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 on the main flat looking aft and to port from the walkway at 92 station showing the battery charging control panel, manufactured by John I Thornycroft & Co Ltd, with three low power motor generator starter units above it. Two fire extinguishers and two distribution boxes are on the end of the low power control panel. A vertical format negative.