Sting Ray torpedo
Encyclopedia
The Sting Ray torpedo is a current British
acoustic homing
light-weight torpedo
(LWT) manufactured by GEC-Marconi, who were later bought out by BAE Systems
. It entered service in 1983.
with a British-built torpedo to replace the imported Mk 44
and Mk 46
US weapons. In the 1950s the Royal Navy
was equipped with British designed and built Mk 30 air-dropped torpedoes. These were passive homing weapons which relied on detecting the noise from submarine targets. However, as submarine noise levels reduced, these weapons became ineffective. Nuclear submarines could easily out-run and out-dive the Mk 30.
A design for a British Mk 31 torpedo, which would have used active echo-location
sonar
, failed to receive Government approval for production and US Mk 44 torpedoes were purchased for the Royal Navy in the 1960s. These were later replaced by US Mk 46 torpedoes.
Design studies in the mid-1960s proposed that a tank of polyethylene oxide
be carried behind the warhead. This polymer would be exuded at the nose to reduce the drag coefficient
. Experiments using buoyancy-propelled torpedoes in 1969 had shown reductions in the drag coefficient up to 25%. However, by 1969 this scheme had been rejected in favour of carrying a larger battery.
The homing system developed in the mid-1960s incorporated a spinning magnetic disc onto which the acoustic correlation algorithms were etched but this was replaced by integrated circuit
technology when the disc sometimes failed to survive the impact of the weapon with the sea from high altitude launches.
The original warhead
concept was for a simple omnidirectional blast charge. However, studies in the 1970s showed that this would be inadequate against the large double-hulled submarines then entering service. A directed energy (shaped charge
) warhead was used in the production weapon.
In 1976 the designs had to be completely revised. Swapping the project for buying a ready-made US torpedo was not considered because the torpedo was expected to be better, and was all-British. The project manager was Eric Risness CBE.
). Guidance systems were made by Sperry Gyroscope Company.
/silver-chloride sea water battery
. The propulsion method combines high speed, deep diving, agility and low noise levels. The weapon is provided with target and environmental information by the launching platform. Once launched it operates autonomously, with tactical software searching for the target using active sonar and then homing in without any further assistance. The software is designed to deal with the employment of countermeasures by the target. The weapon is designed to be launched from fixed wing or rotary winged aircraft and surface ships against submarine targets.
The development of the torpedo cost £920 million. The Mark 24 Tigerfish
submarine-launched torpedo had also overshot its initial budget.
warhead. It has a speed of 83 km/h (45 knots) over a range of 8,000 metres (4.3 nautical mile
s).
Sting Ray Mod 1 is intended to used against the same targets as Sting Ray Mod 0 but with an enhanced capability against small clad conventional submarines via a shaped-charge warhead, and an improved shallow-water performance. It shares many hull components with the original weapon.
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
acoustic homing
Acoustic homing
Acoustic homing is a system which uses sound to guide a moving object, such as a torpedo. Acoustic homing can be either Passive or Active in nature....
light-weight torpedo
Torpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...
(LWT) manufactured by GEC-Marconi, who were later bought out by BAE Systems
BAE Systems
BAE Systems plc is a British multinational defence, security and aerospace company headquartered in London, United Kingdom, that has global interests, particularly in North America through its subsidiary BAE Systems Inc. BAE is among the world's largest military contractors; in 2009 it was the...
. It entered service in 1983.
Design and development
The early 1960s concept was to provide the Royal NavyRoyal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
with a British-built torpedo to replace the imported Mk 44
Mark 44 torpedo
The Mark 44 torpedo is an obsolete air-launched and ship-launched lightweight torpedo manufactured in the U.S., and under licence in Canada, France, Italy, Japan and the United Kingdom with 10,500 being produced for U.S. service. It was superseded by the Mark 46 torpedo...
and Mk 46
Mark 46 torpedo
Designed to attack high-performance submarines, the Mark 46 torpedo is the backbone of the U.S. Navy's lightweight ASW torpedo inventory, and is the current NATO standard. These aerial torpedoes, such as the Mark 46 Mod 5, are expected to remain in service until the year 2015...
US weapons. In the 1950s the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
was equipped with British designed and built Mk 30 air-dropped torpedoes. These were passive homing weapons which relied on detecting the noise from submarine targets. However, as submarine noise levels reduced, these weapons became ineffective. Nuclear submarines could easily out-run and out-dive the Mk 30.
A design for a British Mk 31 torpedo, which would have used active echo-location
Acoustic location
Acoustic location is the science of using sound to determine the distance and direction of something. Location can be done actively or passively, and can take place in gases , liquids , and in solids .* Active acoustic location involves the creation of sound in order to produce an echo, which is...
sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
, failed to receive Government approval for production and US Mk 44 torpedoes were purchased for the Royal Navy in the 1960s. These were later replaced by US Mk 46 torpedoes.
Design
A desire not to be dependent on US torpedo purchases led to a research programme starting in 1964 to develop a British torpedo. Initially designated Naval and Air Staff Requirement (NASR) 7511, it was subsequently designated the Sting Ray torpedo.Design studies in the mid-1960s proposed that a tank of polyethylene oxide
Polyethylene glycol
Polyethylene glycol is a polyether compound with many applications from industrial manufacturing to medicine. It has also been known as polyethylene oxide or polyoxyethylene , depending on its molecular weight, and under the tradename Carbowax.-Available forms:PEG, PEO, or POE refers to an...
be carried behind the warhead. This polymer would be exuded at the nose to reduce the drag coefficient
Drag coefficient
In fluid dynamics, the drag coefficient is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment such as air or water. It is used in the drag equation, where a lower drag coefficient indicates the object will have less aerodynamic or...
. Experiments using buoyancy-propelled torpedoes in 1969 had shown reductions in the drag coefficient up to 25%. However, by 1969 this scheme had been rejected in favour of carrying a larger battery.
The homing system developed in the mid-1960s incorporated a spinning magnetic disc onto which the acoustic correlation algorithms were etched but this was replaced by integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
technology when the disc sometimes failed to survive the impact of the weapon with the sea from high altitude launches.
The original warhead
Warhead
The term warhead refers to the explosive material and detonator that is delivered by a missile, rocket, or torpedo.- Etymology :During the early development of naval torpedoes, they could be equipped with an inert payload that was intended for use during training, test firing and exercises. This...
concept was for a simple omnidirectional blast charge. However, studies in the 1970s showed that this would be inadequate against the large double-hulled submarines then entering service. A directed energy (shaped charge
Shaped charge
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...
) warhead was used in the production weapon.
In 1976 the designs had to be completely revised. Swapping the project for buying a ready-made US torpedo was not considered because the torpedo was expected to be better, and was all-British. The project manager was Eric Risness CBE.
Manufacture
The torpedo was built at the MSDS plants at Neston (in CheshireCheshire
Cheshire is a ceremonial county in North West England. Cheshire's county town is the city of Chester, although its largest town is Warrington. Other major towns include Widnes, Congleton, Crewe, Ellesmere Port, Runcorn, Macclesfield, Winsford, Northwich, and Wilmslow...
). Guidance systems were made by Sperry Gyroscope Company.
Deployment
The original in-service version (Sting Ray Mod 0) entered service in 1983. It is propelled by a pump jet driven by an electric motor. Power is supplied by a magnesiumMagnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
/silver-chloride sea water battery
Flow battery
A flow battery is a form of rechargeable battery in which electrolyte containing one or more dissolved electroactive species flows through an electrochemical cell that converts chemical energy directly to electricity...
. The propulsion method combines high speed, deep diving, agility and low noise levels. The weapon is provided with target and environmental information by the launching platform. Once launched it operates autonomously, with tactical software searching for the target using active sonar and then homing in without any further assistance. The software is designed to deal with the employment of countermeasures by the target. The weapon is designed to be launched from fixed wing or rotary winged aircraft and surface ships against submarine targets.
The development of the torpedo cost £920 million. The Mark 24 Tigerfish
Mark 24 Tigerfish
The Mk 24 Tigerfish torpedo was a heavyweight acoustic homing torpedo used by the Royal Navy for several years. The early Mod0 and Mod1 variants were unreliable and unsuccessful, and were issued to the RN even though they failed Fleet Weapon Acceptance...
submarine-launched torpedo had also overshot its initial budget.
Dimensions
Sting Ray has a diameter of 324 mm (12¾ inches) and a length of around 2.6 metres (8.5 feet). It has a launch weight of 267 kg (589 lb), and carries a 45 kg (99 lb) TorpexTorpex
Torpex is a secondary explosive 50% more powerful than TNT by mass. Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for Torpedo Explosive', having been originally developed for use in torpedoes...
warhead. It has a speed of 83 km/h (45 knots) over a range of 8,000 metres (4.3 nautical mile
Nautical mile
The nautical mile is a unit of length that is about one minute of arc of latitude along any meridian, but is approximately one minute of arc of longitude only at the equator...
s).
Sting Ray Mod 1 is intended to used against the same targets as Sting Ray Mod 0 but with an enhanced capability against small clad conventional submarines via a shaped-charge warhead, and an improved shallow-water performance. It shares many hull components with the original weapon.
Specifications
- Length : 2.6 m
- Diameter : 324 mm
- Weight : 267 kg
- Warhead : 45 kg of HEExplosive materialAn explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...
in a shaped charge - Speed : 45 knots
- Range : 8–11 km
- Depth : 800 m
- Propulsion : Magnesium/silver chlorideSilver chlorideSilver chloride is a chemical compound with the chemical formula AgCl. This white crystalline solid is well known for its low solubility in water . Upon illumination or heating, silver chloride converts to silver , which is signalled by greyish or purplish coloration to some samples...
seawater battery (Pump-jetPump-jetA pump-jet, hydrojet, or water jet, is a marine system that creates a jet of water for propulsion. The mechanical arrangement may be a ducted propeller with nozzle, or a centrifugal pump and nozzle...
) - Guidance : Active/Passive sonarSonarSonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
