English
Verb
torpedoed
- past of torpedo
The modern torpedo (historically called an
automotive, automobile, locomotive, or fish 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. The original use of "torpedo" was for a variety of devices
that would today be mostly called a "
mine".
However, from the First World War onwards "torpedo" was only used
for an underwater self-propelled missile, often called colloquially
a "fish".
Today's torpedoes can be divided into lightweight
and heavyweight classes, and into straight running, autonomous
homers and wire-guided ones. They can be launched from a variety of
platforms. Originally, the torpedo was primarily used in an
anti-shipping role. This has been largely superseded by the
missile, so the torpedo's main contemporary use is against
submarines.
Launch platforms
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; for example the
Mark 46 torpedo
used by the
United
States becomes the warhead section of the
ASROC (Anti-Submarine
ROCket) and the
CAPTOR mine
(CAPsulated TORpedo) is a submerged sensor platform which releases
a torpedo when a hostile contact is detected.
While the battleship had evolved primarily around
engagements between armoured ships with large guns, the torpedo
allowed
torpedo
boats, other lighter surface ships, submersibles, and aircraft
to destroy large ships without large-caliber guns, though sometimes
at the risk of being hit by longer-range shellfire. In the
Battle of
Samar, destroyer-mounted torpedoes were the only weapons
available to the U.S. task force capable of damaging opposing
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). In naval usage, the torpedo was so named by
Robert
Fulton, who used it to refer to a towed gunpowder charge used
by his
submarine
Nautilus
to demonstrate it could sink warships.
History
Prior to the invention of the self-propelled
torpedo, the term was applied to any number of different types of
explosive devices, generally having the property of being secret or
hidden, including devices which today would include
booby traps,
land
mines,
naval mines,
and others.
Much like the invention of the helicopter, the
earliest torpedo concepts existed many centuries before being
developed as working devices. The earliest known description 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.
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 function.
Turtle dived under a British vessel to attach a bomb by means of an
auger. The bomb was to be 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
shipworms.
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.
In this period, "torpedoes" floated freely on the
surface or were bottom-moored 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 (as demonstrated also by
Fulton), 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
Maury, who served as a commander in the
Confederate
Navy, worked on the development of 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 ordered, "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, as well as by
David-class
torpedo boats, among others. However, these torpedoes were liable
to cause as much harm to their users as to their targets.
Bombs and booby traps
During the US Civil War, the term "torpedo" was
also used to refer to various types of bombs and
boobytraps. 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
small arms
rounds) moored at
City
Point, Virginia, on the
James
River. The explosion caused more than
US$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
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 modern
self-propelled torpedo was created by a commission placed by
Giovanni
Luppis (Ivan Lupis), 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 (mine ship), the first real self-propelled torpedo,
officially presented to the Austrian 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 Austrian 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).
Royal Navy
representatives visited Fiume to see a demonstration in late 1869
and in 1870 a batch of torpedoes was ordered. In 1871, the British
Admiralty
paid him
£15,000
for certain of his developments and production started at the Royal
Laboratories in Woolwich the following year. In 1893, RN torpedo
production was transferred to the Royal Gun Factory. The British
later established a Torpedo Experimental Establishment at
HMS Vernon and
a production facility at the Royal Naval Torpedo Factory, Greenock
in 1910. These are now closed.
Whitehead opened a new factory near
Portland
harbour,
England in 1890,
which continued making torpedoes until the end of the Second World
War. Because orders from the RN were not as large as expected,
torpedoes were mostly exported. A series of devices was produced at
Fiume, from 14" upward. 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 at around 1300 lbf/in² (9
MPa). The torpedo was designed to self-regulate its course and
depth as far as possible. By 1881, nearly 1500 torpedoes had been
produced. Whitehead also opened a factory at St Tropez in 1890
which exported torpedoes to Brazil, Holland, Turkey and Greece.
Whitehead faced competition from the American
Lieutenant
Commander John A.
Howell, whose
own
design, driven by
flywheel, was simpler and
cheaper. It was produced from 1885 to 1895, and left no wake and
ran straight. A Torpedo Test Station had been set up on Rhode
Island in 1870, and an automobile torpedo produced in 1871 but this
was unsuccessful. The Lay torpedoes were also largely unsuccessful
as were various privately invented ones. The Howell torpedo was the
only USN one until Whitehead torpedoes produced by Bliss and
Williams (later E W Bliss and Co) came into service in 1894. Five
varieties were produced, all 45 cm diameter. An improved version,
the
Bliss-Leavitt,with
a turbine engine was later produced, some with a larger diameter.
Various versions were used in both World War I and World War
II.
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 (ironically from Howell) to improve control of his
designs, which came to be called the "Devil's Device". The firm of
L.
Schwartzkopf 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 at Fiume could not meet
demand.
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
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 on
April 23
1891 by a
torpedo from the gunboat
Almirante
Lynch, during the
Chilean
Civil War.
By this time the
torpedo
boat, the first of which had been built at the shipyards of Sir
John
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, thus becoming
torpedo
gunboats.
Originally, torpedoes were designed to be
straight running, though this was not always the case in practice.
Around 1897,
Nikola Tesla
patented a
remote
controlled boat and later demonstrated the feasibility of
radio-guided torpedoes to the
United
States military.
Torpedoes were widely used in the First World
War, both against shipping and against submarines. Germany and its
allies 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.
Originally the Japanese Navy purchased Whitehead
or Schwartzkopf torpedoes but by 1917 they were conducting
experiments with oxygen as a fuel. 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
torpedoes.
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 (in particular the
Type
93) at the start of
World War
II. The lack of reliability caused major problems for the
American Submarine Force in the initial years of the American
involvement in
World War
II, primarily in the
Pacific
War.
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, against
enemy warships in a fleet action on the high seas. Targeting
unarmed enemy merchant shipping was prohibited by
rules of
war. (In the event, merchantmen were armed and acted as de
facto naval auxiliaries, rendering the distinction moot.) 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 was demonstrated by
magnetic
influence mines in
World War
I. 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. 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
Royal
Navy promptly identified and eliminated the problems. In the
United
States Navy, 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. 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.
British submarines used torpedoes to interdict
the Axis supply shipping to North Africa and the
Fleet Air
Arm Swordfish
sank three Italian battleships at Taranto by torpedo. Torpedoes
were used by British surface vessels to help finish off the German
battleship
Bismarck.
Large tonnages of merchant shipping were sunk by U-boats with
torpedoes; as in World War One, the Germans also made extensive use
of deck guns.
Later in the Second World War, torpedoes were
given acoustic (homing)
guidance
systems, originally by the Germans in the
G7es
torpedo, and they were a significant factor in the Allied
victory in the
Battle
of the Atlantic. Pattern-following and wake homing torpedoes
were also developed. Acoustic homing formed the basis for torpedo
guidance after the Second World War. Though Lupis' original design
had been rope guided, torpedoes were not wireguided until the
1960s. 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 submarines, which did not have to surface often,
particularly those carrying strategic nuclear missiles.
Energy sources
Compressed air
This first successful self-propelled
Whitehead 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, which increased engine
performance further, because the air expanded even more after
heating. This was the principle used by the Brotherhood
engine.
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 by Whitehead's company.
Wet-heater
A further enhancement was the use of water to
cool the
combustion
chamber. This not only solved heating problems so 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. A simpler system was
introduced by the British Royal Gun factory in 1908. 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
(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. During the war, Germany experimented with hydrogen
peroxide for the same purpose.
Steam
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.
Wire driven
The
Brennan
torpedo had two wires wound around drums inside the torpedo. A
shore based steam
winch
pulled the wires, which spun the drums and drove the propeller.
Such systems were used for
coastal
defence of the British homeland and colonies from 1887 to 1903.
Speed was about 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 (365 m) at 25
knots (46 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 the very early Whitehead
models.
Electric batteries
Electric propulsion systems also avoided
tell-tale bubbles.
John
Ericsson invented an electrically propelled torpedo in 1873; it
was powered by a cable from an external power source, as
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 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.
Rockets
A number of experimental rocket propelled torpedoes
were tried soon after Whitehead's invention. They were not
successful. However rocket propulsion has again recently been used
in Russian and German torpedoes (see below).
Modern drive systems
Modern torpedoes utilize a variety of
drive mechanisms, including gas turbines (the British
Spearfish),
monopropellants,
and
sulphur
hexafluoride gas sprayed over a block of solid
lithium. Some torpedoes, such as
the Russian
VA-111
Shkval, the Iranian
Hoot or
the proposed German Unterwasserlaufkörper / Barracuda , use
supercavitation
to increase their speed to over 200 knots (370 km/h); compare the
speed of the
Mark 48
torpedo, which does not use supercavitation, of about 55 knots
(63 mi/h, 101 km/h).
Propulsion
The first of Whitehead's torpedoes had a single
propeller and so needed a large vane to stop it turning in a
circle. Not long afterwards the idea of contra-rotating propellers
was introduced (at Woolwich), so not requiring the vane. The three
bladed propellor came in 1893 and the four bladed one in 1897. To
minimise noise, today's torpedoes often use pump jets.
Guidance and tactics
The first guided torpedo was the Victorian era
Brennan, which could be steered onto its target by varying the
relative speeds of its contra-rotating propellers. However the
Brennan 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 its course could be
regulated so as to achieve an intended impact depth (due to the
sine wave running path of the Whitehead, 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
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 (in large ships), combined with specialised
slide rules
(known in U.S. service as the "banjo" and "Is/Was"), 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. Submarine commanders were still expected to be
able to calculate a firing solution by hand as a back up against
mechanical failure, and because many submarines existing 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 math (which was simple
trigonometry) without recourse to paper calculations, from
extensive training.
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 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. An
alternative was to "comb the tracks", turning 90 degrees towards
the torpedoes. 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
advocated by critics of Jellicoe's actions at
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 greatly reduces a submarine's combat endurance and its
ability to stay on patrol. This can be improved by ensuring a
target can be effectively engaged by a single torpedo, which gave
rise to the guided torpedo. Guided torpedoes can use passive or
active guidance, or a mix of the two. Passive
acoustic
torpedoes 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 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 U.S. 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 is the vastly greater computer processing power of
the submarine or ship can be used. Torpedoes such as the U.S.
Mark 48
can operate in a variety of modes increasing tactical
flexibility.
Homing
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. supercarriers, the Soviet Union developed the
53-65
wake-homing torpedo.
Warhead/fuzing
The
warhead is generally some form
of
aluminised
explosive, because the sustained explosive pulse produced by the
powdered aluminium is particularly destructive against underwater
targets.
Torpex was popular
until the 1950s, but has been superseded by
PBX
compositions.
Nuclear
warheads for torpedoes have also been developed e.g. the
Mark 45
torpedo. In lightweight antisubmarine torpedoes designed to
penetrate submarine hulls, a
shaped
charge can be used.
Detonation may
be triggered by direct contact with the target, or by a proximity
fuze incorporating sonar
and/or magnetic sensors.
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 out-manoeuvre a target. Good
hydrodynamics are needed for it to attain high speed efficiently
and also to give long range since the torpedo has limited stored
energy.
Torpedo classes and diameters
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, 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. torpedo tubes were fitted to Soviet Hotel,
Echo
and early Delta
class submarines, often in addition to 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 World War II; it was the common size of the torpedo
used by torpedo bomber. This size is sometimes referred to as .
- 483 mm (19 inch) was the size for the first U.S. homing
torpedo, the Mark
24, also known as Fido.
- 533 mm (21 inch) is the most common size for heavy torpedoes,
including:
- 610 mm (24 inch) torpedoes, most famously the Type 93 ('Long
Lance'), were used by Imperial Japanese Navy destroyers and
cruisers, and as the basis for some Kaiten.
- 650 mm (approximately 25.6 inches) is the largest torpedo
diameter used by the Russian navy, such as the Type
65. Adaptors are used to fire 533 mm (21 inch) models 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 in heavy torpedo.
Torpedoes used by various navies
German Navy
Modern
German
Navy:
The torpedoes used by the World War II
Kriegsmarine
included:
Imperial Japanese Navy
The torpedoes used by the
Imperial
Japanese Navy (World War II) included:
Indian Navy
- Advanced Experimental Torpedo (lightweight torpedo)
- Varunastra (heavyweight torpedo)
- Takshak (heavy weight torpedo)
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:
Launchers
Ship
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 which dropped the torpedo
into the sea. Royal Navy
Coastal
Motor Boats of WW1 used a rear-facing trough and a
cordite ram to push the
torpedoes into the water tail-first.
Developed in the run up to Second World War,
multiple-tube mounts (up to quintuple in some ships) for 21" to 24"
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), making them true turrets
and increasing the broadside without adding tubes and
top hamper (as
the quadruple and quintuple mounts did). Considering their
Type
93s possible war winners, IJN equipped their cruisers with
torpedoes. The Germans also equipped their capital ships with
torpedoes.
Smaller vessels such as PT boats would carry
their torpedoes in fixed deck mounted tubes using compressed air.
These were either aligned to fire forward or at an angle to the
centerline.
Late in the war lightweight mounts for 12.75"
homing torpedoes were developed for anti-submarine use consisting
of triple launch tubes used on the decks of ships. These were the
Mark 32 launcher in the USA and part of STWS (Shipborne Torpedo
Weapon System) in the UK. Later a below-decks launcher has been
used by the RN. This basic launch system continues to be used to
this day with improved torpedoes and fire control systems.
Submarines
Submarine launched weapons now use compressed
air, or the torpedoes swim out, or are pushed out by hydraulic ram.
Both bow and stern tubes were fitted. However now only the former
are used. The first French and Russian submarines carried their
torpedoes externally in
Drzewiecki
drop
collars. These were cheaper than launch tubes but
unreliable.
Late in World War Two, the U.S. adopted a 16"
(40cm) homing torpedo for use against escorts.
Air launch
Torpedoes may be carried by fixed-wing aircraft,
helicopters or missile. They are launched from the first two at
prescribed speeds and altitudes, dropped from bomb-bays or
underwing
hardpoints.
Torpedo handling equipment
Although lightweight torpedoes
are fairly easily handled, the transport and handling of
heavyweight ones is difficult, especially in the small space of 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.
References
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.