] |date=28 December 1956 |pages=1000}}</ref>

===World War I===
[[File: Bundesarchiv DVM 10 Bild-23-61-28, Am Torpedorohr.jpg|thumb|Launching a torpedo in 1915 during [[World War I]]]]
[[File:Момент вылета мины из орудия (1916).png|thumb|Torpedo launch in 1916]]

Torpedoes were widely used in [[World War I]], both against shipping and against submarines.<ref name=uboat>{{cite web |url=https://uboat.net/wwi/fates/losses.html |title=U-boat Losses 1914–1918 |website=uboat.net |access-date=10 December 2018}}</ref> Germany disrupted the supply lines to Britain largely by use of submarine torpedoes, though submarines also extensively used guns. Britain and its allies also used torpedoes throughout the war. U-boats themselves were often targeted, twenty being sunk by torpedo.<ref name=uboat/> Two Royal Italian Navy [[MAS (boat)|torpedo boats]] scored a success against an Austrian-Hungarian [[Squadron (naval)|squadron]], sinking the battleship {{SMS|Szent István}} with two torpedoes.

The Royal Navy had been experimenting with ways to further increase the range of torpedoes during World War 1 using pure oxygen instead of compressed air, this work ultimately leading to the development of the oxygen-enriched air [[British 24.5 inch torpedo|{{cvt|24.5|in|cm|order=flip}} Mk. I]] intended originally for the {{sclass2|G3|battlecruiser|2}}<nowiki/>s and {{sclass2|N3|battleship|4}} battleships of 1921, both of which were cancelled due to the [[Washington Naval Treaty]].

Initially, the [[Imperial Japanese Navy]] purchased Whitehead or Schwartzkopf torpedoes but by 1917, like the Royal Navy, they were conducting experiments with pure oxygen instead of compressed air. Because of explosions, they abandoned the experiments but resumed them in 1926 and by 1933 had a working torpedo. They also used conventional [[#Wet heater|wet heater]] torpedoes.

=== 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]]. 

By contrast, during the Second World War, Japanese torpedoes were superb.<ref>{{cite web |first = Kent|last = Budge|url=http://pwencycl.kgbudge.com/T/o/Torpedoes.htm|title=The Pacific War Online Encyclopedia: Torpedoes}}</ref> Japan had placed an emphasis on the weapon following numerous successes during the [[First Sino-Japanese War|First Sino-Japanese]] and [[Russo-Japanese War|Russo-Japanese]] wars. The development of [[Japanese 61 cm torpedo|61 cm torpedoes]] was borne out of a concept to use them as a decisive heavy weapon to work around the limitations of the [[Washington Naval Treaty]], alongside other advances such as [[radar]].<ref>{{cite book|first = Thomas|last = Hone|title = The Effectiveness of the "Washington Treaty" Navy, Naval War College Review, Vol.32, No.6|publisher = [[Naval War College Review]]|url=https://www.jstor.org/stable/44641963|date = 1979|page=57}}</ref> Furthermore, before the outbreak of war, Japan had expected to use the submarine (as opposed to the aircraft carrier) as the decisive combatant with which to harass and decimate the United States Navy, a decision which eventually proved to be disastrously incorrect.<ref>{{cite book|first1 = Carl|last1 = Boyd|first2 = Akihiko|last2 = Yoshida|title = The Japanese Submarine Force and World War II|chapter = Basic Concepts of Submarine Strategy and Tactics|publisher = Bluejacket Books|date = 1995|isbn=1-55750-015-0|page=3-5}}</ref> In order to equip their navy with effective torpedoes, numerous advances such as the use of pure oxygen, turbines, and regenerative cooling were experimented with. Torpedo designs were rigorously tested and ascertained to be reliable. The Japanese were also more willing to conduct dangerous experiments and accept the resulting casualties, an attitude that was also reflected in their highly realistic fleet exercises.

Another notable exception to the pre-war neglect of torpedo development was the {{cvt|45|cm|in}}, 1931-premiered Japanese [[Type 91 torpedo]], one of [[Japanese 45 cm torpedo|several aerial torpedoes]] (''Koku Gyorai'') developed and brought into service by the Japanese Empire before the war. In December of 1941, the Type 91 was by far the best aerial torpedo in the world.<ref>{{cite web|website=[[Pearl Harbor Aviation Museum]]|url=https://www.pearlharboraviationmuseum.org/news/blog-archives/pearl-harbor-thunderfish-in-the-sky/|title=Pearl Harbor: Thunderfish in the Sky|access-date=12 October 2024}}</ref> The Type 91 could withstand far higher airdrop speeds than its contemporaries, had an advanced [[PID controller]], and was equipped with breakaway wooden[[Type 91 torpedo#Kyoban stabilizer plates|'' Kyoban'' underwater stabilizing surfaces]] which detached after entering the water, making it a formidable anti-ship weapon; Germany considered manufacturing it as the [[List of World War II torpedoes of Germany#List of World War II Luftwaffe torpedoes|LT 850]] [[Yanagi missions|after August 1942]].

The Royal Navy's {{cvt|24.5|in|cm|order=flip|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="Washington">'' 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|cm|order=flip|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-inch Mark 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-inch Mark VIII]] torpedo of 1925. This torpedo served throughout WWII and remained in service until the early 1990s. 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 Mod 4 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'']].
{{clear}}

[[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 [[aerial torpedo]]es into a Type 429 Mark VIII [[Vickers Wellington]] [[maritime patrol aircraft]], May 1942.]]

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>

=== Frequency-hopping ===
{{main|Hedy Lamarr}}
During [[World War II]], [[Hedy Lamarr]] and composer [[George Antheil]] developed a radio guidance system for [[Allies of World War II|Allied]] torpedoes; it intended to use [[frequency-hopping]] technology to defeat the threat of [[Radio jamming|jamming]] by the [[Axis powers]]. As radio guidance had been abandoned some years earlier, it was not pursued.<ref name="EFF1997">{{cite press release|title=Movie Legend Hedy Lamarr to be Given Special Award at EFF's Sixth Annual Pioneer Awards|publisher=Electronic Frontier Foundation|date=March 11, 1997|url=http://w2.eff.org/awards/pioneer/1997.php|access-date=February 1, 2014|url-status=dead|archive-url=https://web.archive.org/web/20071016063043/http://w2.eff.org/awards/pioneer/1997.php|archive-date=October 16, 2007|df=mdy-all}}</ref> Although the [[US Navy]] never adopted the technology, it did, in the 1960s,<ref>{{Cite web|url=https://www.eetimes.com/document.asp?doc_id=1279374|title=short history of spread spectrum|date=26 January 2012|website=Electronic Engineering (EE) Times|archive-url=https://web.archive.org/web/20180826005036/https://www.eetimes.com/document.asp?doc_id=1279374|archive-date=August 26, 2018|url-status=live|df=mdy-all}}</ref> investigate various spread-spectrum techniques. Spread-spectrum techniques are incorporated into [[Bluetooth]] technology and are similar to methods used in legacy versions of [[Wi-Fi]].<ref name="newscientist20112">[https://www.newscientist.com/blogs/culturelab/2011/12/hedylamarr.html "Hollywood star whose invention paved the way for Wi-Fi"], ''New Scientist'', December 8, 2011; retrieved February 4, 2014.</ref><ref name="WiredEFF2">{{cite magazine|url=http://archive.wired.com/politics/law/news/1997/03/2507|access-date=November 9, 2013|title=Privacy Implications of Hedy Lamarr's Idea|magazine=Wired|publisher=Condé Nast Digital|date=March 11, 1997|first=Ashley|last=Craddock|archive-url=https://web.archive.org/web/20150805043848/http://archive.wired.com/politics/law/news/1997/03/2507|archive-date=August 5, 2015|url-status=live|df=mdy-all}}</ref><ref name="NYT19412">{{cite news|url=http://ipmall.info/hosted_resources/nic/nic_LamarrNYT.pdf|title=Hedy Lamarr Inventor|work=The New York Times|date=October 1, 1941|access-date=February 1, 2014|url-status=dead|archive-url=https://web.archive.org/web/20160410084732/http://ipmall.info/hosted_resources/nic/nic_LamarrNYT.pdf|archive-date=April 10, 2016|df=mdy-all}}</ref> This work led to their induction into the [[National Inventors Hall of Fame]] in 2014.<ref name="EFF1997"/><ref>{{cite web|url=http://invent.org/inductee-detail/?IID=501|title=Spotlight – National Inventors Hall of Fame|publisher=invent.org|access-date=May 26, 2015|archive-url=https://web.archive.org/web/20150501105813/http://invent.org/inductee-detail/?IID=501|archive-date=May 1, 2015|url-status=live|df=mdy-all}}</ref>

=== Post–World War II ===
[[File:Type 123K Torpedo boat Bangladesh Navy T 8224 (23317190180).jpg|thumb|Decommissioned [[P 4-class torpedo boat]] of the [[Bangladesh Navy]]. Preserved at the [[Bangabandhu Military Museum]].]] 
Because of improved submarine strength and speed, torpedoes had to be given improved warheads and better motors. During the [[Cold War]], torpedoes were an important asset with the advent of [[nuclear-powered submarine]]s, which did not have to surface often, particularly those carrying strategic [[nuclear missile]]s.

Several navies have launched torpedo strikes since World War II, including:
* During the [[Korean War]], the United States Navy successfully attacked a dam with air-launched torpedoes.<ref>{{cite book |last=Faltum |first=Andrew |title=The Essex Aircraft Carriers
|publisher=The Nautical & Aviation Publishing Company of America |year=1996 |location=Baltimore, Maryland |pages=125–126 |isbn=1-877853-26-7}}</ref>
* Israeli Navy [[fast attack craft]] crippled the American electronic intelligence vessel [[USS Liberty incident|USS ''Liberty'']] with gunfire and torpedoes during the 1967 [[Six-Day War]], resulting in the loss of 34 crew.
* A [[Pakistan Navy]] {{sclass|Daphné|submarine|2}} sank the Indian frigate {{INS|Khukri|1958|6}} on 9 December 1971 during the [[Indo-Pakistani War of 1971]], with the loss of over 18 officers and 176 sailors.
* The British Royal Navy nuclear attack submarine {{HMS|Conqueror|S48|6}} sank the [[Argentine Navy]] [[light cruiser]] {{ship|ARA|General Belgrano}} on 2 May 1982 with two [[British 21 inch torpedo#21 inch Mark VIII|Mark 8]] torpedoes during the [[Falklands War]] with the loss of 323 lives.
* On 16 June 1982, during the [[1982 Lebanon War|Lebanon War]], an unnamed [[Gal-class submarine|Israeli submarine]] torpedoed and sank the Lebanese coaster ''Transit'',<ref name="www.marhisdata.nl">{{Cite web |last= |first= |date= |title=Stichting Maritiem Historische Data - Schip |url=https://www.marhisdata.nl/schip&id=2654 |access-date=11 February 2021 |website=www.marhisdata.nl |language=dutch}}</ref> which was carrying 56 Palestinian refugees to [[Cyprus]], in the belief that the vessel was evacuating anti-Israeli militias. The ship was hit by two torpedoes, managed to run aground but eventually sank. There were 25 dead, including her captain. The [[Israeli Navy]] disclosed the incident in November 2018.<ref>{{cite news |last= |first= |date=22 November 2018 |title=Israel admits it sank Lebanese refugee boat in 1982 war error, killing 25 — TV |url=https://www.timesofisrael.com/israel-admits-it-sank-lebanese-refugee-boat-in-1982-war-error-killing-25-tv/ |access-date=11 February 2021 |website=[[The Times of Israel]] |language=en-US |issn=0040-7909}}</ref><ref name="www.marhisdata.nl" />
* The [[Croatian Navy]] disabled the Yugoslav patrol boat [[PČ-176 Mukos|PČ-176 ''Mukos'']] with a torpedo launched by Croatian [[Frogman|naval commandos]] from an improvised device during the [[Battle of the Dalmatian channels]] on 14 November 1991, in the course of the [[Croatian War of Independence]]. Three members of the crew were killed. The stranded boat was later recovered by Croatian trawlers, salvaged, and put in service with the Croatian Navy as OB-02 ''Šolta''.<ref>{{cite web |url=http://uhddr-hrm.com/clanci/2011/premijera-hrvatskog-minitorpeda.html |title=Premijera hrvatskog monitored |first=Stjepan Bernadić |last=Kula |language=hr |access-date=10 December 2018 |archive-date=29 November 2018 |archive-url=https://web.archive.org/web/20181129012738/http://uhddr-hrm.com/clanci/2011/premijera-hrvatskog-minitorpeda.html |url-status=dead }}</ref>
* On 26 March 2010, the South Korean Navy ship [[ROKS Cheonan sinking|ROKS ''Cheonan'']] was sunk with the loss of 46 personnel. A subsequent investigation concluded that the warship had been sunk by a North Korean torpedo fired by a [[Yono-class submarine|midget submarine]].<ref>{{Cite web |date=2010-09-13 |title=Seoul reaffirms N. Korea's torpedo attack in final report |url=https://www.koreatimes.co.kr/www/news/nation/2010/09/205_72997.html |access-date=2024-12-14 |website=The Korea Times |language=en}}</ref>

== Propulsion ==
[[File: US Navy inactive torpedo launch.jpg|thumb|right|{{USS|Mustin|DDG-89|6}} launches a dummy torpedo during exercises.]]

===Compressed air===
The Whitehead torpedo of 1866, the first successful self-propelled torpedo, used [[Pneumatics|compressed air]] as its energy source. The air was stored at pressures of up to {{convert|2.55|MPa|abbr=on}} and fed to a [[piston engine]] that turned a single [[propeller]] at about 100 [[Revolutions per minute|rpm]]. It could travel about {{convert|180|m|yard}} at an average speed of {{convert|6.5|kn|km/h|lk=in}}. The speed and range of later models were improved by increasing the pressure of the stored air. In 1906 Whitehead built torpedoes that could cover nearly {{convert|1000|m|yard}} at an average speed of {{convert|35|kn|km/h}}.

At higher pressures the [[Adiabatic process#Adiabatic heating and cooling|adiabatic cooling]] experienced by the air as it expanded in the engine caused icing problems. This drawback was remedied by heating the air with seawater before it was fed to the engine, which increased engine performance further because the air expanded even more after heating. This was the principle used by the Brotherhood engine.

===Heated torpedoes===
Torpedoes propelled by compressed air encountered a significant problem when attempts were made to increase their range and speed. The cold compressed air, upon entering the expansion phase in the piston chambers of the torpedo's engine, caused a rapid drop in temperature. This could freeze the engine solid, by jamming the piston heads inside the cylinders. This led to the idea of injecting a liquid fuel, like [[kerosene]], into the compressed air and igniting it inside a separate expansion chamber. In this manner, the air is heated more and expands even further, and the burned propellant adds more gas to drive the engine. The earliest form was the "Elswick" heater as patented by [[Armstrong Whitworth]] in 1904. The device was demonstrated in an {{cvt|18|in|cm|order=flip|adj=on}} Fiume Mark III torpedo at [[Bincleaves Groyne|Bincleaves]] in 1905 before an audience of British and Japanese experts. The weapon speed was {{cvt|9|kn|kph}} more than for the otherwise-identical unheated version. Construction of such ''heated'' torpedoes started the same year by Whitehead's company.<ref>{{cite book|first = Geoff|last = Kirby|title = JRNSS Volume 27, No.1 - A History of the Torpedo, The Early Days|publisher = Journal of the Royal Navy Scientific Service|date = January 1972|url=https://archive.org/details/DTIC_AD0595766|pages=43–44}}</ref>

==== Dry heater ====

The earliest production version of the heated torpedo propulsion system, which became known as the Whitehead heater system, mixed the fuel and compressed air after the pressure regulator. Combustion took place in a specialized expansion chamber, with hot combustion products driving the pistons of a reciprocating engine. This had the disadvantage of badly sooting the air vessel with combustion byproducts, and could also engage in a [[thermal runaway]], jamming the engine—not from low temperature as observed with compressed air, but from excess heat. The "dry heater" distinction was only made after wet heater torpedoes were developed, prior to which all heated torpedoes were of the dry heater type—originally simply called "heated".

==== Wet heater ====
{{Anchor|Wet heater|Wet-heater}}A further improvement was the use of water to wash and cool the [[combustion chamber]] of the fuel-burning torpedo. Water would be injected into the combustion chamber, at a rate commensurate with the fuel supply rate. This water would flash to steam, with stray condensate carrying the soot combustion byproducts out through the engine. An early example was the wet heater system developed by Lieutenant Sydney Hardcastle at the [[Royal Arsenal|Royal Gun Factory]], in 1908.<ref>{{cite book|chapter=The Officers of the Royal Navy Before 1918|chapter-url=https://link.springer.com/content/pdf/10.1057/9781137481962_2.pdf|website=Springer Link|date=2015 |doi=10.1057/9781137481962_2 |access-date=4 October 2024|chapter-url-access=subscription |last1=Farquharson-Roberts |first1=Mike |title=Royal Naval Officers from War to War, 1918–1939 |pages=8–23 |isbn=978-1-349-57163-5 }}</ref> The compressed air bottle was partially filled with water, with an outlet at the bottom leading into the combustion chamber. This would guarantee that compressed air and water would be injected into the combustion chamber at the same pressure. The system not only solved heating problems so more fuel could be burned but also allowed additional power to be generated by feeding the resulting steam into the engine together with the [[combustion]] products. Torpedoes with such a propulsion system became known as ''wet heaters'', while heated torpedoes without steam generation were retrospectively called ''dry heaters''. Most torpedoes used in World War I and World War II were wet heaters.

==== Increased oxidant ====
The amount of fuel that can be burned by a torpedo engine (i.e. wet engine) is limited by the amount of [[oxygen]] it can carry. Since compressed [[Atmosphere of Earth#Composition|air contains only about 21% oxygen]], engineers in Japan developed the [[Type 93 torpedo|Type 93]] (nicknamed "Long Lance" postwar)<ref name="Morison, Samuel Eliot 1950 p.195" /> for destroyers and cruisers in the 1930s. It used pure compressed oxygen instead of compressed air and had performance unmatched by any contemporary torpedo in service, through the end of World War II. However, oxygen systems posed a danger to ships carrying such torpedoes under normal operation, and more so under attack; Japan lost several cruisers partly due to catastrophic secondary explosions of Type&nbsp;93s.

During World War II, Germany experimented with [[hydrogen peroxide]] for the same purpose.

The British approached the problem of providing additional oxygen for the torpedo engine by the use of oxygen-enriched air rather than pure oxygen: up to 57% instead of the 21% of normal atmospheric compressed air. This significantly increased the range of the torpedo, the {{cvt|24.5|in|cm|order=flip|adj=on}} Mk 1 having a range of {{convert|15000|yard|m|order=flip}} at {{convert|35|kn|km/h}} or {{convert|20000|yard|m|order=flip}} at {{convert|30|kn|km/h}} with a {{convert|750|lb|kg|adj=on|order=flip}} warhead. There was a general nervousness about the oxygen enrichment equipment, known for reasons of secrecy as "No 1 Air Compressor Room" on board ships, and development shifted to the highly efficient Brotherhood Burner Cycle engine that used un-enriched air.<ref name="Washington"/>

==== Burner cycle engine ====
After the First World War, [[Peter Brotherhood]] developed a four-cylinder burner cycle engine which was roughly twice as powerful as the older wet heater engine. It was first used in the British Mk VIII torpedoes, which were still in service in 1982. It used a modified diesel cycle, using a small amount of paraffin to heat the incoming air, which was then compressed and further heated by the piston, and then more fuel was injected. It produced about {{Convert|322|hp|kW|order=flip}} when introduced, but by the end of WWII was at {{Convert|465|hp|kW|order=flip}}, and there was a proposal to fuel it with nitric acid, in which it was projected to develop {{Convert|750|hp|kW|order=flip}}.<ref>Torpedo: The Complete History of the World's Most Revolutionary Naval Weapon
By Roger Branfill-Cook</ref>

===Wire driven===
[[File:TorpedoMotor.JPG|right|thumb|U.S. World War II [[PT boat]] torpedo<!--Mk 8? Or Mk13?--> on display]]
The [[Brennan torpedo]] had two wires wound around internal drums joined to the propellers. Shore-based steam [[winch]]es pulled the wires, which spun the internal drums and drove the propellers. An operator controlled the relative speeds of the winches, providing guidance. Such systems were used for [[Coastal defense and fortification|coastal defense]] of the British homeland and colonies from 1887 to 1903 and were purchased by, and under the control of, the Army as opposed to the Navy. Speed was about {{convert|25|kn|km/h|0}} for over {{Convert|2400|m|yd}}.

===Flywheel===
The [[Howell torpedo]] used by the [[US Navy]] in the late 19th century featured a heavy [[flywheel]] that had to be spun up before launch. It was able to travel about {{convert|400|yd|m|order=flip}} at {{convert|25|kn|km/h}}. The Howell had the advantage of not leaving a trail of bubbles behind it, unlike compressed air torpedoes. This gave the target vessel less chance to detect and evade the torpedo and avoided giving away the attacker's position. Additionally, it ran at a constant depth, unlike Whitehead models.

===Electric batteries===
{{Anchor|Electric batteries}}
[[File:Torpedo model Z-13 mg 5165.jpg|thumb|Electric batteries of a French [[Z13 torpedo]]]]

Electric propulsion systems avoided tell-tale bubbles. [[John Ericsson]] invented an electrically propelled torpedo in 1873; it was powered by a cable from an external power source, because [[Battery (electricity)|batteries]] of the time had insufficient capacity. The Sims-Edison torpedo was similarly powered. The Nordfelt torpedo was also electrically powered and was steered by impulses down a trailing wire.

Germany introduced its first battery-powered torpedo shortly before World War II, the [[G7e]]. It was slower and had a shorter range than the conventional [[G7a]], but was wakeless and much cheaper. Its [[lead–acid battery|lead-acid]] [[rechargeable battery]] was sensitive to shock, required frequent maintenance before use, and required preheating for best performance. The experimental [[G7es]], an enhancement of the G7e, used [[primary cell]]s.

The United States had an electric design, the [[Mark 18 torpedo|Mark 18]], largely copied from the German torpedo (although with improved batteries), as well as [[Mark 24 Mine|FIDO]], an air-dropped acoustic homing torpedo for anti-submarine use.

Modern electric torpedoes such as the [[Mark 24 Tigerfish]], the [[Black Shark torpedo|Black Shark]] or DM2 series commonly use [[Silver-oxide battery|silver oxide batteries]] that need no maintenance, so torpedoes can be stored for years without losing performance.

===Rockets===
Several experimental rocket-propelled torpedoes were tried soon after Whitehead's invention but were not successful. Rocket propulsion has been implemented successfully by the Soviet Union, for example in the [[VA-111 Shkval]], and has been recently{{When|date=March 2025}} revived in Russian and German torpedoes, as it is especially suitable for [[supercavitating]] devices.<ref>[http://www.geoffkirby.co.uk/rocket-torpedoes.pdf "The Development of Rocket-propelled Torpedoes"] {{Webarchive|url=https://web.archive.org/web/20201108092414/http://www.geoffkirby.co.uk/rocket-torpedoes.pdf |date=2020-11-08 }}, by Geoff Kirby (2000)</ref>

===Modern energy sources===
Modern torpedoes use a variety of propellants, including electric batteries (as with the French [[F21 (torpedo)|F21 torpedo]] or Italian [[Black Shark torpedo|Black Shark]]), [[monopropellant]]s (e.g., [[Otto fuel II]] as with the US [[Mark 48 torpedo]]), and bipropellants (e.g., [[hydrogen peroxide]] plus [[kerosene]] as with the Swedish [[Torped 62]], [[sulfur hexafluoride]] plus [[lithium]] as with the US [[Mark 50 torpedo]], or [[Otto fuel II]] plus hydroxyl ammonium perchlorate as with the British [[Spearfish torpedo]]).

=== Propeller ===
The first of Whitehead's torpedoes had a single propeller and needed a large vane to stop it spinning about its longitudinal axis. Not long afterward the idea of [[contra-rotating|contra-rotating propellers]] was introduced, to avoid the need for the vane. The three-bladed propeller came in 1893 and the four-bladed one in 1897. To minimize noise, today's torpedoes often use [[pump-jet]]s.

=== Supercavitation ===
{{Main|Supercavitating torpedo}}
Some torpedoes—like the Russian [[VA-111 Shkval]], Iranian [[Hoot (missile)|Hoot]], and German [[Superkavitierender Unterwasserlaufkörper|Unterwasserlaufkörper/ Barracuda]]—use [[supercavitation]] to increase speed to over {{convert|200|kn|km/h}}. Torpedoes that do not use supercavitation, such as the American [[Mark 48 torpedo|Mark 48]] and British [[Spearfish torpedo|Spearfish]], are limited to under {{cvt|100|kn|kph}}, though manufacturers and the military do not always release exact figures.

==Guidance==
[[File: Sopwith Cuckoo.jpg|thumb|A torpedo dropped from a [[Sopwith Cuckoo]] during World War I]]
[[File:FiringGeometry.png|thumb|Illustration of General Torpedo Fire Control Problem]]

Torpedoes may be aimed at the target and fired unguided, similarly to a traditional [[artillery shell]], or they may be guided onto the target. They may be guided autonomously towards the target by some procedure, such as sound (homing), or by the operator, typically via commands sent over a signal-carrying cable ([[wire guidance]]).

===Unguided===
The Victorian-era [[Brennan torpedo]] could be steered onto its target by varying the relative speeds of its propulsion cables. However, the Brennan required a substantial infrastructure and was not suitable for shipboard use. Therefore, for the first part of its history, the torpedo was guided only in the sense that its course could be regulated to achieve an intended impact depth (because of the sine-wave running path of the Whitehead,<ref>Fitzsimons, Bernard, ed. "Bliss-Leavitt", in ''The Illustrated Encyclopedia of 20th Century Weapons and Warfare'' (London: Phoebus, 1978), Volume 4, p.386.</ref> this was a hit or miss proposition, even when everything worked correctly) and, through gyroscopes, a straight course. With such torpedoes the method of attack in [[Torpedo boats#Motor torpedo craft|small torpedo boats]], [[torpedo bomber]]s, and small submarines was to steer a predictable collision course abeam to the target and release the torpedo at the last minute, then veer away, all the time subject to defensive fire.

In larger ships and submarines, fire-control calculators gave a wider engagement envelope. Originally, plotting tables (in large ships), combined with specialized [[slide rule]]s (known in U.S. service as the "banjo" and "Is/Was"),<ref name=Beach55>{{cite book |first=Edward L. |last=Beach |title=Run Silent, Run Deep |url=https://books.google.com/books?id=v6D1DAAAQBAJ |orig-year=1955 |date=2016 |publisher=Naval Institute Press |isbn=978-1-68247-167-8}}</ref> reconciled the speed, distance, and course of a target with the firing ship's speed and course, together with the performance of its torpedoes, to provide a firing solution. By the Second World War, all sides had developed automatic electro-mechanical calculators, exemplified by the U.S. Navy's [[Torpedo Data Computer]].<ref>The British called theirs the "fruit machine".</ref> Submarine commanders were still expected to be able to calculate a firing solution by hand as a backup against mechanical failure, and because many submarines existed at the start of the war were not equipped with a TDC; most could keep the "picture" in their heads and do much of the calculations (simple trigonometry) mentally, from extensive training.<ref name=Beach55/>

Against high-value targets and multiple targets, submarines would launch a spread of torpedoes, to increase the probability of success. Similarly, squadrons of torpedo boats and torpedo bombers would attack together, creating a "fan" of torpedoes across the target's course. Faced with such an attack, the prudent thing for a target to do was to turn to parallel the course of the incoming torpedo and steam away from the torpedoes and the firer, allowing the relatively short-range torpedoes to use up their fuel. An alternative was to "comb the tracks", turning to parallel the incoming torpedo's course, but turning towards the torpedoes. The intention of such a tactic was still to minimize the size of the target offered to the torpedoes, but at the same time be able to aggressively engage the firer. This was the tactic advocated by critics of Jellicoe's actions at [[Battle of Jutland#Controversy|Jutland]], his caution at turning away from the torpedoes being seen as the reason the Germans escaped.

The use of multiple torpedoes to engage single targets depletes torpedo supplies and greatly reduces a submarine's [[combat endurance]].<ref>''The Attack Submarine'' suggests ''shorter'' patrols actually improve effectiveness.</ref> Endurance can be improved by ensuring that a target can be effectively engaged by a single torpedo, which gave rise to the guided torpedo.

===Pattern running===
[[File:Flachenabsuchender_Torpedo_type_I_-_running_pattern.svg|thumb|right|The functional concept of torpedoes running a ladder search pattern, launched by two submarines at a moving convoy.]]
During the Second World War, the Germans introduced programmable pattern-running torpedoes, which would run a predetermined pattern until they either ran out of fuel or hit something. These weapons would generally engage in a [[Water surface searches#Parallel track|ladder search pattern]], and were intended for engaging [[convoy]]s of vessels, commonly encountered in the Atlantic theater. The use of pattern-running torpedoes allowed a [[Wolfpack (naval tactic)|wolfpack]] of U-boats to lob large numbers of shots in the general area of a moving convoy, without concern that two different U-boats may be targeting the same vessel.

The earlier version of the weapon, FaT (''Flächenabsuchender'' - "planar seeker"), ran out after launch in a straight line, and then weaved backward and forwards parallel to that initial course, whilst the more advanced LuT (''Lageunabhängiger'' - "position-independent") could transit to a preprogrammed gyrocompass angle after reaching a set distance after launch, and then enter a more complex weaving pattern.<ref>{{cite web | title = U-boat Archive – Interrogation of U-Boat Survivors – Cumulative Edition | url =http://www.uboatarchive.net/KTB/KTBNotesArmamentCumulativeEdition.htm | access-date = 2017-04-13}}</ref>

Germany also used the Italian [[List of World War II torpedoes of Germany|LT 350 aerial torpedo]] for [[Anti-submarine warfare|ASW]]. The weapon lacked an acoustic seeker head, but it would be dropped in clusters over the approximate location of a lurking enemy submarine, and would thereafter engage in a chaotic movement pattern, in order to hit the target by random chance.

A somewhat similar concept for a chaotic underwater pattern search was experimented with by Japan during the Second World War with their [[Japanese 45 cm torpedo#Bomb-Torpedoes|Kūrai No.6 and No.7]] circling ASW bomb-torpedoes. These weapons did not possess homing capabilities, nor a propulsion system; the design resembled a [[Dart (missile)|dart]], and would glide at high speed when launched. The functional concept envisioned multiple such weapons launched directly by an aircraft at a surfaced submarine, or at the approximate location of a submerged one. After splashdown, the weapons would move in a spiral pattern as they sank, their forward movement being enacted by the Earth's gravity.

Acoustic homing torpedoes usually possess the capability to engage in simple search patterns at the launching entity's discretion; the most common of these are the snake (weave left and right while moving forward, to achieve a wider forward-facing detection cone) and the circle (continuously travel in a circle, for omnidirectional detection around the epicenter of the circle) search patterns. A good example of a weapon possessing both of these search patterns is the [[Mark 46 torpedo|Mark 46]] lightweight torpedo, used in large numbers worldwide.

===Radio and wire guidance<span class="anchor" id="Radio and wire guidance"></span>===
{{See also|Command guidance}}
Though Luppis' original design had been rope-guided, and numerous early examples of torpedoes possessed [[Manual command to line of sight|MCLOS]] wire guidance and radio guidance, wire-guided torpedoes did not become common until the 1960s.

[[File:PSM V56 D0325 Launching of patrick torpedo from the ways.png|thumb|A Patrick wire-guided torpedo in launch configuration, circa 1899.]]

[[File:PSM V56 D0325 Patrick torpedo moving at 23 knots per hour.png|thumb|A Patrick wire-guided torpedo moving at 23 knots. The flags were used for line-of-sight control.]]

One of the earliest examples of an electrical wire-guided torpedo was the Lay torpedo, designed by [[John Louis Lay]] between 1867 and 1872.<ref>{{cite web|last = Rigby|first = Rebecca|title = The Lay Torpedoes|url = https://www.torp.esrc.unimelb.edu.au/biogs/E000124b.htm|website = 19th Century Torpedoes, An Annotated Bibliography|access-date = 8 May 2025}}</ref> It would eventually be developed into the Patrick torpedo circa 1899, which was capable of speeds up to {{cvt|23|kn|kph}}.<ref>{{cite web|last = Rigby|first = Rebecca|title = The Patrick Torpedo|url = https://www.torp.esrc.unimelb.edu.au/biogs/E000113b.htm|website = 19th Century Torpedoes, An Annotated Bibliography|access-date = 8 May 2025}}</ref>

The [[Brennan torpedo]] of 1877 was a wire-guided weapon which had an all-mechanical control scheme, and also used the control wires as a source of propulsive energy. By selectively putting more or less tension on the control wires as they were payed out, the weapon could be steered left and right. Line-of-sight control was accomplished by observing a tracking mast which projected above the water from the weapon's body.<ref>{{cite web|last = Rigby|first = Rebecca|title = The Brennan Torpedo|url = https://www.torp.esrc.unimelb.edu.au/biogs/E000123b.htm|website = 19th Century Torpedoes, An Annotated Bibliography|access-date = 8 May 2025}}</ref>

One of the most sophisticated early examples of a radio-controlled torpedo was the Sims-Edison torpedo (circa 1890), later known as the Sims-Shoemaker torpedo (after 1902). The weapon carried a {{cvt|500|lb|kg|order=flip}} [[Gelignite|nitrogelatin]] warhead and was capable of a speed of {{cvt|20|kn|kph}}.<ref>{{cite web|author = Scientific American|title = The Sims-Edison Electric Torpedo - The Torpedo at Full Speed - Sectional View of the Torpedo|url = http://www.scientificamericanpast.com/Scientific%20American%201890%20to%201899/1/lg/sci7261890.htm|website = scientificamericanpast.com|date = 26 July 1890|access-date = 8 May 2025|archive-url = https://web.archive.org/web/20130527115531/http://www.scientificamericanpast.com/Scientific%20American%201890%20to%201899/1/lg/sci7261890.htm|archive-date = 2013-05-27}}</ref><ref>{{cite web|last = Rigby|first = Rebecca|title = The Sims-Edison Torpedo|url = https://www.torp.esrc.unimelb.edu.au/biogs/E000115b.htm|website = 19th Century Torpedoes, An Annotated Bibliography|access-date = 8 May 2025}}</ref> Control signals used code sequences transmitted via radio, in a manner similar to a [[Teleprinter|teletype]]; aside from steering, the weapon could also be remotely armed and detonated, sped up or slowed down, and halted entirely at the operator's discretion. The weapon was effectively impossible to hijack even if an identical command console were possessed by the adversary, and the brevity of command signals would have also enormously complicated radio signal detection and jamming.<ref>{{cite book|first = H. R.|last = Everett|title = Unmanned Systems of World Wars I and II|publisher = [[Massachusetts Institute of Technology]]|date = 2015|isbn = 978-0-262-02922-3|pages=205–211}}</ref>

[[File:330-ps-9119 15540094799 o.jpg|thumb|Artist's impression of a USN Mark 39 wire-guided torpedo approaching a hostile submarine.]]

During the First World War, the U.S. Navy evaluated a radio controlled torpedo launched from a surface ship, called the Hammond torpedo.<ref>{{cite news| url=https://www.nytimes.com/1916/08/29/archives/to-test-hammond-torpedo-general-wood-named-as-head-of-board-to-pass.html | work=The New York Times | title=TO TEST HAMMOND TORPEDO; General Wood Named as Head of Board to Pass Judgment on Invention | date=29 August 1916}}</ref> A later version tested in the 1930s was claimed to have an effective range of {{convert|6|mi|km|order=flip|sigfig=1}}.<ref>{{cite magazine |url=https://books.google.com/books?id=p-IDAAAAMBAJ&pg=PA262 |title=Torpedo Controlled By Radio After Striking Water|magazine=Popular Mechanics |date=February 1930 |publisher=Hearst Magazines}}</ref>

The first major example of a wire-guided torpedo which was used against live targets in warfare was the German [[List of World War II torpedoes of Germany|G7ef ''"Spinne"'']], introduced in 1944, which was a [[G7e torpedo|G7e]] variant equipped with an electronic guidance wire, controlled by means of [[Beam riding|acoustic beam riding]] by the launching entity. Originally intended for use by land emplacements for strait defense, later examples were deployed by submarines.

Another example of a guided torpedo during the Second World War was the [[Helmover torpedo]], which was a colossal aerial torpedo with an overall mass of {{cvt|11500|lb|kg|order=flip}}, carrying a warhead filled with {{cvt|1000|kg|lb}} of [[RDX]] explosive. The Helmover torpedo possessed a vertical mast which projected above the water and shone infrared lights towards the guiding aircraft to indicate its location and orientation, in a manner similar to a [[Precision approach path indicator|PAPI array]]. Guidance signals to the torpedo were transmitted via radio.

The first truly modern electronically wire-guided torpedo was the [[USN]] [[Mark 39 torpedo|Mark 39]], introduced in 1946. It possessed three-dimensional acoustic homing and used a control wire for mid-course guidance. In 1956, the Mark 39 would be superseded by the [[Mark 37 torpedo|Mark 37]], which served as a mainstay [[Anti-submarine warfare|ASW]] weapon during the 1960s.

Another advancement in the field of teleoperated torpedoes was the [[Royal Navy]] [[British 21-inch torpedo#Mark 23 Grog|Mark 23 Grog]], first available in 1959, an ASW weapon which established a direct audio signal link between the hydrophones of the weapon's seeker head and the command console onboard the launching submarine. A human operator would directly listen to the sounds heard by the torpedo, allowing for sophisticated discrimination of acoustic decoys and target recognition.

Modern torpedoes use an [[Umbilical cable|umbilical wire]], which nowadays allows the computer processing power of the submarine or ship to be used. Torpedoes such as the USN [[Mark 48 torpedo|Mark 48]] can operate in a variety of modes, increasing tactical flexibility.

===Homing===
{{Main|Acoustic torpedo|Wake homing}}
Homing "[[fire and forget]]" torpedoes can use passive or active guidance or a combination of both. Passive [[acoustic torpedo]]es home in on emissions from a target. Active acoustic torpedoes home in on the reflection of a signal, or "ping", from the torpedo or its parent vehicle; this has the disadvantage of giving away the presence of the torpedo. In semi-active mode, a torpedo can be fired to the last known position or calculated position of a target, which is then acoustically illuminated ("pinged") once the torpedo is within attack range.

Later in the Second World War, torpedoes were given acoustic (homing) [[guidance system]]s, with the American [[Mark 24 mine]] and [[Mark 27 torpedo]] and the German [[G7es torpedo]]. Pattern-following and [[wake homing|wake-homing]] torpedoes were also developed. Acoustic homing formed the basis for torpedo guidance after the Second World War.

The homing systems for torpedoes are generally acoustic, though there have been other target sensor types used. A ship's [[acoustic signature]] is not the only emission a torpedo can home in on; to engage U.S. [[supercarrier]]s, the [[Soviet Union]] developed the [[53-65 torpedo|53–65]] [[Wake (physics)|wake]]-homing torpedo. As standard acoustic lures cannot distract a wake-homing torpedo, the US Navy has installed the Surface Ship Torpedo Defense on aircraft carriers that use a Countermeasure Anti-Torpedo to home in on and destroy the attacking torpedo.<ref>{{cite news |url=http://nationalinterest.org/blog/the-buzz/the-us-navys-master-plan-save-aircraft-carriers-lethal-17870 |title=The US Navy's Master Plan to Save Aircraft Carriers from Lethal Torpedo Attacks |last1=Osborn |first1=Kris |date=28 September 2016 |website=nationalinterest.org |publisher=The National Interest |access-date=13 October 2016}}</ref>

==Warhead and fuzing==
The [[warhead]] is generally some form of [[aluminum|aluminized]] explosive, because the sustained explosive pulse produced by the powdered aluminum is particularly destructive against underwater targets. [[Torpex]] was popular until the 1950s, but has been superseded by [[polymer bonded explosive|PBX]] compositions. [[Nuclear torpedo]]es have also been developed, such as the [[Mark 45 torpedo]]. In lightweight antisubmarine torpedoes designed to penetrate submarine hulls, a [[shaped charge]] can be used. [[Detonation]] can be triggered by direct contact with the target or by a [[proximity fuze]] incorporating sonar and/or magnetic sensors.

===Contact detonation===
When a torpedo with a contact fuze strikes the side of the target hull, the resulting explosion creates a bubble of expanding gas, the walls of which move faster than the [[Speed of sound#Speed of sound in liquids|speed of sound in water]], thus creating a [[shock wave]]. The side of the bubble which is against the hull rips away the external plating, creating a large breach. The bubble then collapses in on itself, forcing a high-speed stream of water into the breach which can destroy [[Bulkhead (partition)|bulkhead]]s and machinery in its path.<ref name ="Branfill_Cook_2014">{{cite book |last=Branfill-Cook |first=Roger  |date=2014 |title=Torpedo: The Complete History of the World's Most Revolutionary Naval Weapon |url=https://books.google.com/books?id=Fk2uBQAAQBAJ&pg=PA157 |publisher=Seaforth Publishing |page=157 |isbn=978-1848322158 }}</ref>

===Proximity detonation===
A torpedo fitted with a proximity fuze can be detonated directly under the [[keel]] of a target ship. The explosion creates a gas bubble which may damage the keel or underside plating of the target. However, the most destructive part of the explosion is the upthrust of the gas bubble, which will bodily lift the hull in the water. The structure of the hull is designed to resist downward rather than upward pressure, causing severe strain in this phase of the explosion. When the gas bubble collapses, the hull will tend to fall into the void in the water, creating a sagging effect. Finally, the weakened hull will be hit by the uprush of water caused by the collapsing gas bubble, causing structural failure. On vessels up to the size of a modern [[frigate]], this can result in the ship breaking in two and sinking. This effect is likely to prove less catastrophic on a much larger hull, for instance, that of an [[aircraft carrier]].<ref name ="Branfill_Cook_2014"/>

===Damage===
The damage that may be caused by a torpedo depends on the "[[shock factor]] value", a combination of the initial strength of the explosion and the distance between the target and the detonation. For ship hull plating, the term "hull shock factor" (HSF) is used, while keel damage is termed "keel shock factor" (KSF). If the explosion is directly underneath the keel, then HSF is equal to KSF, but explosions that are not directly underneath the ship will have a lower value of KSF.<ref name=Reid1996/>

====Direct damage====
Usually only created by contact detonation, direct damage is a hole blown in the ship. Among the crew, [[Fragmentation (weaponry)|fragmentation]] wounds are the most common form of injury. Flooding typically occurs in one or two main watertight compartments, which can sink smaller ships or disable larger ones.

====Bubble-jet effect====
The bubble-jet effect occurs when a mine or torpedo detonates in the water a short distance away from the targeted ship. The explosion creates a bubble in the water, and due to the pressure difference, the bubble will collapse from the bottom. The bubble is buoyant, and so it rises towards the surface. If the bubble reaches the surface as it collapses, it can create a pillar of water that can go over a hundred meters into the air (a "columnar plume"). If conditions are right and the bubble collapses onto the ship's hull, the damage to the ship can be extremely serious; the collapsing bubble forms a high-energy jet that can break a meter-wide hole straight through the ship, flooding one or more compartments, and is capable of breaking smaller ships apart. The crew in the areas hit by the pillar are usually killed instantly. Other damage is usually limited.<ref name=Reid1996/>

The [[Baengnyeong incident]], in which {{ship|ROKS|Cheonan|PCC-772|6}} broke in half and sank off the coast South Korea in 2010, was caused by the bubble-jet effect, according to an international investigation.<ref>{{cite news |url=http://news.bbc.co.uk/nol/shared/bsp/hi/pdfs/20_05_10jigreport.pdf|title=Investigation Result on the Sinking of ROKS "Cheonan" by The Joint Civilian-Military Investigation Group|date=20 May 2010|access-date=27 January 2014|work=BBC News}}</ref><ref>{{cite news|url=https://www.nytimes.com/2010/04/26/world/asia/26korea.html|title=South Korea Cites Attack in Ship Sinking|newspaper=The New York Times|date=25 April 2010|access-date=25 April 2010 | first=Choe | last=Sang-Hun}}</ref>

====Shock effect====
If the torpedo detonates at a distance from the ship, and especially under the keel, the change in water pressure causes the ship to resonate. This is frequently the most deadly type of explosion if it is strong enough. The whole ship is dangerously shaken and everything on board is tossed around. Engines rip from their beds, cables from their holders, etc. A badly shaken ship usually sinks quickly, with hundreds or even thousands of small leaks all over the ship and no way to power the pumps. The crew fares no better, as the violent shaking tosses them around.<ref name=Reid1996>{{cite web |first=Warren D. |last=Reid |url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a326738.pdf |archive-url=https://web.archive.org/web/20200327122839/https://apps.dtic.mil/dtic/tr/fulltext/u2/a326738.pdf |url-status=live |archive-date=March 27, 2020 |title=The Response of Surface Ships to Underwater Explosions |id=DSTO-GD-0109 |date=September 1996 |publisher=Ship Structures and Materials Division, Aeronautical and Maritime Research Laboratory, Defence Science and Technology Organisation. Department of Defence}}</ref> This shaking is powerful enough to cause disabling injury to knees and other joints in the body, particularly if the affected person stands on surfaces connected directly to the hull (such as steel decks).

The resulting gas cavitation and [[shock-front]]-differential over the width of the human body is sufficient to stun or kill [[Frogman|divers]].<ref>{{cite report |author1=Cudahy, E |author2=Parvin, S |title=The Effects of Underwater Blast on Divers |series=US Naval Submarine Medical Research Lab Technical Report |id=NSMRL-1218 |year=2001 |url=http://archive.rubicon-foundation.org/7518 |access-date=2009-03-22 |archive-date=2009-07-03 |archive-url=https://web.archive.org/web/20090703203738/http://archive.rubicon-foundation.org/7518 |url-status=usurped }}</ref>

==Control surfaces and hydrodynamics==
Control surfaces are essential for a torpedo to maintain its course and depth. A homing torpedo also needs to be able to outmaneuver a target. Good hydrodynamics are needed for it to attain high speed efficiently and also to give a long range, since the torpedo has limited stored energy.

== Launch platforms and launchers ==
{{further|Torpedo tube}}
[[File: USN MK-46 Mod 5 lightweight torpedo.jpg|thumb|A [[Mark 32 Surface Vessel Torpedo Tubes|Mark 32 Mod 15 Surface Vessel Torpedo Tube]] (SVTT) fires a [[Mk 46 torpedo|Mark 46 Mod 5 lightweight torpedo]]]]

Torpedoes may be launched from submarines, surface ships, [[helicopter]]s, and fixed-wing [[aircraft]], unmanned [[naval mine]]s, and naval [[fortress]]es.<ref name="art museum">{{cite web|url=http://dartmouthmuseum.org/collections/memories/ww2.html|title=WW2 Memories – World War 2 – Second World War – Dartmouth Museum: Dartmouth Harbour was defended by Torpedo Tubes|publisher=[[Dartmouth Museum]]|access-date=2 April 2012|quote=Never fired in anger, a fixed torpedo tube battery was built on the east of the harbor mouth, just upriver from Kingswear Castle. The intent was to defend the river Dart.|url-status=dead|archive-url=http://arquivo.pt/wayback/20160518153630/http://dartmouthmuseum.org/collections/memories/ww2.html|archive-date=18 May 2016}}</ref> They are also used in conjunction with other weapons; for example, the [[Mark 46 torpedo]] used by the [[United States]] is the warhead section of the [[ASROC]], a kind of [[anti-submarine missile]]; the [[CAPTOR mine]] (CAPsulated TORpedo) is a submerged sensor platform which releases a torpedo when a hostile contact is detected.

===Ships===
[[File:Velos D16 amidships.JPG|thumb|Amidships quintuple mounting for {{convert|21|in|cm|abbr=on}} torpedoes aboard the World War II era destroyer {{USS|Charrette|DD-581|6}}]]

Originally, Whitehead torpedoes were intended for launch underwater and the firm was upset when they found out the British were launching them above water, as they considered their torpedoes too delicate for this. However, the torpedoes survived. The launch tubes could be fitted in a ship's bow, which weakened it for ramming, or on the broadside; this introduced problems because of water flow twisting the torpedo, so guide rails and sleeves were used to prevent it. The torpedoes were originally ejected from the tubes by compressed air, but later, slow-burning gunpowder was used. Torpedo boats originally used a frame that dropped the torpedo into the sea. Royal Navy [[Coastal Motor Boats]] of World War I used a rear-facing trough and a [[cordite]] ram to push the torpedoes into the water tail-first; they then had to move rapidly out of the way to avoid being hit by their torpedo.

Developed in the run-up to the first world war,{{citation needed|date=June 2012}} multiple-tube mounts (initially twin, later triple, and in the second world war up to quintuple in some ships) for {{convert|21|to|24|in|cm|abbr=on|adj=mid|order=flip}} torpedoes in rotating turntable mounts appeared. Destroyers could be found with two or three of these mounts with between five and twelve tubes in total. The Japanese went one better, covering their tube mounts with splinter protection and adding reloading gear (both unlike any other navy in the world),<ref>Fitzsimons, Bernard, ed. ''Illustrated Encyclopedia of Weapons and Warfare'' (London: Phoebus, 1978), Volume 10, p. 1040, "''Fubuki''"; Preston, Antony. ''Destroyers''.</ref> making them true turrets and increasing the broadside without adding tubes and [[top hamper]] (as the quadruple and quintuple mounts did). Considering that their [[Type 93 torpedo|Type 93s]] were very effective weapons, the IJN equipped their cruisers with torpedoes. The Germans also equipped their capital ships with torpedoes.

Smaller vessels such as PT boats carried their torpedoes in fixed deck-mounted tubes using compressed air. These were either aligned to fire forward or at an offset angle from the centerline.

Later, lightweight mounts for {{convert|12.75|in|cm|adj=mid|order=flip}} homing torpedoes were developed for anti-submarine use consisting of triple launch tubes used on the decks of ships. These were the 1960 [[Mk 32 torpedo launcher]] in the US and part of STWS (Shipborne Torpedo Weapon System) in the UK. Later, a below-decks launcher was used by the RN. This basic launch system continues to be used today with improved torpedoes and fire control systems.

===Submarines===
Modern submarines use either swim-out systems or a pulse of water to discharge the torpedo from the tube, both of which have the advantage of being significantly quieter than previous systems, helping avoid detection of the firing from passive sonar. Earlier designs used a pulse of compressed air or a hydraulic ram.

Early submarines, when they carried torpedoes, were fitted with a variety of torpedo launching mechanisms in a range of locations: on the deck, in the bow or stern, amidships, with some launch mechanisms permitting the torpedo to be aimed over a wide arc. By World War II, designs favored multiple bow tubes and fewer or no stern tubes. Modern submarine bows are usually occupied by a large sonar array, necessitating [[midships]] tubes angled outward, while stern tubes have largely disappeared. The first French and Russian submarines carried their torpedoes externally in [[Stefan Drzewiecki|Drzewiecki]] [[drop collar]]s. These were cheaper than tubes but less reliable. Both the United Kingdom and the United States experimented with external tubes in World War II. External tubes offered a cheap and easy way of increasing torpedo capacity without radical redesign, something neither had time or resources to do before nor early in, the war. [[British T-class submarine]]s carried up to 13 torpedo tubes, up to 5 of them external.  America's use was mainly limited to earlier [[United States Porpoise-class submarine|''Porpoise'']]-, {{sclass|Salmon|submarine|5}}-, and {{sclass|Sargo|submarine|5}}-class boats. Until the appearance of the {{sclass|Tambor|submarine|5}} class, most American submarines only carried 4 bow and either 2 or 4 stern tubes, something many American submarine officers felt provided inadequate firepower. {{citation needed|date=May 2013}} This problem was compounded by the notorious unreliability of the [[Mark 14 torpedo]].

Late in World War II, the U.S. adopted a {{convert|16|in|cm|adj=mid|order=flip}} homing torpedo (known as [[Mark 27 torpedo|"Cutie"]]) for use against escorts. It was basically a modified [[Mark 24 Mine]] with wooden rails to allow firing from a {{convert|21|in|cm|adj=mid|order=flip}} torpedo tube.{{sfn|Blair|1975|p={{page needed|date=January 2021}}}}<ref>{{cite book |first1=Charles A. |last1=Lockwood |first2=Hans C. |last2=Adamson |title=Hellcats of the Sea: Operation Barney and the Mission to the Sea of Japan |url=https://books.google.com/books?id=MBJtDwAAQBAJ |date=29 August 2018 |publisher=Lulu.com |isbn=978-0-359-05709-2}}</ref>

===Air launch===
{{Main|Aerial torpedo}}
[[Aerial torpedo]]es may be carried by fixed-wing aircraft, helicopters, or missiles. They are launched from the first two at prescribed speeds and altitudes, dropped from bomb-bays or underwing [[hardpoint]]s.

== Handling equipment ==
Although lightweight torpedoes are fairly easily handled, the transport and handling of heavyweight torpedoes is difficult, especially in the tight spaces in a submarine. After the Second World War, some Type XXI submarines were obtained from Germany by the United States and Britain. One of the main novel developments seen was a mechanical handling system for torpedoes. Such systems were widely adopted as a result of this discovery. {{citation needed|date=September 2014}}

== Classes and diameters ==
[[File:Argonaute FS S636 p1040844.jpg|thumb|Torpedo tube aboard the French submarine ''Argonaute'']]

Torpedoes are launched in several ways:
*From a [[torpedo tube]] mounted either in a trainable deck mount (common in [[destroyer]]s), or fixed above or below the waterline of a surface vessel (as in [[cruiser]]s, [[battleship]]s, and [[Auxiliary cruiser|armed merchant cruiser]]s) or [[submarine]].
*Early submarines and some [[torpedo boat]]s (such as the U.S. World War II [[PT boat]]s, which used the [[Mark 13 torpedo|Mark 13]] aircraft torpedo) used deck-mounted "[[drop collar]]s", which simply relied on gravity.
*From shackles aboard low-flying [[torpedo bomber|aircraft]] or [[helicopter]]s.
*As the final stage of a compound [[rocket]]- or [[ramjet]]-powered munition (sometimes called an ''assisted'' torpedo).

Many navies have two weights of torpedoes:
*A light torpedo used primarily as a close attack weapon, particularly by aircraft. The {{cvt|12.75|in|cm|adj=mid|order=flip}} caliber has been described as a NATO standard for this class.<ref>{{cite web |title=MU90 LIGHTWEIGHT TORPEDO |url=https://electronics.leonardo.com/documents/16277707/18402409/MU90.pdf?t=1671542549919 |website=electronics.leonardo.com}}</ref>
*A heavy torpedo used primarily as a standoff weapon, particularly by submerged submarines. The {{cvt|21|in|cm|adj=mid|order=flip}} caliber is a common standard.<ref name="Seahake_mod4">{{cite web |url= https://www.atlas-elektronik.com/fileadmin/user_upload/01_Images/Solutions/Datenblaetter_zum_Download/247_Seahake_mod4.pdf|title = SeaHake™ mod4
|publisher=Atlas Elektronik |access-date= 29 June 2024}}</ref>

In the case of deck- or tube-launched torpedoes, the diameter of the torpedo is a key factor in determining the suitability of a particular torpedo to a tube or launcher, similar to the [[caliber]] of the gun. The size is not quite as critical as for a gun, but the diameter has become the most common way of classifying torpedoes.

Length, weight, and other factors also contribute to compatibility. In the case of [[aircraft launched torpedo|aircraft-launched torpedo]]es, the key factors are weight, provision of suitable attachment points, and launch speed. Assisted torpedoes are the most recent development in torpedo design, and are normally engineered as an integrated package. Versions for aircraft and assisted launching have sometimes been based on deck or tube launched versions, and there has been at least one case of a submarine torpedo tube being designed to fire an aircraft torpedo.

As in all [[munition]] design, there is a compromise between standardization, which simplifies manufacture and [[logistics]], and specialization, which may make the weapon significantly more effective. Small improvements in either logistics or effectiveness can translate into enormous operational advantages.

== Use by various navies ==
{{Main|List of torpedoes}}

===List of active torpedoes by place of origin===
Modern heavyweight torpedoes are generally launched from submarines and are used to attack both surface ships and submarines. Relatively older heavyweight torpedoes were generally used to attack either surface ships or submarines. Modern lightweight torpedoes are launched from surface ships, helicopters, and fixed-wing aircraft and are used to attack submarines.

==== China ====
*Yu-11 torpedo (lightweight)
*[[Yu-7 torpedo]] (lightweight)
*[[Yu-6 torpedo]] (heavyweight)
*[[Yu-5 torpedo]] (heavyweight)
*[[Yu-4 torpedo]] (heavyweight)

====France====
[[File:MU90.jpg|thumb|right|[[MU90 Impact]] triple launcher onboard ''Hessen'', a {{sclass|Sachsen|frigate|1}} of the [[German Navy]].]]
*[[F21 (torpedo)|F21]] torpedo (heavyweight)
*[[F17 torpedo|F17]] torpedo (heavyweight) 
*[[MU90 Impact]] torpedo (lightweight)

====Germany====
[[File:Loading a SUT Torpedo into KRI Cakra 401.jpg|thumb|Loading of SUT Torpedo into Indonesian navy submarine, [[KRI Cakra (401)|KRI ''Cakra'' (401)]].]]
* Seadpider anti-torpedo (lightweight) (Atlas Elektronik)<ref>{{Cite web |date=2024-11-30 |title=Beschaffung von vier neuen U-Booten 212 CD für die Marine wird konkret |url=https://www.hartpunkt.de/beschaffung-von-vier-neuen-u-booten-212-cd-fuer-die-marine-wird-konkret/ |access-date=2024-11-30 |language=de}}</ref>
* [[DM2A4]] torpedo (heavyweight)
* DM2A3 torpedo (heavyweight)
* [[SUT torpedo]] (heavyweight)

====India====
[[File:Varunastra.jpg|thumb|Varunastra heavyweight torpedo]]
* [[Varunastra (Torpedo)|Varunastra]]  (surface and submarine launched heavyweight torpedo)<ref>{{Cite web|last=Kumar|first=V. Rishi|title=DRDO flags off first Varunastra, a heavy weight torpedo|url=https://www.thehindubusinessline.com/news/drdo-flags-off-first-varunastra-a-heavy-weight-torpedo/article33150441.ece|access-date=2021-09-30|website=@businessline| date=21 November 2020 |language=en}}</ref>
* [[Takshak torpedo|Takshak]] torpedo (heavyweight)<ref>{{Cite web|last=SUBRAMANIAN|first=T. S.|title=Underwater might|url=https://frontline.thehindu.com/other/article30164828.ece|access-date=2021-09-30|website=Frontline|language=en|archive-date=2021-09-28|archive-url=https://web.archive.org/web/20210928105811/https://frontline.thehindu.com/other/article30164828.ece|url-status=dead}}</ref>
* [[Torpedo Advanced Light Shyena]]<ref>{{Cite news|last=Bhattacharjee|first=Sumit|date=2021-03-09|title=Lightweight torpedo test-fired successfully|language=en-IN|work=The Hindu|url=https://www.thehindu.com/news/national/andhra-pradesh/lightweight-torpedo-test-fired-successfully/article34022882.ece|access-date=2021-09-30|issn=0971-751X}}</ref> (lightweight)

====Iran====
[[File:Torpille Valfajr.jpg|thumb|[[Valfajr (torpedo)|Valfajr]] heavyweight torpedo]]
* [[Valfajr (torpedo)|Valfajr torpedo]] (heavyweight)  
* [[Hoot (torpedo)|Hoot]] supercavitation torpedo (heavyweight)

====Italy====
* [[A184 torpedo|A184]] torpedo (heavyweight)
* [[A244-S|A244/S]] torpedo (lightweight)
* [[MU90 Impact]] torpedo (lightweight)
* [[A200 LCAW torpedo|A200 LCAW]] torpedo (miniature)
* [[Black Shark torpedo|Black Shark]] torpedo (heavyweight)
* [[Black Arrow torpedo|Black Arrow]] torpedo (lightweight)
* [[Black Scorpion torpedo|Black Scorpion]] torpedo (miniature)

====Japan====
* [[Japanese 53 cm torpedo#Type 80|Type 80 (G-RX1)]] torpedo (heavyweight)
* [[Type 89 torpedo|Type 89 (G-RX2)]] torpedo (heavyweight)
* [[Type 97 light weight torpedo (G-RX4)|Type 97 (G-RX4)]] torpedo (lightweight)
* [[Type 12 torpedo|Type 12 (G-RX5)]] torpedo (lightweight)
* [[Japanese 53 cm torpedo#Type 18|Type 18 (G-RX6)]] torpedo (heavyweight)

====Pakistan====
* [[Eghraaq]]

====Russia====
[[File:Shkval.jpg|thumb|VA-111 Shkval [[supercavitating torpedo]]]]
* [[Status-6 Oceanic Multipurpose System]] (nuclear-powered, nuclear-armed [[Unmanned underwater vehicle|UUV]])
* [[Futlyar]] (Fizik-2) (heavyweight)
* [[Type 53 torpedo]] family including Fizik (UGST), USET-80 (heavyweight)
* TEST 71/76 torpedo (heavyweight)
* [[VA-111 Shkval torpedo|VA-111 Shkval]] supercavitation torpedo (heavyweight)
* [[Type 65 torpedo]] (heavyweight)<ref>{{Cite web | url=https://ria.ru/arms/20180325/1517217656.html |title = Российский "Кит" может в одиночку потопить вражеский авианосец|date = 25 March 2018}}</ref>
* [[APR-3E torpedo]] (lightweight)
* APR-2 torpedo (lightweight)
In April 2015, the ''Fizik'' ([[Type 53 torpedo|UGST]]) heat-seeking torpedo entered service to replace the wake-homing USET-80 developed in the 1980s,<ref name="TASS">{{Cite web|url=http://tass.com/defense/883900|title=Russian Navy to receive advanced Futlyar torpedoes|website=TASS}}</ref><ref>{{Cite web|url=http://www.navweaps.com/Weapons/WTRussian_post-WWII.php|title=Post-World War II Torpedoes of Russia/USSR - NavWeaps|website=www.navweaps.com}}</ref> and the next-gen [[Futlyar]] entered service in 2017.<ref name="DW">{{Cite web|url=https://www.defenseworld.net/news/18680/Russian_Navy_To_Commission_Latest_Deep_Water_Torpedo__Futlyar__In_2018|title=Russian Navy To Commission Latest Deep-Water Torpedo 'Futlyar' In 2018|website=www.defenseworld.net}}</ref><ref name="TASS"/><ref name="NR">{{Cite web | url=http://www.navyrecognition.com/index.php/news/defence-news/2017/march-2017-navy-naval-forces-defense-industry-technology-maritime-security-global-news/4995-improved-ugst-fizik-torpedo-futlyar-to-enter-russian-navy-service-in-2018.html | title=Improved UGST / Fizik Torpedo| date=16 March 2017}}</ref>

====Republic of Korea====
[[File:2023-05-12 AW159 Wildcat 003.jpg|thumb|[[AgustaWestland AW159 Wildcat|AW159 Wildcat]] helicopter of the Philippine Navy armed with  [[K745 Blue Shark]] torpedoes taken at the Philippine Fleet Defense Expo (PFDX) 2023]]
* [[K731 White Shark]] torpedo (heavyweight)
* [[K745 Blue Shark]] torpedo (lightweight)
* [[K761 Tiger Shark]] torpedo (heavyweight)

==== Sweden ====
*[[Torped 613]] (heavyweight)
*[[Torped 62]] (heavyweight)
*[[Torped 47]] (lightweight)
*[[Torped 45]] (lightweight)

==== Turkey ====
*[[Roketsan Akya]] torpedo (heavyweight) 
*[[Roketsan Orka]] torpedo (lightweight)

====United Kingdom====
* [[Spearfish torpedo]] (heavyweight)
* [[Mark 24 Tigerfish|Tigerfish]] torpedo (heavyweight)
* [[Sting Ray (torpedo)|Sting Ray]] torpedo (lightweight)

====United States of America====
[[File:Lynx mk46.jpg|thumb|A French [[Lynx (helicopter)|Lynx]] helicopter carrying a [[Mark 46 torpedo]]]]
* [[Mark 54 LHT|Mark 54 torpedo]] (lightweight)
* [[Mark 50 torpedo]] (lightweight)
* [[Mark 48 torpedo]] (heavyweight)
* [[Mark 46 torpedo]] (lightweight)

===List of key WWII torpedoes===
The torpedoes used by the [[Imperial Japanese Navy]] (World War II) included:
* [[Japanese 53 cm torpedo|Japanese 53 cm]] torpedoes (up to Type 96); Type 89, Type 95, Type 96 most significant
* [[Japanese 45 cm torpedo|Japanese 45 cm]] torpedoes; Type 44, Type 91, Type 97/98 most significant
* [[Japanese 61 cm torpedo|Japanese 61 cm]] torpedoes; Type 90, Type 93 most significant
* [[Type 91 torpedo]]
* [[Type 92 torpedo]]
* [[Type 93 torpedo]] (Long Lance)
* [[Type 95 torpedo]]
* [[Type 97 torpedo]]
* [[Kaiten]]

The torpedoes used by the World War II [[Kriegsmarine]] included:
* [[G7a torpedo|G7a(TI)]]
* [[G7e torpedo#G7e(TII)|G7e(TII)]]
* [[G7e torpedo#G7e(TIII)|G7e(TIII)]]
* [[G7e torpedo#G7es(TIV) Falke|G7es(TIV) "Falke"]]
* [[G7es torpedo|G7es(TV) "Zaunkönig"]]

The torpedoes used by the World War II [[Royal Navy]] included:
* [[British 21-inch torpedo|British 21-inch]] torpedoes (up to Mark XI); [[British 21-inch torpedo#Mark VIII|Mark VIII]] and [[British 21-inch torpedo#Mark IX|Mark IX]] most significant
* [[British 18-inch torpedo|British 18-inch]] torpedoes (up to Mark XVII); [[British 18-inch torpedo#Mark XII|Mark XII]] and [[British 18-inch torpedo#Mark XV|Mark XV]] most significant

The torpedoes used by the World War II [[United States Navy]] included:
*[[Mark 18 torpedo]]
*[[Mark 15 torpedo]]
*[[Mark 14 torpedo]]

==See also==
* [[Anti-submarine weapon]]
* [[Autonomous Underwater Vehicle]]
* [[Bangalore torpedo]]
* [[Human torpedo]]
* [[List of torpedoes]]
* [[Missile guidance]]
* [[Nuclear torpedo]]
* [[André Rebouças]], who supposedly developed a torpedo in the [[Paraguayan War]] (1864–1870)
* [[Shock factor]]
* [[Torpedo defence]]
* [[Unmanned underwater vehicle]]

==References==
'''Notes'''
{{reflist}}

'''Bibliography'''
* {{cite book |first=Clay |last=Blair |title=Silent Victory: The U.S. Submarine War Against Japan |url=https://books.google.com/books?id=wa0NAQAAMAAJ |year=1975 |publisher=Lippincott |isbn=978-0-397-00753-0}}
* {{cite book |first=Walter J. |last=Boyne |title=Clash of Titans |publisher=Simon and Schuster |year=1995 |isbn=0-684-80196-5 }}
* {{cite book |first=David |last=Brown |title=Warship Losses of World War Two |publisher=Arms and Armour |year=1990 |isbn=0-85368-802-8 }}
* ''The Columbia Encyclopedia'', Sixth Edition, online.
* {{cite journal |first=R. O. |last=Crowley |title=Confederate Torpedo Service |journal=[[The Century Magazine|The Century]] |volume=56 |issue=2 |date=June 1898 |publisher=[[The Century Company]]}}
* {{cite book |first=James |last=Davey |title=In Nelson's Wake |publisher=Yale University Press |year=2016 |isbn=978-0300200652 }}
* {{cite book |first=Katherine C. |last=Epstein |title=Torpedo |url=https://books.google.com/books?id=cay-AQAAQBAJ |date=2014 |publisher=Harvard University Press |isbn=978-0-674-72740-3}}
* {{cite journal |last1=Gibbs |first1=Jay |title=Question 25/00: Defective Torpedoes of WW II|journal=Warship International |date=2001 |volume=XXXVIII |issue=4 |pages=328–329 |issn=0043-0374}}
* {{cite book |first=Edwyn |last=Gray |title=The Devil's Device: The story of Robert Whitehead, Inventor of the Torpedo |publisher=Seeley |year=1975 |isbn=978-0-85422-104-2 }}
* {{cite book |first=Edwyn |last=Gray |title=Nineteenth-Century Torpedoes and Their Inventors |publisher=US Naval Institute Press |year=2004 |isbn=978-1-59114-341-3 |url=https://books.google.com/books?id=jaaHQ4FlKS4C}}
* {{cite book |first=David |last=Lyon |title=The First Destroyers |publisher=Chatham |year=1996 |isbn=1-55750-271-4 }}
* {{cite journal |first=Frederick J. |last=Milford |title=U.S. Navy Torpedoes: Part One—Torpedoes through the Thirties |journal=The Submarine Review |date=April 1996 |publisher=Naval Submarine League |location=Annandale, VA |oclc=938396939}}
* {{cite journal |first=Frederick J. |last=Milford |title=U.S. Navy Torpedoes: Part Two—The Great Torpedo Scandal, 1941–43 |journal=The Submarine Review |date=October 1996 }}
* {{cite journal |first=Frederick J. |last=Milford |title=U.S. Navy Torpedoes: Part Three—WW II development of conventional torpedoes 1940–1946 |journal=The Submarine Review |date=January 1997 }}
* {{cite book |last=Morison |first=Samuel Eliot |author-link=Samuel Eliot Morison |series=History of United States Naval Operations in World War II |title=The rising sun in the Pacific, 1931–April 1942 |volume=3 |url=https://books.google.com/books?id=piEUmkf8o_cC |year=2001 |publisher=University of Illinois Press |isbn=978-0-252-06973-4 |orig-year=1948}}
* {{cite book |first=Richard |last=O'Kane |title=Wahoo: The Patrols of America's Most Famous World War II Submarine |url=https://books.google.com/books?id=gWF-qw7RH8kC |date=2009 |publisher=Random House |isbn=978-0-307-54884-9 |orig-year=1987}}
* {{cite book |first=Piotr |last=Olender |title=Battle of Tsushima |series=Russo-Japanese Naval War 1904–1905 |volume=2 |publisher=Stratus s.c. |location=Sandomierz, Poland |year=2010 |isbn=978-83-61421-02-3 }}
* {{cite book |first=Milton F. |last=Perry |title=Infernal Machines: The Story of Confederate Submarine and Mine Warfare |publisher=Louisiana State University Press |year=1985 |isbn=0-8071-1285-2 }}
; Attribution
* {{PD-old-text|title=Overland monthly and Out West magazine|year=1886|author=Bret Harte}}

==External links==
{{Commons category|Torpedoes}}
* [https://web.archive.org/web/20120222222226/http://www.bharat-rakshak.com/MONITOR/ISSUE3-4/joseph.html "Modern Torpedoes And Countermeasures"], by Austin Joseph, ''Bharat Rakshak Monitor'', Volume 3(4) January–February 2001.
* [https://web.archive.org/web/20051104005915/http://www.chinfo.navy.mil/navpalib/factfile/weapons/wep-torp.html Navy Fact File Torpedoes: Mark 46, Mark 48, Mark 50], the source of the US Navy torpedo data (via the [[Internet Archive]])
* [http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=900&ct=2 The US Navy – Fact File: Torpedo – Mark 46] {{Webarchive|url=https://web.archive.org/web/20190320025704/https://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=900&ct=2 |date=2019-03-20 }}
* [http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=950&ct=2 The US Navy – Fact File: Heavyweight Torpedo – Mark 48] {{Webarchive|url=https://web.archive.org/web/20200702202236/http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=950&ct=2 |date=2020-07-02 }}
* [http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=1000&ct=2 The US Navy – Fact File: Torpedo – Mark 50] {{Webarchive|url=https://web.archive.org/web/20200702084355/http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=1000&ct=2 |date=2020-07-02 }}
* [http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=1100&ct=2 The US Navy – Fact File: Torpedo – Mark 54] {{Webarchive|url=https://web.archive.org/web/20130513045055/http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=1100&ct=2 |date=2013-05-13 }}
* [https://archive.today/20120530070555/http://www.btinternet.com/~philipr/torps.htm "A History of the Torpedo The Early Days"]
* [http://www.geoffkirby.co.uk/TorpedoHistory1972.doc "Torpedo History" Geoff Kirby (1972)] {{Webarchive|url=https://web.archive.org/web/20201021040443/http://www.geoffkirby.co.uk/TorpedoHistory1972.doc |date=2020-10-21 }}
* [http://www.geoffkirby.co.uk/rocket-torpedoes.pdf "Development of Rocket Torpedoes" Geoff Kirby (2000)] {{Webarchive|url=https://web.archive.org/web/20201108092414/http://www.geoffkirby.co.uk/rocket-torpedoes.pdf |date=2020-11-08 }}
* [https://web.archive.org/web/20050908111923/http://www.keyportmuseum.cnrnw.navy.mil/torpedotech.htm Torpedo Display], US Naval Undersea Museum
* [https://web.archive.org/web/20050226023752/http://www.keyportmuseum.cnrnw.navy.mil/torpedoes.htm Torpedo Collection], US Naval Undersea Museum
* [http://www.diehl-bgt.de/index.php?id=550&L=1 Super Cavitation Torpedo 'Barracuda'] {{Webarchive|url=https://web.archive.org/web/20090416213806/http://www.diehl-bgt.de/index.php?id=550&L=1 |date=2009-04-16 }}
* [https://web.archive.org/web/20130527115531/http://www.scientificamericanpast.com/Scientific%20American%201890%20to%201899/1/lg/sci7261890.htm 1890-07-26: THE SIMS – EDISON ELECTRIC TORPEDO – THE TORPEDO AT FULL SPEED – SECTIONAL VIEW OF THE TORPEDO]
* [https://books.google.com/books?id=WicDAAAAMBAJ&pg=PA94 "Our New Torpedo Bombers to Batter the Axis"], ''[[Popular Science]]'', September 1942; illustration at bottom of page 94 shows how Whitehead's so-called "secret unit" (i.e., the Pendulum mechanism) kept a torpedo level after entering the water, which made the self-propelled torpedo possible
* [https://books.google.com/books?id=PN8DAAAAMBAJ&pg=RA1-PA50 "Torture Test for Tin Fishes"]—August 1944 ''[[Popular Mechanics]]'' article on testing US torpedoes – detailed photos

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[[Category:Torpedoes| ]]