Spearfish heavyweight torpedo
Overview
The Spearfish is the Royal Navy's heavyweight submarine-launched torpedo and one of the fastest in the world — the weapon of Britain's Astute- and Trafalgar-class attack submarines and Vanguard-class ballistic-missile boats. Its inclusion in an Indo-Pacific reference reflects the AUKUS partnership and Britain's "tilt" to the region: UK submarines now deploy east of Suez, and Australia's future SSN-AUKUS boats draw on a shared Anglo-American undersea ecosystem. Spearfish's distinguishing trait is raw speed. Powered by a Sundstrand 21TP04 gas-turbine engine running on Otto fuel and HAP-Othol oxidiser, it can reach speeds reported above 80 knots — significantly faster than most heavyweight torpedoes — letting it run down fast nuclear submarines and high-speed surface ships. It is wire-guided with active and passive sonar homing and a directed-energy warhead designed to defeat double-hulled submarines. The definitive Spearfish Mod 1 upgrade, now in service, adds a fibre-optic guidance link (replacing copper wire) for far higher-bandwidth two-way communication, an insensitive-munition warhead for safer handling, and improved processing for cluttered littoral waters. For an analyst, Spearfish rounds out the picture of allied undersea firepower in the Pacific — alongside the U.S. Mk 48 and Japan's Type 89 — as the West leans on its submarine advantage to offset China's surface and missile mass.
Deployment Map
Home ports from known hull assignments. Operating areas reflect typical AORs — individual deployments will vary.
Timeline
Specifications
Doctrine & Employment
Role
Royal Navy submarine-launched heavyweight torpedo emphasising very high speed.
Design Philosophy
Speed above all — outrun and overtake high-performance targets.
Employment
Wire/fibre-optic guided with sonar terminal homing; runs down fast submarines and surface ships.
Threat Context
Part of allied undersea firepower projecting into the Pacific under AUKUS.
How to Compare
Read against the Mk 48 (US), Type 89 (Japan) and China's Yu-6.
Operational Patterns
Typical Deployment
Anti-submarine and anti-surface engagements from Royal Navy submarines, increasingly deploying to the Indo-Pacific.
Typical Task Group
Astute/Trafalgar SSNs; Vanguard SSBNs for self-defence.
Readiness
Mod 1 in service; AUKUS commonality growing.
Key Operating Areas
Peer Comparison Matrix
The Mk 48 is more widely fielded with broadband CBASS sonar; Spearfish is notably faster.
Video angle: AUKUS torpedoes — Spearfish vs Mk 48.
Comparable heavyweight role in the allied undersea force.
Video angle: Allied submarine firepower.
China's heavyweight torpedo, the undersea threat AUKUS boats would face.
Video angle: The West's undersea edge vs China.
Combat History
No combat employment; the Royal Navy's standard submarine heavyweight torpedo, demonstrated in SINKEX.
Unproven in war but technically among the fastest torpedoes fielded.
Known Vulnerabilities
Range vs speed
Very high speed comes at some cost to range and noise.
Context: Fast runs are louder and shorter than economical settings.
Mitigation: Variable speed/range profiles.
Countermeasures
Must defeat modern decoys and jammers in terminal homing.
Context: Quiet peer submarines stress the seeker.
Mitigation: Mod 1 processing improvements.
Variants
| Variant | Designation | Years | Count | Status | Key Changes |
|---|---|---|---|---|---|
| Spearfish Mod 0 | — | 1992– | — | active | High-speed wire-guided heavyweight torpedo |
| Spearfish Mod 1 | — | 2021– | — | active | Fibre-optic link, insensitive-munition warhead, improved processing |
Modernization Programmes
Spearfish Mod 1 rollout
Fibre-optic guidance and insensitive-munition warhead across the fleet.
Impact: Higher-bandwidth control and safer handling.
Images
Frequently Asked
When was the first Spearfish heavyweight torpedo commissioned?
The first Spearfish heavyweight torpedo entered service in 1992.
Who builds the Spearfish heavyweight torpedo?
The Spearfish heavyweight torpedo is built by BAE Systems.
What variants of the Spearfish heavyweight torpedo exist?
Known variants include: Spearfish Mod 0, Spearfish Mod 1.
Curated Research
recommended
Fleet context
reference
Speed, Mod 1, platforms
Watch Spearfish heavyweight torpedo in Action
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