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 crew accommodation space between 103 and 117 stations on the main flat looking forward and to port into the corner at 103 station behind the CO² absorption unit showing 11 valve handwheels of an hydraulic system on the forward bulkhead. They are of the five hole perforated type; six of them are light coloured return valves and five are dark coloured pressure valves. Against the port side of the boat are eight solid valve handwheels. A vertical format negative.