A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the sound room on the starboard side of the main flat between 56¼ and 59¼ stations looking to starboard from the doorway showing 300v and 600v DC units on the left against the forward bulkhead. Against the boat's side are various sonar recorder units, fuse panels, distribution panels and a telephone. Against the aft bulkhead is a large sonar unit. A vertical format negative.