US and UK Navies achieve historic first with torpedo launch from uncrewed submarine

The US and UK navies have successfully completed a historic test under Project Broadsword, launching an American Mk 48 heavyweight torpedo from the British XV Excalibur uncrewed underwater vessel. Conducted in Scotland on September 13, 2026, the trial demonstrated the successful integration of American weaponry with a British autonomous platform, validating interoperability between the two nations' undersea systems. Because the Excalibur lacks traditional internal torpedo tubes, engineers mounted the 3,700-pound weapon externally. This milestone, part of the AUKUS Pillar II framework, highlights the strategic shift toward autonomous undersea warfare and shared mission architectures. Following this proof-of-concept, the US Navy plans to advance integration efforts through Project CUTLASS, which will further explore payload flexibility and operational scenarios for uncrewed underwater vehicles. This collaboration aims to enhance the scale and combat power of allied forces through shared technological standards.