Just to add to Bob's excellent response, I might add some information regarding our current steering setup.
Although 325 has a hydraulic system for conveying the steering commands to the steering gear, it is simply an interfacing arrangement that eventually turns on electric switches in the steering compartment which activate the DC electric winch motors that run the cables to the rudders.
During the voyage from Crete when the crew found the steering to be hard to manage, the electrician(s) substituted a rotary switch for the helm (on the bridge)
and ran an electric cable down to After Steering to directly control the winch motors, thereby eliminating the hydraulics with it's possible leaks or air bubbles.
This is the system in use ever since, and has been augmented (for the Pilot's sake) with a Joystick (switch) located in the Conn.
One wonders why the hydraulic system was used in the first place? Was it more "battle hardened" than the armored electric cable? Was it a carry-over from older systems and used just because it had a satisfactory track record?
(BuShips was prone to do a lot of this in all areas of shipbuilding during the first years of WW2 for time saving, since the previous manufacturing arrangements had already been in place; as opposed to trying new technologies that would have taken longer to implement)
One of many interesting bits of Trivia for us to mull over in our spare time.