In s.com Howard Peer writes:

Steve wrote:
Yes, this has been done by a few with some success.

Most use a small tiller pilot and attach it to the pivot hinge device where
the normal wind sensor vane 'would normally be'. (it won't work properly
unless you remove the wind sensor vane.)

I have tried it on my Aries windvane but it wouldn't work while motoring
because of the proximity of the Aries servo rudder to the trailing edge of
my stern mounted main rudder. The prop wash coming off the rudder varied
considerablily as the main rudder shifted to correct the boat course. This
prop wash just drives the servo rudder 'hard over'.

I have experienced this same problem while trying to use the windvane, in
it's conventional mode, while motor sailing.

If you have an inboard rudder, I don't think you will have any problems, as
I have discribed. I would suggest that the windvane servo rudder should be
in relatively calm wake.


Peter Förthmann mentions doing this in his book "Self Steering Under
Sail" The book address both auto-pilots and wind vanes and discusses
how to use them in combination. The book is available as a free PDF
download at the following URL.


http://www.windpilot.de/en/Se/Service/downen.html


It is possible to use an autopilot in the place of a windvane for most
wind steering gears. Sometimes one should remember the first (often
forgotten) law of mechanical engineering: Keep it simple, stupid. Often
abreviated: KISS.

If there is enough wind for the windwane to work, there is no reason to
rig another electronic device to do the job. If you are motoring, you do
not have to save electricity and you can use the autopilot, but in most
cases the autopilot can do the steering by itself, without the necessity
to rig the wind steering gear.

Some people just try to solve problems that do not exsist by making
things more complicated. Of course we still could have a wind
instrument, steering the autopilot, steering the wind steering gear...

Just another point: If you want to have a backup for your windvane, do
not buy something small, but buy one that can really steer your boat.
Rather have two systems, independent of eachother so you can use any of
them anytime you want.

- Lauri Tarkkonen