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 mortar handing room between 67 and 71 stations on the port side of 2 deck looking aft on the port side showing the battery stowage unit with the charge unit above it and the contact heater transformer against the ship's side. The depth setting control panel and a resistance box are against the aft bulkhead. The end rammer chain motor is on the left. A seaman can be seen on the quarterdeck beyond the open door to the handing room. A vertical format negative.