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 aft, to starboard and up from the centreline of the main flat at 84 station showing two pressure gauges on the upper part of the starboard 16 cylinder Admiralty Standard Range diesel engine. The larger of the two is a Budenberg differential pressure gauge and the smaller is a standard gauge measuring from 0 to 30 lbf.in². The engine exhaust is wrapped in cladding.