UK declares IOC for Spearfish Mod 1 heavyweight torpedo

The UK Royal Navy (RN) has declared an initial operating capability (IOC) with the Spearfish Mod 1 submarine-launched heavyweight torpedo.

Announcing the milestone on 12 May, the RN said that work will now begin to upgrade existing Spearfish Mod 0 torpedoes to meet the service’s warstock requirement. IOC was declared after successful firing trials from the Trafalgar-class nuclear-powered attack submarine (SSN) HMS Talent on the British Underwater Test and Evaluation Centre range in early 2021.

Entering service in 1994, the current Spearfish Mod 0 heavyweight torpedo equips all RN submarines, providing them with a capability against both submarine and surface targets.

BAE Systems Maritime Services was in December 2014 awarded a GBP270 million (USD421 million) contract for the Spearfish Upgrade (SFU) programme, which delivers the improved Mod 1 standard weapon to address the need for incremental improvements in safety, the removal of obsolescence, and through-life cost reduction. The modernised Spearfish is intended to remain in service with the RN through to 2060.

Upgrades being embodied in the Spearfish Mod 1 weapon include the introduction of a fully digital weapon architecture (both hardware and software), replacement of the current copper/cadmium wire guidance link with a ruggedised fibre-optic system (reducing the data latency between the platform and the weapon), and the replacement of the existing warhead with an insensitive munition (IM)-compliant warhead. The existing Spearfish Mod 0 hull and Sundstrand 21TP04 thermal propulsion system are retained, although the Mod 1 weapon will transition to a single-fuel propulsion system that will offer cost and safety benefits over the current dual-fuel (HAP-Otto) system.

Following the IOC declaration earlier this year, the Astute-class SSN HMS Audacious