HMS Exmouth was a Royal Navy anti-submarine warfare frigate of the Blackwood or Type 14 class. Exmouth became the first major warship to be powered by gas turbine engines alone when, in 1966, she was taken in hand and was refitted with a combined gas or gas (COGOG) arrangement. The main reason behind the conversion of Exmouth was to trial the (then) new Marine Olympus which had been selected as the turbine for the Type 82 destroyer and the Type 19 high-speed anti-submarine frigate. Therefore, she was fitted with a Bristol Siddeley Olympus TM1 of 24,000 shp (limited to due to gearbox and shaft limitations) for full power and two Bristol Siddeley Proteus 10M (3,500 shp each) for fuel-efficient cruising. These engines drove the single shaft through a common gearbox. The Proteus engines could