A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the generator room between 77 and 92 stations looking forward, to port and down from the main flat at 82 station showing part of the high pressure air compressor machinery under the main control console between 80 and 81 stations. A fire extinguisher is next to the console. The ballast pump starter is against the forward bulkhead at 77 station.