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 up at the deckhead showing the lights and the ventilation openings. Above the door are an intercom loudspeaker, a keel depth gauge, a type 197 sonar intercom mixer unit, a distribution fuse panel for type 197 and 719 sonars, a fan control box and a loudspeaker isolator switch.