HMS Stirling Castle Minehunting Ship Begins First Voyage Under Royal Navy Command

A specialist minehunting ship has sailed for the first time under the Royal Navy flag after departing Merseyside, marking a new phase in the service’s mine countermeasures operations.

HMS Stirling Castle left West Float, Birkenhead, for sea trials and training four months after being transferred from the Royal Fleet Auxiliary (RFA). The vessel will serve as a floating base for autonomous minehunting systems, operating primarily from His Majesty’s Naval Base Portsmouth.

Formally commissioned into Royal Naval service in July, Stirling Castle was previously operated by the RFA since 2023. Over recent months, the crew of 55 worked with RFA personnel to complete maintenance, safety inspections, and training to prepare the vessel for active operations.

The navy said that the ship will now undergo trials and assessments before moving on to operational sea training later this year. Once fully operational, it will support front-line duties by deploying autonomous surface and underwater vehicles designed for detecting and neutralizing sea mines.

Originally built as the offshore support vessel MV Island Crown, Stirling Castle was acquired by the U.K. Ministry of Defence in 2023 and converted at HM Naval Base Devonport. It served under the RFA for 18 months, supporting minehunting activities and helping the Royal Navy adapt to evolving underwater threats.

As a commissioned warship, Stirling Castle will continue to operate alongside the Navy’s Mine & Threat Exploitation Group, which specializes in autonomous technologies for identifying and destroying underwater hazards. Future plans include repainting the vessel’s current blue and white livery in naval grey.