A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the control room between 59 and 69 stations on the main flat looking aft and slightly to port from the port side at 65 station showing the mast control valves, pipework and gauges. A covered telemotor valve block is at deck level in the foreground. A vertical format negative.