A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the auxiliary machinery space between 62 and 68 stations below the main flat looking forward and down at the starboard side of the bulkhead at 62 station showing a gauge which is labelled No. 1 pump discharge pressure and a 10" x 6" battery vent fan No. 3. An electric motor is on the right. A vertical format negative.