A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the gyro compass room between 65 and 68 stations below the main flat, looking up towards the aft starboard corner showing a periscope heated windows dual control unit on the left above the gyro compass electrical circuits junction box 10. On the right is the ship's speed retransmission unit above an inverter heater unit. A vertical format negative.