The United Kingdom’s multirole ocean surveillance ship Proteus has served with the Royal Fleet Auxiliary (RFA) since late 2023. She is tasked with helping counter the growing threat to vital undersea cables, pipelines, and underwater infrastructure.
The Proteus began life as the commercial support ship MV Topaz Tangaroa, which was designed to operate submersibles and assist with inspections, construction, and maintenance duties in the offshore oil rig industry. She was built in 2019 at the Vard Tulcea shipyard in Romania and fitted out at Vard’s Brattvaag shipyard in Norway. Purchased by the UK Ministry of Defense in early 2023 for £70 million, she was subsequently converted and refurbished at the Cammell Laird Birkenhead shipyard. Renamed the Proteus after the mythical Greek sea god who worked as a nautical shepherd, she officially entered service 10 October 2023 in a ceremony held on the River Thames in London.
The RFA is a merchant navy organization providing civilian-crewed ships that deliver logistic and operational support to the Royal Navy and Royal Marines. In RFA service, the Proteus has been given a new life, helping the Royal Navy and NATO allies protect critical underwater infrastructure. Able to serve as a mothership for a wide array of remotely operated and autonomous unmanned underwater vehicles (UUVs), the Proteus also functions as a floating testbed for new technologies. Her cutting-edge systems, including a multibeam echo sounder and UUVs, help map and monitor the seabed, enhancing the ability to identify and investigate any suspicious irregularities in critical undersea infrastructure.
The crew of Proteus consists of 26 RFA officers and sailors, along with 60 specialized Royal Navy service members tasked with managing the mission-related undersea surveillance, survey, and combat systems.
Carrying pennant number K 60, the Proteus displaces 6,133 tons and measures 322 feet long with a 66-foot beam and 20-foot draft. Her design features a 10,764-square-foot working deck able to handle cargo loads up to 1,400 tons. A heavy-duty 120-ton crane is mounted starboard, near the center of the working deck. It incorporates a 9,800-foot line that permits the crane to deploy payloads onto the seabed at significant ocean depths. A 77.5-foot-squared moonpool is positioned at the forward portion of the working deck, providing undersea ingress and egress points for UUVs tasked with survey, surveillance, salvage, or other subsurface missions.
The hull layout incorporates a sizable internal hangar for UUVs and multiple related workshops along with crew accommodations, galley, cafeteria, lounge, gym, and other creature comforts typically found on board modern naval and commercial vessels. A 66-foot-diameter flight deck sits forward, atop the ship’s bridge, and is able to launch and recover helicopters up to 28,000 pounds.
Five diesel generators power the diesel-electric propulsion system, enabling cruising speeds of 11 knots and a top speed of 14 knots. The ship has two 360-degree azimuth stern thrusters, two bow thrusters, and a retractable azimuth thruster. A specialized dynamic-positioning capability permits the Proteus to remain steady and stable over a precise ocean location as subsea mission requirements may dictate.
