A 2¼ square film negative. The Type 12 frigate Yarmouth (1959) in a dry dock in Portsmouth Dockyard. A close view of the Type 174 Hull Outfit 20 sonar dome partially lowered between 15 and 19 stations. The canoe, which is the lower section of the dome, has been removed to enable work to progress on the transducer. The photograph is taken from the bottom of the dock looking to port.