A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the auxiliary machinery space between 62 and 68 stations below the main flat looking towards 65 station at the centreline and down from the starboard side showing the four gauges which are labelled No. 2 battery cooling pump suction, No. 2 battery cooling pump discharge, No. 1 battery cooling pump suction and No. 1 battery cooling pump discharge. Two gauges in the lower right are marked No. 1 pump suction line pressure and No. 1 pump casing pressure. A vertical format negative.