How does an autopilot work?

[Des_Beechey]

On the boat I have bought there is a Cetrek 707 Powerhelm auto pilot, joined into the hydraulic steering. I have been operating it in what they call AUTOPILOT mode, where it is NOT connected to the GPS. In this mode, it just steers on the heading you tell it to. But it doesn't seem to do it very well. Can anyone tell me how an autopilot maintains course in this mode? Does it just look at the electronic compass now and then, and change back to the correct heading if off course? What happens if the boat has been carried sideways by wind or tide?

Des Beechey

 

[hlb]

In auto mode it will just try to follow the direction you have set but cannot take acount of drift ect.
They can ussualy be set to give different responces which should give more accuracy.
Far better to conect it to GPS and put a course in.
Then it will track the course and keep the boat accurate to within a few feet of that course, providing that the boat has enough power to enable it to do that.
Of course if the drift is greater than the speed of the boat the auto pilot will just give the message OFF COURSE and hand the problem back to you.

Haydn