The periscope was housed in the centre of the room, with the Ballast pump which was used to extract any water that got into the boat. The base of the conning tower is the Captain's control room. The hatch to the Commander's quarters where he rested. The Hydrolplane controls which were used to control the U-boat when it was diving are on the starboard side. Also visible is the Trimming Station which was used to move water around the boat to keep it balanced, this was also known as the Christmas Tree.