While the 19th-century battleship had evolved primarily with a view to engagements between armored warships with large-caliber guns, the invention and refinement of torpedoes from the 1860s onwards allowed small torpedo boats and other lighter surface vessels, submarines/submersibles, even improvised fishing boats 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.
For example, in 1275, engineer Hasan al-Rammah – who worked as a military scientist for the Mamluk Sultanate of Egypt – wrote that it might be possible to create a projectile resembling "an egg", which propelled itself through water, whilst carrying "fire".
During the war, American forces unsuccessfully attempted to destroy the British ship of the line 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".
During the American Civil War, the term torpedo was used for what is today called a contact mine, floating on or below the water surface using an air-filled demijohn or similar flotation device.
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.
[14][15] 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.
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.
[17] Whitehead opened a new factory adjacent to Portland Harbour, England, in 1890, which continued making torpedoes until the end of World War II.
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.
[20] The Royal Navy frigate HMS Shah was the first naval vessel to fire a self-propelled torpedo in anger during the Battle of Pacocha against rebel Peruvian ironclad Huáscar on 29 May 1877.
[25] 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.
[33] Awarded a patent in 1912,[34][35] 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.
[38] On 12 August 1915 one of these, piloted by Flight Commander Charles Edmonds, was the first aircraft in the world to attack an enemy ship with an air-launched torpedo.
Only the British and Japanese had fully tested new technologies for torpedoes (in particular the Type 93, nicknamed Long Lance postwar by the US official historian Samuel E. Morison)[42][43] at the start of World War II.
[44] The Type 91 had an advanced PID controller and jettisonable, wooden Kyoban aerial stabilizing surfaces which released upon entering the water, making it a formidable anti-ship weapon; Nazi Germany considered manufacturing it as the Luftorpedo LT 850 after August 1942.
[45] The Royal Navy's 24.5-inch oxygen-enriched air torpedo saw service in the two Nelson class battleships although by World War II the use of enriched oxygen had been discontinued due to safety concerns.
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 pistols 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.
Both the Navy Bureau of Ordnance and the United States Congress were too busy protecting their interests to correct the errors, and fully functioning torpedoes only became available to the USN twenty-one months into the Pacific War.
In the Battle off Samar, destroyer torpedoes from the escorts of the American task force "Taffy 3" showed effectiveness at defeating armor.
During World War II, Hedy Lamarr and composer George Antheil developed a radio guidance system for Allied torpedoes, it intended to use frequency-hopping technology to defeat the threat of jamming by the Axis powers.
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.
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 93s.
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,[70] this was a hit or miss proposition, even when everything worked correctly) and, through gyroscopes, a straight course.
In World War II the Germans introduced programmable pattern-running torpedoes, which would run a predetermined pattern until they either ran out of fuel or hit something.
[79] 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 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.
Later, lightweight mounts for 12.75 in (32.4 cm) homing torpedoes were developed for anti-submarine use consisting of triple launch tubes used on the decks of ships.
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.