On board the Type 12 general purpose frigate Plymouth (1959) alongside the south side of number 3 basin in Chatham Dockyard at the end of a modernization which commenced in August 1966. The ship is berthed starboard side to the quay. The photographer is in the sonar control room between 35 and 39 stations on the starboard side of 1 deck looking into the starboard aft corner showing a range and bearing console, a pitometer log speed indicator, an asdic type 177 junction box, a torpedo warning and H.E. relative bearing junction box and an intercom, telephones and interphones junction box. A vertical format negative.