A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the motor room between 92 and 103 stations below the main flat looking to starboard from the centreline at 96 station showing No. 1 225v 100KW motor generator set with lockers L13 and L14 above it on the left and the forward end of the starboard main motor on the right. Locker L20 is against the starboard side of the boat.