A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the aft auxiliary machinery and gland space (thrust block compartment) between 103 and 107 stations below the main flat. He is looking to port and aft showing the forward end of the stern tube welded to the bulkhead at station 107 with a stern gland assembly attached by a ring of 1 1/4 in. studs and nuts. The turning gear is on the right. A vertical format negative.