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 from the main flat at 78 station showing the main console desk in the right foreground and the two 16 cylinder Admiralty Standard Range diesel engines on either side of the walkway. The ladder up to the escape hatch between 90 and 91 stations is in place. A vertical format negative.