A 2¼ square film negative. The Type 12 frigate Yarmouth (1959) in No. 2 dry dock in Rosyth Dockyard. A very close view of the port side fairing blocks of the dome of Hull Outfit 20 Type 174 sonar between 15 and 19 stations. The blocks are labelled MOD.1 Patt No. 192732 Block No. 2 and MOD.1 Patt No. 192733 Block No. 3. The photographer is on the floor of the dock looking to starboard and slightly aft.