Torpedo

A modern torpedo, historically called a locomotive torpedo, is a self-propelled projectile that (after being launched above or below the water surface) operates underwater and is designed to detonate on contact or in proximity to a target. Torpedoes are weapons that may be launched from submarines, surface ships, helicopters and fixed-wing aircraft, unmanned naval mines and naval fortresses.

A Mark-32 Mod 15 Surface Vessel Torpedo Tube (SVTT) fires a Mark-46 Mod 5 lightweight torpedo.

They are also used as parts of other weapons; the Mark 46 torpedo used by the United States becomes the warhead section of the ASROC (Anti-Submarine ROCket) and the Captor mine uses a submerged sensor platform that releases a torpedo when a hostile contact is detected.

Etymology

Torpedo.Plymouth.NavyAndArmyIllustrated.jpg.jpg

A Torpedo Exercise in Plymouth.

The word torpedo comes from the torpedo genus of electric rays in the order Torpediniformes, which in turn comes from the Latin "torpere" to stun. There is no physical resemblance between the ray and the mechanical torpedo. In naval usage, the term "torpedo" was used by Robert Fulton who used the word for the towed gunpowder charge used by his submarine Nautilus in 1800–1805 to demonstrate that it could sink warships.

During the American Civil War a "torpedo" was usually a "contact mine" above water using a "demijohn" or a similar container that would float, and below water tethered to the bottom using a line and a weight holding the contact mine just below the surface to sink a ship. Former USN Commander Matthew Fontaine Maury, a Virginian who ended up as a Commander in the Confederacy when Virginia (after Fort Sumter) and three other states joined the Confederacy due to Lincoln's call for 75,000 troops to march on the South. Maury worked with underwater electrical "torpedoes" having worked with electricity under the sea in the laying of the Atlantic Cable aiding Cyrus West Field (August 1858 1st success from USA to Europe).

The torpedo room of Argonaute, a Cold War-era French Diesel submarine.

Tethered and floating contact mines are what David Farragut encountered in 1864 at the Battle of Mobile Bay during the American Civil War. After the leading ironclad, USS Tecumseh, was sunk by a tethered contact mine (torpedo). His vessels halted, afraid of hitting additional torpedoes, but inspiring his men to push forward, Farragut famously yelled, "damn the torpedoes, full speed ahead!"

As self-propelled torpedoes were developed the tethered variety was referred to as "stationary torpedo" and later "contact mine." There were also land "contact mines" used by Confederate General Rains with great success and used by others elsewhere throughout the Civil War. Contact mines are still used to-date. True "torpedos" owe their creation to the mid-1800's British engineer Robert Whitehead.

The Bangalore Torpedo, invented in 1912, is a cylindrical explosive device on the end of a pipe used to clear minefields and barbed wire. As such it can be considered a land form of the spar torpedo.

History

Prior to the invention of the self-propelled naval torpedo, the term "torpedo" was applied to any number of different types of explosive devices, generally having the property of being secret or hidden, including devices we would today call booby traps, land mines and naval mines, among others.

Early Naval Torpedoes

Although the term "torpedo" was not coined until 1800, the early submarine Turtle attacked using an explosive very similar in intent and operation to Fulton's "torpedoes." The "Turtle" would dive under a British vessel and attach a bomb by means of an augur. The bomb was detonated by a timed fuze, probably a type of clockwork mechanism. In its only recorded attack, the "Turtle" failed to penetrate the hull of the HMS Eagle, which had been copper-plated to resist the action of marine worms.

The first usage of the term "torpedo" to refer to a naval explosive was by the inventor Robert Fulton who used the word for the towed gunpowder charge used by his submarine Nautilus in 1800–1805 to demonstrate that it could sink warships. This type of towed torpedo, fitted with one of several types of contact fuzes, remained in use through the American Civil War. The Confederate submarine H. L. Hunley was originally designed to use this type of torpedo.

Confederates sinking torpedoes in Charleston Harbor

The Civil War saw the deployment of several types of naval torpedo, most often by the Confederates, who faced a severe disadvantage in more traditional warfare methods. The simplest were floating torpedoes with contact or timed fuzes, set adrift to attack enemy forces downriver. They were, as to be expected, highly unreliable. Several types of moored underwater torpedoes were manufactured by filling waterproof kegs, casks and demijohns with gunpowder and attaching contact fuzes. These could be as much a danger to Confederate as to Union shipping, and were sometimes marked with flags, that could be removed if Union attack was deemed imminent. Rivers that had been mined with Confederate torpedoes were often cleared by the simple expedient of placing captured Confederate soldiers with knowledge of the torpedoes' location in small boats ahead of the main fleet.

Illustration of naval torpedoes moored to the river bottom (the predecessors of modern naval mines)

Electrically-detonated underwater torpedoes were also employed. These had the advantage of being controlled by an operator on shore, so that friendly vessels or low-value enemy vessels could be ignored while waiting for the capital ships to sail over them. However, the Confederacy was plagued by a chronic shortage of materials including platinum and copper wire and acid for batteries, and the wires had a tendency to break.

The first torpedoes driven at specific targets were spar torpedoes; the explosive device was on the end of a spar up to 40 feet long projecting forward under water from the bow of the attacking vessel. When driven up against the enemy and detonated, a hole would be caused below the water line. Spar torpedoes were employed by the Confederate submarine H. L. Hunley and the David class of torpedo boats, among others.

The first real torpedo was developed in the mid 1800's in Europe by Mr Robert Whitehead, who created the "Whitehead Torpedo", used by 30 navies by the First World War.

Bombs and Booby Traps

During the Civil War, the term "torpedo" was also used to refer to various types of bombs and booby traps. Confederate General Gabriel Rains deployed "sub-terra shells" or "land torpedoes", artillery shells with pressure-sensitive fuzes buried in the road by retreating Confederate forces to delay their pursuers. These were the forerunners of modern land mines. Although Union generals publicly deplored this conduct, General Sherman employed the same technique on his March to the Sea.

Confederate secret agent John Maxwell used a clockwork mechanism to detonate a large "horological torpedo" (time bomb) on August 9, 1864. The bomb was hidden in a box marked "candles" and placed aboard a barge containing Union ammunition—20,000-30,000 artillery shells and 75,000 rounds of small arms ammunition—that was moored at City Point, Virginia, on the James River. The explosion caused more than $2 million in damage and killed at least 43 people.

The coal torpedo was a bomb shaped like a lump of coal, to be hidden in coal piles used for fueling Union Naval Vessels. The bomb would be shoveled into the firebox along with the real coal, causing an explosion. Although the North referred to the device as the coal torpedo in newspaper articles, the Confederates referred to it as a "coal shell."

Self-Propelled Torpedoes

A torpedo dropped from a Sopwith Cuckoo during WWI.

Narrow miss by a German torpedo in WWI.

WWI Austrian battleship with torpedo nets.

Arabs are known to have what could be described as Torpedoes as early as the 15th Century. Records tell of a self-propelled pear shaped bomb with a spear at the front which impaled itself in the enemy ships and then blew up.[1]

The first European prototypes of a self-propelled torpedo were created by Giovanni Lupis, a retired naval engineer from the port city of Fiume/Rijeka (today Rijeka) who served in the Austro-Hungarian Navy. The design was presented to the Emperor Franz Joseph in 1860. Robert Whitehead, an English engineer/entrepreneur, was working in the Trieste port on navy projects, so in 1864 Lupis made a contract with him in order to perfect the invention. This resulted in Minenschiff, the first self-propelled torpedo, officially presented to the Imperial Naval commission on December 21, 1866.

After the government decided to invest in the invention, Whitehead started the first torpedo factory in Fiume. In 1870, they improved the devices to travel up to 1,000 yards (914 m) at a speed of up to six knots, and by 1881 the factory was exporting its torpedoes to ten other countries. The torpedo was powered by compressed air and had an explosive charge of gloxyline or gun-cotton. Whitehead went on to develop more efficient devices, demonstrating torpedoes capable of 18 knots (1876), 24 knots (1886) and finally 30 knots (1890).

Whitehead purchased rights to the gyroscope in 1890 to improve self-regulation of his designs. Whitehead's torpedoes came to be called the Devil's device.

In 1877 the British Admiralty paid him £15,000 for certain of his developments and he opened a new factory near Portland harbour in 1891. The largest Whitehead torpedo was an 18 inch (457mm) model, 19 feet (5.8 m) long, made of polished steel or phosphor-bronze, with a 200 lb (90 kg) gun-cotton warhead. The air was compressed to around 1,300 lb/in² (approx 90 atmospheres) and drove two propellers through a three cylinder Brotherhood engine. Considerable effort was taken in trying to ensure that the torpedo self-regulated its course and depth.

On 16 January 1877, Turkish steamer Intibah became the first vessel to be sunk by torpedoes, launched from torpedo boats operating from the tender Velikiy Knyaz Konstantin under the command of Stepan Osipovich Makarov during the Russo-Turkish War of 1877-78.

In another early use of the torpedo, Blanco Encalada was sunk by a torpedo from the gunboat Almirante Lynch, during the Chilean Civil War on April 23 1891.

By this time, the torpedo boat had gained recognition for its efficiency, and the first torpedo boat destroyers were built to counter it. Torpedoes were also used to equip gunboats making them torpedo gunboats, ships of around 1,000 tons displacment.

Around 1897, Nikola Tesla patented a remote controlled boat and later demonstrated the feasibility of radio-guided torpedoes to the United States military. Radio remote controlled torpedoes remained uninvestigated until the 1960s.

During World War I, torpedoes came to mean self-propelled projectiles fired from a ship or submarine. Later, torpedoes were given (homing) guidance systems.

In the inter-war years, tight budgets in nearly all navies caused them to skimp on testing their torpedoes. As a result, only the Japanese had fully-tested torpedoes at the start of the Second World War. All classes of ship from destroyers to battleships were armed with torpedoes.

The strategic thinking of all major navies was, enemy capital ships (warships) would be the primary targets of submarines, in a classic fleet action on the high seas. This was in keeping with the theory of Alfred Thayer Mahan, dominant in naval thinking at that time. Targeting enemy merchant shipping was prohibited by rules of war. Due to the heavy armor of enemy warships, there was concern torpedoes would be ineffective. The potential solution to this was a magnetic exploder which would cause the torpedoes to detonate beneath a ship, breaking its back. This had been demonstrated by magnetic influence mines in World War One. (In principle, this was correct; modern torpedoes function in this manner. An explosion below a ship causes the formation of a gas bubble, and the unsupported hull splits and falls into it.) This requires the torpedo be set to run beneath the ship, and the magnetic exploder to activate at the correct time. Germany, Britain, and the U.S. had 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 earth's magnetic field on ships and exploder mechanisms, which resulted in premature detonation, while underruns produced duds, and concealed flaws. Kriegsmarine responded promptly in isolating and eliminating the problems. The Royal Navy cleared up their faults as well. In the United States Navy (USN) there was an extended wrangle over the issue. One design flaw had concealed another. Cursory trials had allowed bad designs to enter service. Turf protection in both the Navy and Congress prevented the mistakes from being corrected. It was twenty months into the Pacific War before fully-functioning torpedoes were issued, adding months to the duration of the war.

Propulsion

Compressed air

This first, successful, self-propelled torpedo of 1866 used compressed air as its energy source. The air was stored at pressures of up to 2.55 MPa and fed to a piston engine which turned a single propeller at about 100 rpm. It was able to travel about 180 metres at an average speed of 6.5 knots. The speed and range of later models was enhanced by increasing the pressure of the stored air. In 1906 Whitehead built torpedoes which were able to travel nearly 1000 metres at an average speed of 35 kts.

At higher pressures the cooling experienced by the air as it expanded in the engine caused icing problems (see adiabatic cooling). This was remedied by heating the air with seawater before it was fed to the engine. Unexpectedly, this increased engine performance further, because the air expanded even more after heating.

Heated torpedoes

This led to the idea of injecting a liquid fuel, like kerosene, into the air and igniting it. In this manner the air is heated up more and expands even further, and the burned propellant adds more gas to drive the engine. Construction of such heated torpedoes started around 1904.

Wet-heater

A further enhancement to this design was the use of water to cool the combustion chamber. This not only solved heating problems so that more fuel could be burnt, but it 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 torpedoes without steam generation were, retrospectively, called dry heaters. Most torpedoes used in World War I and World War II were wet-heaters.

Compressed oxygen

The amount of fuel that can be burnt by a torpedo engine is limited by the amount of oxygen it can carry. Since compressed air contains only about 21% of oxygen, engineers in Japan developed the Type 93 torpedo (nicknamed long lance postwar by historian Samuel E. Morison) for destroyers in the 1930s, which used pure oxygen instead of compressed air and had an unmatched performance in World War II.

Steam

A derivative of the compressed-air torpedo was the steam driven torpedo. It had to be fuelled with superheated steam from the boilers of the attacking vessel prior to launch. This was a disadvantage since it couldn't be stored ready to use.

Wire driven

The Brennan Torpedo had two wires wound around drums inside the torpedo. A shore based steam powered winch pulled the wires which spun the drums and drove the propeller. Such systems had been in use for coastal defence of the British homeland and colonies from 1887 to 1903. Speed was about 25 knots for over 2,400 m.

Flywheel

Another source of mechanical energy is a flywheel. The Howell torpedo in use with the US Navy of the late 1800s featured a heavy flywheel which had to be spun up before launch. It was able to travel about 750m with an average speed of 30knts. The advantage of the Howell torpedo was that it didn't leave a trail of bubbles behind it like compressed air torpedoes, giving the target less chance to detect and evade the torpedo. It also avoided giving away the attacker's position.

Electric propulsions

For the same reasons, designers pursued the development of an electric propulsion system for torpedoes. in 1873 John Ericsson invented a torpedo that was cable-powered by an external source, as electric batteries of that time didn't offer enough capacity for useful range and speed figures.

Germany was the first nation to field an electric torpedo shortly prior World War II, the G7e. It was slower and of shorter range than its conventional G7a counterpart, but wakeless and much cheaper to produce. On the other hand, it used a lead-acid rechargeable battery which was sensitive to shock and also required frequent maintenance and needed to be preheated for best performance before launch. To overcome these restrictions, other energy sources were researched.

The experimental G7ep, an enhancement of the G7e, used primary cells like modern electric torpedoes. Silver-oxide is the most common type of batteries in post-war electric torpedoes like the Mark 24 Tigerfish or DM2 series. Such a battery needs no maintenance and a torpedo equipped with it can be shelved for years without losing much performance.

Modern propulsion systems

Modern torpedoes utilize a variety of energy sources that include gas turbines (the British Spearfish torpedo), monopropellants and sulphur hexafluoride gas sprayed over a block of solid lithium. Some torpedoes such as the Russian VA-111 Shkval also use supercavitation to increase their speed to over 200 knots (370 km/h); compare e.g. the speed of the Mark 46 torpedo: > 28 knots (32 mi/h, 52 km/h).

Torpedo classes and diameters

Torpedo tube aboard the French submarine Argonaute

Torpedoes are launched several ways:
*From a deck-mounted "drop collar" (such as those on U.S. PT boats in WW2)
*From a torpedo tube mounted either in a trainable deck mount (common in destroyers) or fixed (above or below the waterline of a surface vessel (as in cruisers, battleships, and armed merchant cruisers), or aboard a submarine.
*From shackles aboard low-flying aircraft or helicopters.
*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.
*A heavy torpedo used primarily as a standoff weapon, particularly by submerged submarines.

In the case of deck or tube launched torpedoes, the diameter of the torpedo is obviously 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 barrel, but diameter has become the most common way of classifying torpedoes.

Test firing of the Mark 48 torpedo by the Australian Navy on Torrens

Length, weight, and other factors also contribute to compatibility. In the case of aircraft launched torpedoes, 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 standardisation, which simplifies manufacture and logistics, and specialisation, which may make the weapon significantly more effective. Small improvements in either logistics or effectiveness can translate into enormous operational advantages.

Some common torpedo diameters (using the most common designation, metric or inch, and listed in increasing order of size):
*12.75 inch (approximately 324 mm) is the most common size for light torpedoes.
*16 inch (406 mm) was the size of the earliest specialised Soviet ASW torpedoes. 16 inch torpedo tubes were fitted to Soviet Hotel, Echo and early Delta class submarines, often in addition to 21 inch tubes.
*17.7 inch (450 mm) was the standard size for light torpedoes of the Imperial Japanese Navy. This size is sometimes referred to as 18 inches.
*21 inch (533 mm) is the most common size for heavy torpedoes, including:
**Allied torpedoes of the Second World War.
**Some torpedoes of the Imperial Japanese Navy.
**Torpedoes of the Kriegsmarine
**NATO torpedoes.
**Some Soviet and Russian torpedoes, including the current ASW models.
*24 inch (610 mm) torpedoes were used by the Imperial Japanese Navy, most famously the deck launched Type 93 torpedo ('Long Lance'), also some Kaiten kamikaze torpedoes.
*650 mm (approximately 25.6 inches) is the largest torpedo diameter used by the Russian navy, see Type 65 torpedo. Adaptors are used to fire 533 mm (21 inch) munitions from 650 mm tubes.

Even larger sizes of torpedo tube, including 660 mm (26 inches), 30 inch (762 mm) and 36 inch (about 914 mm), have been installed on some nuclear submarines. These tubes are designed to be capable of firing large diameter munitions such as cruise missiles, as well as the standard 21 inch heavy torpedo. See torpedo tube.

Torpedoes used by various navies

A French Lynx helicopter carrying a mk46 torpedo

A Malafon torpedo-carrier missile, a weapon of the 1960s

German Navy

The torpedoes used by the Kriegsmarine included:
* G7a (T1)
* G7e (T2)
* T3
* T4 (Falke)
* G7es (Zaunkönig)
* T11

Russian Navy

Torpedoes used by the Russian Navy include:
* Type 53 torpedo
* Type 65 torpedo
* VA-111 Shkval torpedo

External links

* US Navy torpedo data cut and pasted from a Navy Fact File
* A slightly more recent writeup on the Mk-48 is available at a SSBN 624 web site by Clwyd
* Early History of the Torpedo Torpedo History
* US Naval Undersea Museum [https://www.keyportmuseum.cnrnw.navy.mil/torpedotech.htm Torpedo Display]
* US Naval Undersea Museum [https://www.keyportmuseum.cnrnw.navy.mil/torpedoes.htm Torpedo Collection]
*http://www.hansonclan.co.uk
*http://www.globalsecurity.org
*http://www.btinternet.com/~philipr/torps
*http://www.geocities.com/gwmccue
*http://www.geocities.com/Pentagon/1592/ustorp1
*http://navytorpedo.com
* Civil War Torpedoes
* http://naval.undersea.museum

Sources

*Blair, Clay. Silent Victory. Philadelphia: Lippincott, 1975.
*Milford, Frederick J. "U.S. Navy Torpedoes: Part One--Torpedoes through the Thirties". The Submarine Review, April 1996. {quarterly publication of the Naval Submarine League, P.O. Box 1146, Annandale, VA, 22003)
*_______. "U.S. Navy Torpedoes: Part Two--The Great Torpedo Scandal, 1941-43". The Submarine Review, October 1996.
*_______. "U.S. Navy Torpedoes: Part Three--WW II development of conventional torpedoes 1940-1946". The Submarine Review, January 1997.
*The Columbia Encyclopedia, Sixth Edition, online.
*Perry, Milton F. "Infernal Machines: The story of Confederate submarine and mine warfare." Louisiana State University Press, 1985.The
*Crowley, R.O. "Confederate Torpedo Service" in The Century / Volume 56, Issue 2, The Century Company, New York, June 1898.

Torpedo: Encyclopedia BETA

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