The Spearfish heavyweight guided torpedo is the primary anti-ship and anti-submarine weapon of Royal Navy submarines currently deployed with Trafalgar, Astute and Vanguard class submarines. It weighs two tons and measures five meters in length. Designed by BAE Systems Whitehead Division Spearfish is undergoing an upgrading phase expected to complete in 2020.
Relying on a complex transducer array of active and passive homing techniques to acquire, identify and prosecute naval targets, using advanced beam forming techniques to optimize performance in different environments. According to the manufacturer, the sophisticated acoustic processing and tactical software on board can defeat the most advanced countermeasures. The guidance section located in the mid-body of the torpedo comprises a powerful computer that handles all functions – from propulsion to homing, and attack techniques.
Spearfish swims toward its target while linked to the submarine via wire link, that exchanges commands and target data over long distance. In a typical engagement, Spearfish will run out of wire in the general vicinity of the target where it will conduct a covert passive search to acquire the target for the final phase. Spearfish can also operate autonomously from the time of launch.
Its propulsion system is based on a gas turbine with pump producing variable speeds across the entire performance envelope, including a fast sprint in the terminal stage of an attack. At full speed of 80 knots the Spearfish can strike targets at a range of 14 miles, and, at low speed, it increases the range to more than 30 miles.
Once at the close range, the torpedo accelerates to sprint speed and 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 maneuvers. Should Spearfish fail to hit the target on its first attack, it automatically selects an appropriate re-attack mode to conclude the engagement. The warhead has the lethality against double hull submarines and large displacement surface ships; it is programmed to detonate on impact, or by a proximity fuse when the torpedo passes under the target’s hull.
The weapon is currently undergoing an upgrade that improves its homing, warhead and tactical systems. The copper wire data link will also be replaced by fiber optical link. According to BAE Systems. The upgrade will also single fuel system, and the 660 lb warhead will be made of insensitive munition for additional safety. The upgrade will also to incorporate the latest developments in sonar technology, and introduce re-programmable software technology enabling frequent updates based on intelligence on the evolving threat characteristics. The fleet will begin receiving the improved torpedoes by 2020 and complete the upgrade in four years.