It's actually a bare bones simple unit. It has two units- a compass with "reed" type relays on top of it. A cable runs from the rudder arms aft to where the compass is located. So you can "chase" from the cable forward to where the compass is. Lift the blue-green can off the compass and there it sits, with the little reed relays exposed. They are sealed, so should not corrode easily.
How it works: As the boat changes direction, the compass turns as well, and the reed relays make or break, as you turn away from your original heading or return to it. The reed relays are "over", i.e. turn on or off very simple good old fashioned diodes, aka, transistors. NO microprocessors and their extremely long life (not) to deal with. Transistors you should be able to get forever. The transistors are housed in a grey box in the engine room about
8"Hx12"Wx8"Deep.
When the reed relay calls the transistor (turns it on), the transistor runs the rudder pumps to turn the rudders and bring the boat back to its original heading. The rudder pumps are probably next to the power (transistor) unit and the pump and motor are mounted on a steel block. When the turning is complete, the reed relay will turn back off, the transistor turns off and the pump stops and the rudder stops amidships. The hydraulic pump setup is standard on all modern autopilots; that much has not changed.
I had a fairly young (to me that would be an early to late 40's) fully ABYC certified tech tell me that they are or seem more gentle that the modern units- no so abrupt. Truth be known a compass will always "work", whereas GPS can go out (the satellites can down too).
So to use the WF unit, turn it on, and "set" the heading, i.e. do nothing. The autopilot assumes you wish to go in a straight line (lol)! The relays assume straight ahead is your desire and are fixed in position. There is a small adjustment on top of the compass so you can fine tune just what "straight ahead" is for your boat. Have someone steer steady as she goes ahead and fine tune the compass.
The relays on top of the compass mechanically align with the heading. When the heading changes, they engage, sending the boat back to the original heading, then they turn off. There are two buttons on the small W-F panel. Press the left black button and it will take/turn you left, while the right button takes/turns you right. This allows minor course changes When you release either button, the AP will return to straight ahead steady as she goes on the new heading. Like I said, simple.
There is still a WF repair and rebuild site out West on the Coast, up north- they answer the phone; another modern shock. Google about WF and a very nice site resiting the history the WF autopilot comes up. She was designed by a sailor, after he fell and broke a leg while single handling, so she will guide a sailboat as well.
Usually, what goes wrong is one of the transistors goes out and does not respond when called by the reed relays.
All I know.
