I think this pic is already in YC/PAS/RMAS. This is the old Research and Development Vessel RDV Broadwey a captured ex German Icebreaker. Could never find out its original name. I was in this vessel during 1964/65 at the Naval Base at Portland She was indeed used by the AUWE(Admiralty Underwater Weapons Establishment). She was four point moored in Portland Harbour along with two others and used as a static but Floating laborotory the black painted projections are Stations that items of equipment were bolted on too and then lowered into the water. These three vessels were finally replaced by a purpose built larger vessel the RDV Crystal during the nineteen seventies which I believe still exists somewhere in the Netherlands?.
The other two RDV's that operated with Broadwey were the Ex Clyde Steamer Duchess of Argyle and former Liverpool Packet Steamer John Farley all converted into laborotories.