The torpedo, historically called a locomotive torpedo, is a self-propelled explosive projectile weapon, launched above or below the water surface, propelled underwater toward a target, and
designed to detonate on contact or in proximity to a target.
A Mark 32 Mod 15 Surface Vessel
Torpedo Tube (SVTT) fires a Mark 46 Mod 5 lightweight
torpedo.
Torpedoes may be launched from submarines, surface ships,
helicopters and fixed-wing aircraft, unmanned
naval mines and naval fortresses. They are also used
in conjunction with 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.
When the battleship had evolved primarily around battles between armoured ships with large guns, the torpedo allowed torpedo
boats, other lighter surface, subsurface ships and aircraft to destroy large ships without the bulk of large caliber guns, though
sometimes at the risk of being hit by longer-range shellfire. In the Battle off Samar,
destroyer mounted torpedos were the only weapons available to the US light task force capable of piercing Japanese cruisers and
battleships.
Etymology
The word torpedo comes from a 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 torpedo was
so named by Robert Fulton, who used it to refer to a towed gunpowder charge that was used
by his submarine Nautilus to
demonstrate that it could sink warships.
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.
Much like the invention of the helicopter, the earliest torpedoes are thought to have
existed as concepts many centuries before being developed as working devices. The earliest known description of what might be
called a torpedo is found in the work of Syrian engineer Hassan al-Rammah in 1275. His works show illustrations of a rocket-propelled device that appears to have been designed to move on the surface of water.[1]
Early naval "torpedoes"
Confederates laying torpedoes in Charleston Harbor
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".
Turtle dove under a British vessel and attach a bomb by means of an auger. The bomb was detonated by a timed fuse,
probably a type of clockwork mechanism. In its only recorded attack, Turtle failed to penetrate the hull of
HMS Eagle, which had been copper-plated to resist the action of shipworm.
The first usage of the term "torpedo" to refer to a naval explosive was by American inventor Robert Fulton. In 1800, Fulton
launched his submarine Nautilus, and demonstrated its method of attack
using a floating explosive charge Fulton called a "torpedo". The submarine would tow the torpedo, submerging beneath an enemy
vessel and dragging the torpedo into contact with it. Fulton successfully destroyed demonstration targets in both France and
Britain, but neither government was interested in purchasing the vessel and Fulton's experiments ceased in 1805.
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. (As self-propelled torpedoes were developed the tethered variety became
known as stationary torpedoes and later mines.) Several types of naval "torpedo" were developed and deployed, most
often by the Confederates, who faced a severe disadvantage in more traditional warfare methods.
Civil War "torpedoes" floated freely on the surface or were tethered to the bottom using a line and a weight holding the mine
just below the surface. They were detonated when struck by a ship, or after a set time, but were unreliable. 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 mined with Confederate torpedoes were often cleared
by Unionists placing captured Confederate soldiers with knowledge of the torpedoes' location in small boats ahead of the main
fleet.
"Torpedoes" (mines) could also be detonated electrically by an operator on shore, so 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. Electricity was a new technology, and the limitations of direct
current for effective distance was poorly understood, so failures were also possible because of the decrease in voltage
when the torpedoes were placed too far from the batteries. Former United States Navy
Commander Matthew Fontaine Maury, who served as a commander in the
Confederate Navy, did work on the development an underwater electrical mine.
David Farragut encountered tethered and floating contact mines in 1864 at the American
Civil War Battle of Mobile Bay. After his leading ironclad, USS Tecumseh, was sunk by a tethered
contact mine (torpedo), his vessels halted, afraid of hitting additional torpedoes. Inspiring his men to push forward, Farragut
famously yelled, "Damn the torpedoes, full speed ahead!"
The first torpedo designed to attack a specific target was the spar torpedo, an
explosive device mounted at the end of a spar up to 40 feet (12 m) long projecting forward underwater 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
David-class torpedo boats, among others. However these torpedoes would be able to cause
as much harm to their handlers as to their targets.
Bombs and booby traps
Illustration of naval torpedoes moored to the river bottom (the predecessors of modern naval mines)
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
fuses buried in the road by retreating Confederate forces to delay their pursuers.
These were the forerunners of modern land mines. Union generals publicly deplored this conduct.
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
Nordenfelt-class Ottoman
submarine
Abdülhamid (1886) was the first submarine in history to fire a torpedo while submerged. Two submarines of this class,
Abdülhamid (1886) and
Abdülmecid (1887) joined the
Ottoman fleet. They were
built in pieces by Des Vignes (Chertsey) and
Vickers (Sheffield) in
England, and assembled at the Taşkızak Naval Shipyard in
Istanbul,
Turkey.
Narrow miss by a German torpedo in World War I.
From World War I onwards, the word torpedo was used only for self-propelled projectiles that travelled under or on
water.
The first working prototype of the self-propelled torpedo we know today was created by a chance commission placed by
Giovanni Luppis, an Austrian naval
officer from Fiume (today Rijeka, Croatia), a port city of the Austrian Empire, on Robert Whitehead, an English engineer who was the manager of a
Fiume factory. In 1864, Luppis presented Whitehead with the plans of the salvacoste (coastsaver), a floating weapon,
driven by ropes from the land, and made a contract with him in order to perfect the invention.
Whitehead was unable to improve the machine substantially, since the clockwork motor, the attached ropes and the 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 (literally "mine ship"), the first real self-propelled torpedo,
officially presented to the Imperial Naval commission on December 21, 1866.
Maintaining proper depth was a major problem in the early days but Whitehead introduced his "secret" in 1868 which overcame
this. It was a mechanism consisting of a hydrostatic valve and pendulum which caused the
torpedo's hydroplanes to be adjusted so as to maintain a preset depth.
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 approximately 1000 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 (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).
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 18 inches (457 mm) in diameter and 19 feet (5.8 m) long, made of polished steel or
phosphor-bronze, with a 200 lb (90 kg) gun-cotton warhead. It was propelled by two propellers driven by a three-cylinder
Brotherhood engine, using compressed air of around 1300 lbf/in² (9 MPa). The torpedo was designed to self-regulate its course and
depth as far as possible.
Whitehead faced competition from the American Lieutenant Commander
John A. Howell, whose own design, driven by
flywheel, was simpler and cheaper. Whitehead purchased rights to the gyroscope in 1890 (ironically from Howell) to improve control of his designs, which came to be called the
"Devil's device".
On 16 January 1877, the Turkish steamer Intibah became the first vessel to be sunk by self-propelled 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, the first of which had been built at the shipyards of Sir
John Isaac Thornycroft in 1877, had gained recognition for its effectiveness and
the first torpedo boat destroyers (later simply destroyers) were built to
counter it. Torpedoes were also used to equip gunboats of around 1,000 tons displacement, thus
becoming torpedo gunboats.
Around 1897, Nikola Tesla patented a remote
controlled boat and later demonstrated the feasibility of radio-guided torpedoes to the
United States military, but they were not adopted until the 1960s.
Later, torpedoes were given (homing) guidance systems.
In the inter-war years tight budgets caused nearly all navies to skimp on testing their torpedoes. As a result, only the
Japanese had fully-tested torpedoes at the start of the Second World War. The lack of reliability caused major problems for the American submarine force in the
initial years of the American involvement in WW2, which primarily involved operations in the Pacific against Japanese shipping,
both civil and military.
All classes of ship, including submarines, and aircraft were armed with torpedoes.
Naval strategy at the time was to use torpedoes, launched from submarines or warships, to attack enemy warships in a fleet
action on the high seas. Targeting enemy merchant shipping was prohibited by rules of war.
There was concern torpedoes would be ineffective against warships' heavy armor; an answer to this was to detonate torpedoes
underneath a ship, breaking its back. This had been demonstrated by magnetic influence mines in
World War I: the shock wave of an explosion under a ship is well propagated by the water and
is very destructive. The torpedo is 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 the earth's magnetic field on ships and exploder mechanisms, which
resulted in premature detonation. The Kriegsmarine and the Royal Navy promptly identified and eliminated the problems. In the United States Navy there was an extended wrangle over the issue, exemplified in the three-fold
problems plaguing the Mark 14 torpedo. Cursory trials had allowed bad designs to enter
service. Both the Navy Bureau of Ordnance and the United States Congress were too busy protecting their own interests to correct the errors;
fully-functioning torpedoes only became available to the USN twenty-one months into the Pacific
War.[2]
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 m (200yd) at an average speed of 6.5
knots (12 km/h). 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 m (1100yd) at an average
speed of 35kt (64 km/h).
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. 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 was the use of water to cool the combustion chamber. This
not only solved heating problems so that more fuel could be burnt, 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.
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. The
Type 93 used pure oxygen instead of compressed air and had unmatched performance in World War II.
Steam
US WWII Torpedo belonging to PT-658 in Portland, OR
A derivative of the compressed-air torpedo was the steam torpedo. Developed by Vickers
Ltd, it mixed alcohol (first ethanol, later methanol) with compressed air in the combustion chamber,
producing "steam". This increased speed, but produced a visible wake.[3]
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 knots ( km/h) for over 2,400 m.
Flywheel
The Howell torpedo used by the US Navy in
the late 1800s featured a heavy flywheel which had to be spun up before launch. It was able to
travel about 400yd (365m) at 25 knots (46kph). The Howell torpedo 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.
Electric propulsion
Electric propulsion systems also avoided tell-tale bubbles. John Ericsson invented an
electrically propelled torpedo in 1873; it was powered via a cable from an external power source, as batteries of the time had insufficient capacity.
Germany introduced the first battery-powered torpedo shortly before World War II, the G7e. It was slower and had shorter range than the conventional G7a, but
was wakeless and much cheaper. Its lead-acid rechargeable battery was sensitive to shock, required frequent maintenance before use, and required
preheating for best performance. The experimental G7ep, an enhancement of the G7e, used primary
cells.
Modern electric torpedoes such as the Mark 24 Tigerfish or DM2 series commonly use
silver oxide batteries which need no maintenance, allowing torpedoes to be stored
for years without losing performance.
Modern propulsion systems
Modern torpedoes utilize a variety of drive mechanisms 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 or the German Barracuda, use supercavitation to
increase their speed to over 200 knots (370 km/h); compare the speed of the Mark 46
torpedo, which does not use supercavitation, of about 28 knots (32 mi/h, 52 km/h).
Torpedo classes and diameters
Torpedo tube aboard the French submarine
Argonaute
Torpedoes are launched several ways:
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.
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.
- 406 mm (16 inch) was the size of the earliest specialised Soviet ASW
torpedoes. inch ( mm) torpedo tubes were fitted to Soviet Hotel,
Echo and early Delta class
submarines, often in addition to 21 inch tubes.
- 450 mm (17.7 inch) was the standard size for light torpedoes of the Imperial
Japanese Navy. It was also widely used by Italian Navy (Regia Marina) during WWII; it was the common size of the torpedo
used by torpedo bomber. This size is sometimes referred to as 18 inches.
- 533 mm (21 inch) is the most common size for heavy torpedoes, including:
- 610 mm (24 inch) 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), 762 mm (30 inches) and 916 mm (about 36
inches), 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.
Guidance and tactics
WWI
Austrian battleship with torpedo nets.
The first guided torpedo was the Victorian era Brennan Torpedo which could be steered
onto its target by varying the relative speeds of its contra-rotating propellers. However the Brennan Torpedo required a
substantial infrastructure and was not suitable for ship-board use. Therefore for the first part of its history the torpedo was
guided only in the sense that its course could be regulated so as to maintain a fixed depth and, through gyroscopes, a straight
course. With such torpedoes the method of attack in small torpedo boats, Torpedo bombers and small submarines, was to set on a collision course abeam to the target and to release
the torpedo at the last minute, before peeling away; all the time running a gauntlet of defensive fire.
In larger ships and submarines fire control calculators gave a wider engagement envelope. Originally plotting tables with
specialised slide rules these could reconcile the speed, distance and course of a target with
the shooter's own speed and course, together with the performance of its torpedoes to give a firing solution. By the time of the
Second World War all sides had developed automatic calculators as exemplified by the US Torpedo Data Computer; although submarine commanders were still expected to be able to calculate a
firing solution by hand as a back up against mechanical failure.
Against high value targets and multiple targets individual submarines would launch a spread of torpedoes across the course of
the target or targets, 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 90 degrees to its original course and steam away from the torpedoes and the firer, allowing the
relatively short range torpedoes to use up their fuel. However an alternative was to "comb the tracks", turning 90 degrees
towards the torpedoes and the firing ship. The intention of such a tactic was still to minimise the size of target offered to the
torpedoes, but at the same time be able to aggressively engage the firer. This was the tactic Jellicoe's Battle of Jutland critics advocated, Jellicoe's caution at turning away from the torpedoes being seen
as the reason why the German fleet managed to escape.
The use of multiple torpedoes to engage single targets greatly reduces a submarines combat endurance and its ability to stay
on patrol.[4] This can be improved by insuring a target can
be effectively engaged by a single torpedo, this gave rise to the guided torpedo. Guided torpedoes can use passive and active
guidance or a mix of the two to give semi-active guidance. Passive acoustic torpedoes
home in on emissions from a target, usually noise. 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 in attack range.
Torpedoes can operate on a fire and forget principle or be controlled by its firing
vessel. During the Second World War the US experimented with frequency
hopping radio controlled torpedoes using matching pairs of punched card rolls based on those of player pianos. Modern torpedoes
use an umbilical wire; the advantage of the umbilical being the processing power that can be fitted into the hull of a submarine
or ship is vastly greater than that which can be fitted into even the largest torpedo. Torpedoes such as the Mark 48 torpedo can operate in a variety of modes increasing tactical flexibilty.
A ship's acoustic signature is not the only emission that a torpedo can home in
on. To engage the US super carriers the Soviet Union developed the 53-65 wake homing torpedoes.
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
Modern German Navy:
The torpedoes used by the WWII Kriegsmarine included:
Imperial Japanese Navy
The torpedoes used by the Imperial Japanese Navy (WWII) included:
Indian Navy
- Advanced Experimental Torpedo (Light weight torpedo)
- Varunastra (Heavy weight torpedo)
- Takshak (Thermal torpedo) [5]
Royal Navy
The torpedoes used by the Royal Navy include:
Russian Navy
Torpedoes used by the Russian Navy include:
U.S. Navy
The four major torpedoes in the United States Navy inventory are:
See also
References
- ^ Prof. Dr. Mohamed Mansour (2002-03-22). Muslim Rocket Technology.
MuslimHeritage.com. Retrieved on 2007-07-18.
- ^ Blair, p.20
- ^ Blair, p.30-1.
- ^ The Attack Submarine suggests shorter patrols actually
improve effectiveness.
- ^ NSTL achievements
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.
- O'Kane, Richard H. (1987). "Seventh Patrol", Wahoo: The Patrols of America's Most Famous World War II Submarine.
Novato, California: Presidio Press.
- Perry, Milton F. "Infernal Machines: The story of Confederate submarine and mine warfare." Louisiana State University Press,
1985.
- Crowley, R.O. "Confederate Torpedo Service" in The Century / Volume 56, Issue
2, The Century Company, New York, June 1898.
External links
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