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, up and to port from the port side at 65 station showing the mast control valves, pipework and gauges. The 'O' tank trim pump handwheel box is in the centre of the picture. A vertical format negative.