A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the motor room between 92 and 103 stations below the main flat looking aft from the centreline between the main motors at 100 station showing the valves and gauges on the aft bulkhead at station 103. These are the controls and gauges for the A.L.K. winch and some of the valves are marked 'non-return and throttle valve', 'shuttle valve' and 'cable cutter rotary stop valve'. A vertical format negative.