Originally planned for May, exercise Atlantic Thunder 26 will now go ahead in September after a four-month delay. The exercise will test allied weapons, targeting networks and uncrewed systems in a demanding live environment.
Taking place in waters off the QinetiQ Hebrides range in north-west Scotland between 17 and 21 September, AT26 is officially described as a “multi-domain exercise designed to validate surface weapon kill chains, build resilient kill webs and deliver strategic messaging through kinetic demonstration”. Its centrepiece will be a sinking exercise (SINKEX), with British and American air and naval forces conducting coordinated attacks against the decommissioned Oliver Hazard Perry-class frigate, USS Klakring.
A similar exercise was carried out in September 2022 when the former USS Boone was sunk off Scotland by a combination of Harpoon, Martlet and SM-6 missiles together with bombs launched from RN, RAF, USN and UASAF platforms. USS Klakring was decommissioned in 2013 and has been stored at the Philadelphia Naval Inactive Ship Maintenance Facility (NISMF) since. She was towed down the Delaware River on 12th August in preparation for the voyage across the Atlantic, initially to Campbeltown.
Taking place in waters off the QinetiQ Hebrides range in north-west Scotland between 17 and 21 September, AT26 is officially described as a “multi-domain exercise designed to validate surface weapon kill chains, build resilient kill webs and deliver strategic messaging through kinetic demonstration”. Its centrepiece will be a sinking exercise (SINKEX), with British and American air and naval forces conducting coordinated attacks against the decommissioned Oliver Hazard Perry-class frigate, USS Klakring.
A similar exercise was carried out in September 2022 when the former USS Boone was sunk off Scotland by a combination of Harpoon, Martlet and SM-6 missiles together with bombs launched from RN, RAF, USN and UASAF platforms. USS Klakring was decommissioned in 2013 and has been stored at the Philadelphia Naval Inactive Ship Maintenance Facility (NISMF) since. She was towed down the Delaware River on 12th August in preparation for the voyage across the Atlantic, initially to Campbeltown.
Environmental regulations demand that potentially hazardous materials are removed from vessels that will be deliberately sunk, which can be a costly process. This does not fully explain why former USN vessels are being towed across the Atlantic rather than using one of the very plentiful decommissioned RN warships. Hulks are not something the RN is currently short of, as there is an ongoing procession of decommissioned Type 23 frigates being towed to Turkey for scrapping at regular intervals. HMS Monmouth was first to go in April 2025, HMS Westminster was towed out of Portsmouth in July and HMS Northumberland will depart in September.
The RN conducted a Fleet Weapons Trial of the Naval Strike Missile in September 2025 when HMS Somerset launched one at a land target in Norway. The RN possesses a limited number of NSM delivered directly from Norwegian Navy stocks and fitted to HMS Somerset, Portland and Richmond. (HMS Richmond has now been decommissioned). Firing one of these precious weapons is therefore unlikely. Further deliveries of NSM, which are in very high demand globally, from the manufacturer Kongsberg are expected in the future. It was announced as far back as November 2022 that 11 escorts would receive NSM. With the frigates force declining more rapidly than expected, 11 is now the total number of frigates and destroyers currently left in commission. In typical fashion, equipping the fleet with this important weapon has been glacially slow and none of the destroyers appears to have received the mounts so far.
Sea Venom reached Initial Operating Capability (IOC) in May 2025, in time for deployment with the Carrier Strike Group on Operation HIGHMAST, although the milestone was not publicly announced until October. Although MBDA have test-fired the weapon during development, if the RN has launched the weapon in trials, it has not been made public. AT26 may provide an opportunity for a Wildcat helicopter to conduct the RN’s first live firing. Sea Venom was primarily conceived for use in complex littoral environments, rather than in open ocean against large warships.
AT26 will also involve experimentation with maritime uncrewed systems employed for target acquisition and remote underwater survey of the wreck. The Klakring will go down in deep waters off the continental shelf and the hulk is expected to settle at a depth of more than 1,900 metres. The RN plans to use UUVs to conduct surveys of the wreck, gathering high-resolution imagery and data to evaluate the effectiveness of weapons and the potential of new survey technologies. This will also serve to advance concepts of interoperability to interchangeability with the USN in uncrewed underwater operations. AT26 is not simply a demonstration but a development exercise for emerging technologies.
For the RN, the exercise provides an opportunity to showcase allied strike power while at the same time progressing uncrewed systems development in a demanding live environment. For the USN, it continues a tradition of large-scale SINKEX events as a means of validating combat effectiveness and sending a clear message of deterrence.
Main image: USS Klakring towed down the Delaware River on 12th August (Photo: Al Stinger).
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