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 aft and to port showing the port propeller shaft and the forward end of the stern tube is welded to the bulkhead with a stern gland assembly attached by a ring of 1 1/4 in. studs and nuts. The turning gear is in the right foreground.