A roll film negative. On board the Tribal class type 81 frigate Mohawk (1962) in Portsmouth Dockyard. She was in a dry dock from 21 March to 11 April 1972 when she moved to the South Railway Jetty. In the sonar instrument compartment between 16 and 27½ stations on 3 deck. The photographer is looking aft and to starboard showing four racks of electronic equipment, including two items that are labelled as 3000 volt units. A vertical format negative.