Wikipedia:
In January 2023, the first vessel for this role - MV Topaz Tangaroa - was acquired and is to enter service as RFA Proteus. She was purchased for some £70 million and is to be converted to act as a mothership for autonomous systems and have military communications and light defensive armament added. The vessel ship is described as having been built in 2019 and is equipped to operate autonomous submersibles. She has diesel-electric propulsion with powerful twin bow thrusters to "hold a precise stationary position when working over subsea installations". She is also equipped with a ‘moon pool’, permitting a sheltered way for robot submersibles to be launched or recovered in high sea states. The ship is 98.1 metres-long with a flight deck, heavy duty crane and 1,000 square metres of cargo space. It is reported that a second MROS ship is envisaged, which is to be a new build vessel and as of 2023 is in the concept stage.