What happened at Atlantic Thunder 26: US-UK live-fire SINKEX sinks ex‑USS Klakring

# Quick summary

# Timeline and purpose

• Sept. 10: Pre‑sail conference at Faslane, Scotland, to prepare combined forces.
• Sept. 14–25: Multi‑axis, long‑range maritime training involving surface, subsurface and air units.
• Sept. 25: SINKEX that sank the ex‑USS Klakring.

Commanders described the program as aimed at improving interoperability between U.S. and U.K. forces, exercising information sharing and testing weapons systems and targeting networks across domains.

# What was tested and how The exercise mixed joint air and surface strikes with subsurface fires. Participating units included:

• Royal Air Force and U.S. Air Force aircraft.

Officials said the exercise included tests of weapons systems and the networks that tie sensors and shooters together. Unmanned underwater vehicles were also part of the operation: U.K. UUVs dived to scan the seafloor to assess damage and to exercise unmanned sensing at depth.

Public statements and follow‑up reporting note that the submarine USS Massachusetts struck and sank the target using a Mk 48 heavyweight torpedo. Other strike elements reported in coverage included surface and air munitions directed at the target during the SINKEX.

# The target ship: ex‑USS Klakring

• Decommissioned in 2013 and laid up in Philadelphia before being towed to Scotland for the exercise.

# Location and conditions

# Notable technology and concepts exercised

• Multi‑domain targeting and information sharing between U.S. and U.K. forces.
• Integration of unmanned underwater vehicles into deep‑water targeting and assessment tasks.
• Combined use of air, surface and submarine weapon systems in a coordinated SINKEX.

# Immediate outcomes and next steps A full public report was not released at the time of the exercise. Statements promised additional details on test results to be published later, particularly on the UUV data and how sensor networks performed during the joint strikes.

# Bottom line Atlantic Thunder 26 was a concentrated interoperability and weapons‑integration exercise that culminated in a live‑fire SINKEX. It combined traditional platforms and emerging unmanned systems to test how allied forces coordinate strikes and assess damage in deep water.