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 forward on the starboard side showing the door from the auxiliary machinery compartment with the gyro compass master unit next to it. Above the master unit are three test sockets and an E.M. log probe connection box and to the right is the gyro compass circuits junction box No. 1. Cupboard three is against the starboard bulkhead.