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 to port and aft from the main flat at 80½ station showing the forward end of the port side 16 cylinder Admiralty Standard Range diesel engine. The instrument panel is above a mass of pipework and valves. Temperature gauges are fitted to each cylinder and a gauge showing the keel depth in feet is on the left. A vertical format negative.