Royal Navy's XLUUV Excalibur Fires Torpedo in AUKUS Trial
The Royal Navy's uncrewed submarine XV Excalibur has successfully launched a US Mk48 torpedo off Scotland, a first for AUKUS Pillar 2 aimed at advancing
The Royal Navy launched a torpedo from the uncrewed submarine XV Excalibur for the first time during a trial off the northwest coast of Scotland. The three-week experiment, part of AUKUS Pillar 2, saw the Extra-Large Uncrewed Underwater Vessel (XLUUV) fire a recoverable US Navy Mk48 Mod 4 heavyweight torpedo near the Kyle of Lochalsh.
This successful weapons trial, codenamed Project Broadsword or Trial Iron, represents a leading operational milestone for the AUKUS partnership. British and American teams, supported by industry, delivered the credible fighting capability in just six months. The goal is to provide the three allies with an uncrewed system for undersea warfare without risking personnel.
Vessel and weapon specifications align with operational goals
The experimental XV Excalibur is a 12-metre vessel displacing 19 tonnes. From this platform, it launched the Mk48 Mod 4 Heavyweight Torpedo, a weapon designed to destroy adversary submarines and warships.
| Specification | XV Excalibur (XLUUV) | Mk48 Mod 4 Torpedo |
|---|---|---|
| Length | 12 metres | Nearly 6 metres |
| Weight | 19 tonnes displacement | Over 1.5 tonnes |
Neither the torpedo nor the XLUUV were originally designed for this deployment method. The Mk48 is already in use with half a dozen navies around the world.
Trial advances AUKUS Pillar 2 undersea warfare objectives
The test is the first in a US-initiated series aiming to field torpedo-launching uncrewed vessels globally under AUKUS. AUKUS Pillar 2 focuses on rapid capability development alongside the pact's separate goal of acquiring nuclear-powered attack submarines for Australia. The tests will gradually increase in scope and complexity.
General Sir Gwyn Jenkins stated, "These trials mark a pivotal moment for AUKUS and show what the UK, Australia and the United States can achieve together." The trial was completed by the Royal Navy in conjunction with the United States Navy, achieving a milestone in autonomous warfare.
Industry and naval teams delivered rapid results
The trial was directed by UK trial director Lieutenant Commander David Iwanek and is believed to have taken place at the British Underwater Test and Evaluation Centre (BUTEC). Industry partner MSubs built the XV Excalibur, while QinetiQ operates the BUTEC range where the trials occurred. The Submarine Delivery Group Autonomy Unit, which is part of the UK’s Defence Nuclear Enterprise, was involved.
Lieutenant Commander David Iwanek said the achievement paves the way for a step change in underwater lethality. The series of trials initiated by the United States will increase in scope and complexity to eventually field torpedo-launching uncrewed vessels globally.
