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 to the bulkhead at 62 station from the centre of the port side. In the top left is battery vent fan No. 4 and below it is a pressure gauge above telemotor pump no. 2. In the lower centre is a unit marked 'T.C.S.S. 9 lower cable reel for attack periscope. On the right is the port side D.W. pump discharge. A vertical format negative.