The Spearfish torpedo (formally Naval Staff Target 7525) is the heavy

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, ...

used by the

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

s of the

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against Fr ...

. It can be guided by

wire Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm A wire is a flexible strand of metal. Wire is co ...

or by autonomous active or passive sonar, and provides both

anti-submarine warfare Anti-submarine warfare (ASW, or in older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are typ ...

(ASW) and

anti-surface warfare Anti-surface warfare (ASuW or ASUW) is the branch of naval warfare concerned with the suppression of surface combatants. More generally, it is any weapons, sensors, or operations intended to attack or limit the effectiveness of an adversary's ...

(ASuW) capability. Spearfish development began in the 1970s, with production starting in 1988, and deployment in 1992. By 2004, the new weapon had completely replaced the older

Tigerfish Tigerfish can refer to fish from various families, and derives from official and colloquial associations of these with the tiger (''Panthera tigris''). However, the primary species designated by the name "tigerfish" are African and belong to the ...

torpedo. It is one of the most advanced torpedoes in the world.

Design

The torpedo is driven by a

pump-jet A pump-jet, hydrojet, or water jet is a marine system that produces a jet of water for propulsion. The mechanical arrangement may be a ducted propeller ( axial-flow pump), a centrifugal pump, or a mixed flow pump which is a combination of bot ...

coupled to a

Hamilton Sundstrand Hamilton Sundstrand was an American globally active corporation that manufactured and supported aerospace and industrial products for worldwide markets. A subsidiary of United Technologies Corporation, it was headquartered in Windsor Locks, Con ...

21TP04

gas turbine engine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the direct ...

using Otto fuel II and hydroxyl ammonium perchlorate as oxidiser. The addition of an oxidiser improves the specific energy of the fuel by reducing the fuel-richness of the Otto fuel. The Spearfish, which are capable of travelling at , were designed to catch high-speed, deep-diving

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

threats such as the . A

microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circ ...

enables the torpedo to make autonomous tactical decisions during the attack. It has a powerful blast warhead, triggered by either contact detonation (against a submarine hull) or an acoustic

proximity fuse A proximity fuze (or fuse) is a fuze that detonates an explosive device automatically when the distance to the target becomes smaller than a predetermined value. Proximity fuzes are designed for targets such as planes, missiles, ships at sea, an ...

(for under-keel detonation against ships). A standoff detonation under the keel enhances blast effects against surface ships through the amplification of stress resulting from the interaction of the explosion's products and the flexible structure of the ship.

Guidance

In a typical engagement, Spearfish will run out wire-guided to the general vicinity of the target and then conduct a covert passive search. The high-capacity guide wire system, specifically designed to match the Spearfish's manoeuvre and speed envelope, provides two-way data exchange between the torpedo and launch submarine, maximising the submarine's organic sensor and combat control capabilities. Once at close range the Spearfish uses active sonar to classify and home in on its target. High-power transmissions and sophisticated signal processing enable Spearfish to accurately discriminate targets from background noise and ensure high resistance to acoustic countermeasures and/or evasive manoeuvres. Should Spearfish fail to hit the target on its first attack, it automatically selects an appropriate re-attack mode until it successfully concludes the engagement.

Testing

Tactical software has been extensively refined through real-time, hardware in the loop simulations and demonstrated in more than 500 in-water trials and exercise firings.

Production

The production contract for the Spearfish Torpedo was placed with GEC-Marconi Underwater Systems Ltd (now

BAE Systems BAE Systems plc (BAE) is a British multinational arms, security, and aerospace company based in London, England. It is the largest defence contractor in Europe, and ranked the seventh-largest in the world based on applicable 2021 revenue ...

) in 1983, following a development programme lasting several years. Spearfish entered full production in 1988.

Deployment

The first Spearfish were deployed in 1992, with deliveries completed in 2003; the number ordered has not been revealed. Spearfish torpedoes are stored and serviced at

Beith Beith is a small town in the Garnock Valley, North Ayrshire, Scotland approximately south-west of Glasgow. The town is situated on the crest of a hill and was known originally as the "''Hill o' Beith''" (hill of the birches) after its ''Court ...

Ordnance Storage facility in

North Ayrshire North Ayrshire ( gd, Siorrachd Àir a Tuath, ) is one of 32 council areas in Scotland. The council area borders Inverclyde to the north, Renfrewshire and East Renfrewshire to the northeast, and East Ayrshire and South Ayrshire to the east a ...

Upgrade

In 2009, an upgrade programme began, leading to further sophisticated advances in Spearfish's homing, warheads, tactical and fuelling systems, as well as an upgraded guidance link. This will last until 2019. On 15 December 2014, the Ministry of Defence awarded BAE Systems a £270 million contract to upgrade the Spearfish torpedo. The upgrade includes a new insensitive-munition warhead from

TDW TDW (Gesellschaft für verteidigungstechnische Wirksysteme mbH) is the European leader in the development and manufacture of warheads for guided weapons. The company was founded in 1994 and has 130 employees based in Schrobenhausen, Germany. T ...

, a change to the fuel system to improve safety, full digitisation of the weapon and a new fibre optic guidance link to improve performance. The upgraded 'MOD 1' torpedoes will enter service between 2020 and 2024. In February 2021 test fired 3 upgraded 'MOD 1' specification Spearfish torpedoes as part of their final testing before entry into service with the Royal Navy.

References

External links

Spearfish Torpedo
{{Royal Navy torpedoes Cold War weapons of the United Kingdom Torpedoes of the United Kingdom Naval weapons of the United Kingdom BAE Systems weapons systems General Electric Company Weapons and ammunition introduced in 1992