A 35mm roll film negative. On board the Rothesay class type 12 frigate Rhyl (1959) in Devonport Dockyard. In the conversion machinery room on the starboard side of 3 deck between 31 and 35½ stations. The photographer is looking aft on the starboard side of the room showing a large rectifier and two searchlight rectifiers on the left. A motor generator is on the right and on the aft bulkhead is a control board. The photograph was taken prior to 9 May 1972. A vertical format negative.