Already one of the finest heavyweight torpedoes in the world, the programme to further enhance the accuracy and lethality of Spearfish is now complete. After extensive development and trials, the weapon has now been declared operational by the RN.
The Spearfish upgrade project began in 2010 to ensure the primary conventional weapon of the submarine fleet remains at the cutting edge. Given the current paucity of anti-ship weaponry in the surface fleet, the performance of this heavyweight torpedo is especially critical. For the Mod-1 update, virtually every aspect of the weapon has been improved, including the homing system and a new high bandwidth fibre optic data link. Spearfish can be wire-guided by commands sent down the data link from the submarine’s combat system. The command wire, which can run out to at least 30km, allows the targets to be changed, depth and range restrictions set, and countermeasures ignored. The submarine’s sonar suite is vastly more sensitive and discerning than the lower-fidelity sonar of the spearfish. Should the wire be broken, the torpedo will still continue to search for the target autonomously using the final parameters it was programmed with, and if necessary, its active sonar.
Mod-1 makes increased use of modular components for easy maintenance and replacement and the software is intended to easily accept future upgrades. The warhead is being replaced by a much safer insensitive munition manufactured by TDW that is resistant to shock, blast, heat and fire. The dual-fuel Otto/HAP system that drives the gas turbine engine is being replaced by a single Otto II fuel cell to provide safer, more reliable propulsion.
A final series of acceptance trials included tests at British Underwater Test and Evaluation Centre (BUTEC) in September 2020. HMS Talent subsequently fired four Spearfish torpedoes in February 2021, the first of which was at a targeted vessel. The remaining three were trialled to ensure Spearfish will not attack the launching submarine.
HMS Audacious was deployed to the Atlantic Undersea Test and Evaluation Centre (AUTEC) in the Bahamas to conduct a complex final set of trials. BUTEC and AUTEC are instrumented ranges that are used to test all kinds of underwater weapons and submarines. AUTEC is a sophisticated US Navy facility that the Royal Navy is fortunate to be able to make use of. Deep but protected from the strongest ocean swells and currents by a tongue-shaped reef, it is ideal for torpedo trails. The Tounge of the Ocean (TOTO) is a basin approximately 240 Km long by 30 Km wide as deep as 1,800m in places.
The trials conducted by HMS Audacious included firing five of the weapons over a three day period. This involved tests at maximum operating depth and trials to see how Spearfish responded to countermeasures. Data collected by engineers ashore at AUTEC will be used to further refine its performance.
A further 6-year, £230M Torpedo Repair and Maintenance (TRAM) contract was awarded to BAE Systems in February 2021. This will ensure the availability of both Spearfish and Sting Ray torpedoes and includes repairs, provision of spares, storage and stock management, packaging and delivery and trials support.
Spearfish Mod-1 is probably now one the best heavyweight torpedos in service anywhere in the world and represents the culmination of a large effort across UK industry, DE&S and the navy. It provides the RN with a lethal ship and submarine killer able to resist modern decoys and countermeasures.