Spearfish torpedo

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TypeHeavyweight torpedo
Place of originUnited Kingdom
Service history
In service1992–present
Used byRoyal Navy
Production history
ManufacturerBAE Systems Underwater Systems
Mass1,850 kg (4,080 lb)
Length7 m (23 ft)
Diameter533 mm (21 in)

Maximum firing range54 km (29 nmi)[1][dead link]
WarheadAluminised PBX explosive
Warhead weight300 kg (660 lb)
Proximity or contact detonation

EngineSundstrand gas-turbine with pump-jet
PropellantHAP / Otto fuel II[1]
Maximum speed 70-mile-per-hour (113 km/h)
Wire-guided with autonomous active terminal homing sonar

The Spearfish torpedo (formally Naval Staff Target 7525) is the heavy torpedo used by the submarines of the Royal Navy. It can be guided by wire or by autonomous active or passive sonar, and provides both anti-submarine warfare (ASW) and anti-surface ship warfare (ASuW) capability.

It replaced the unreliable Tigerfish torpedo, which was withdrawn in 2004; the significantly higher 70 miles per hour (110 km/h) speed of the Spearfish,[2] for which development started in the 1970s, before the breakup of the Soviet Union, was intended to catch high-speed, deep-diving Soviet threats such as the Alfa-class submarine.


The torpedo is driven by a pump-jet coupled to a Hamilton Sundstrand 21TP04 gas turbine engine 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.[3]

A microprocessor 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 fuze (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.[4] This can be seen in SINKEX video footage.[5]


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.


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.


The production contract for the Spearfish Torpedo was placed with GEC-Marconi Underwater Systems Ltd (now BAE Systems) in 1983, following a development programme lasting several years.


Spearfish entered full production in 1988, with deliveries completed in 2003; the number ordered has not been revealed. Spearfish torpedoes are stored and serviced at Beith Ordnance Storage facility in North Ayrshire.


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.[6][7]

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,[8] a change to the fuel system to improve safety, full digitisation of the weapon and a new fibre optic guidance link to improve performance.[9] The upgraded torpedoes will enter service between 2020 and 2024.[10]

See also


  1. 1.0 1.1 "Spearfish advanced heavyweight torpedo" (PDF). BAE Systems. December 2011.
  2. Tovey, Alan (16 December 2014). "Already faster than a cheetah, the Navy's two-tonne Spearfish torpedoes are getting an upgrade". The Telegraph.
  3. Bellerby, John M.; Christopher S. Blackman (2004). "The Interaction between Otto Fuel II and Aqueous Hydroxylammonium Perchlorate (HAP), Part I: Initial Observations and Time-to-Event Measurements". Propellants, Explosives, Pyrotechnics. 29 (5): 262–266. doi:10.1002/prep.200400055. Retrieved 22 July 2013.
  4. Branfill-Cook, Roger (2014). Torpedo: The Complete History of the World's Most Revolutionary Naval Weapon. Seaforth Publishing. p. 157. ISBN 978-1848322158.
  5. "HMAS Waller fires MK 48 Mod 7 (CBASS) torpedo". RIMPAC 08 Footage. Retrieved 22 July 2013.
  6. "Spearfish heavyweight torpedo". Products. BAE Systems. Retrieved 5 June 2015.
  7. "Britain's 2009-2019 Torpedo Support Contract". Defense Industry Daily. 10 August 2009.
  8. Richard Scott (15 December 2014). "UK contracts Spearfish torpedo upgrade". IHS Jane's Defence Weekly.
  9. "£270 million Royal Navy torpedo upgrade sustains hundreds of UK jobs". Ministry of Defence. 15 December 2014. Retrieved 15 December 2014.
  10. Chuter, Andrew (16 December 2014). "Royal Navy Subs To Get Upgraded Spearfish Torpedo". Defense News.

External links