A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the control room between 59 and 69 stations looking to starboard from 65 station showing the echo sounder recorder on the right with type 183 or 185 sonar units below it. The hatch leading down to the auxiliary machinery compartment is in the foreground with main tank vent valves against the starboard side of the boat. An automatic emergency lantern and a battery of switches are on the left. A vertical format negative.