The challenge is finding a reasonably priced actuator that has the speed and the strength to move your rudder in all, or at least most, sea states. Higher winds and sea states tend to really test the autopilot, and in particular the actuator. The problem is that the lever arm from the rudder post to the outside of the quadrant just isn't that long, so the forces there tend to be pretty high - much higher than required if the boat was tiller steered.
In my case, my boat came with a Raymarine autopilot already installed. The actuator for it is pretty large, as is the wiring going to the actuator from the control box. You also, obviously, need to think about how waterproof it all is.
I suggest looking around Ebay or something like that for a good used actuator from an autopilot. Here's an example: https://www.ebay.com/itm/Furuno-Auto-Pil...Sww5Zdil-M
Here's the specs on my actuator. Note the speed of operation (1.2in/sec) and the force capabilities:
https://www.dropbox.com/s/zalsdvyde5ab2t...t.jpg?dl=0
In my case, my boat came with a Raymarine autopilot already installed. The actuator for it is pretty large, as is the wiring going to the actuator from the control box. You also, obviously, need to think about how waterproof it all is.
I suggest looking around Ebay or something like that for a good used actuator from an autopilot. Here's an example: https://www.ebay.com/itm/Furuno-Auto-Pil...Sww5Zdil-M
Here's the specs on my actuator. Note the speed of operation (1.2in/sec) and the force capabilities:
https://www.dropbox.com/s/zalsdvyde5ab2t...t.jpg?dl=0