The submarine's attack center, the Conning Tower, is an 8-ft diameter, 14-ft long cylindrical chamber directly above the control room. The conning tower houses both the search and attack periscopes, the main steering station, the firing buttons for the 10 torpedo tubes, the ST and SJ radars, sonar and the electro-mechanical torpedo fire control computer. This computer, known as the Torpedo Data Computer (TDC) is a mechanical marvel. Once it receives information about a target's position and course relative to the submarine, and using information about the submarine's own course and speed, it continuously keeps very accurate track of the relative positions of the two vessels. This function is known as "position keeping". The TDC also computes the course a torpedo from either end of the submarine must take in order to impinge with the target ship at the aiming point if launched at this moment. The aiming information is electrically and continuously transfered to both torpedo rooms and then automatically set into the torpedo's gyroscopic steering mechanism via a mechanical shaft (or spindle) that fits into a lug on the torpedo's side. Just before the moment of firing the spindle is withdrawn from the torpedo so it can be launched from the tube. (Many visitors are surprised to learn that US Navy fleet submarines can fire torpedos in any direction while maintaining a fixed heading.)
Cod's Search Periscope has a wider optical path and larger lenses than does her Attack Periscope. Thus it gathers more light and is useful in dimmer light conditions. It also contains a RADAR antenna in its head. Because of the diameter of the periscope head it makes a noticeable wake in the water even at low submerged speeds. This wake might be easily spotted by lookouts on an enemy ship being attacked from a submerged position. The neck of Cod's Attack Periscope has a diameter of just 1.414 inches, (which, curiously, is equal to the square-root of 2). This smaller diameter allows Cod to move at reasonible speeds while attacking without causing a noticeable periscope wake.
While Cod is at sea, the conning tower is manned by at least four men who stand watches on the radar, sonar and helm (steering station). During a submerged approach on a target the conning tower can be manned by as many as a dozen crew, including the captain at the periscope. Night surface approaches allow the captain to view the targets from Cod's open bridge, directly above the conning tower.
A special ballast tank called the Safety Tank has approximately the same volume as the conning tower, and is normally maintained in a fully flooded condition. If a flooding casualty occurs to the conning tower -- filling it with water -- the 23 tons of water in the Safety tank can be emptied to sea, thus compensating for the extra weight of water in the conning tower. This would allow the submarine to surface so that the hatches on the main deck would be above sea level.
The only armor on Cod surrounds the conning tower to protect it from enemy shell fire when it is exposed on the surface.
The conning tower hatch to the bridge is the only hatch normally high enough above the water to be used while the submarine is at sea and underway.