Converted OSV Enters Service in the UK as an Underwater Surveillance Ship

A converted offshore support vessel has taken on a new life as a dedicated underwater surveillance ship for the U.K.'s Royal Navy.

Christened during a ceremony in London on October 10, RFA Proteus will be operated by the Royal Fleet Auxiliary as a launchpad for remotely operated underwater vehicles (ROV) and a home to a suite of specialist capabilities similar to those found in the offshore oil and gas industry.

The ship, built in 2017 as a subsea construction vessel named Topaz Tangaroa, was acquired by the U.K. Ministry of Defense in January and converted at Cammell Laird for its new role as a Multi-Role Ocean Surveillance Ship (MROSS). Proteus is equipped with a flight deck and a 1,000-square-meter cargo deck, plus a heavy-duty crane for lifting and lowering operations.

The 6,000-tonne vessel left Merseyside in September to undergo trials and training off Portland before heading to London for its official entry into service.

The ship is crewed by 26 Royal Fleet Auxiliary officers and sailors, augmented by 60 Royal Navy specialists responsible for the undersea surveillance, survey and warfare systems. The U.K. will also use the ship as a testbed for advancing science and technological development.

Proteus is one of two vessels acquired by the MOD in an effort to better protect seabed telecommunications cables and oil and gas pipelines amid ongoing war in Ukraine.

“It is paramount, at a time when we face Putin’s illegal invasion of Ukraine, that we prioritize capabilities that will protect our critical national infrastructure,” U.K. Defense Minister Ben Wallace said earlier this year.  

The second vessel, RFA Stirling Castle—another former offshore support vessel, previously named Island Crown—underwent modification to become a mother ship for crewless minehunting systems.