Did you Google "sailboat self steering"???

Lots of pertinent hits. There's also a neat book on setting up various
arrangements after you map the transfer function (helm to heading) for your
boat.

Unfortunately, most of these are for tiller systems and are related to
keeping a heading while under sail. If you are wanting to steer in a calm,
you'll need a heading sensor; gyro or mag compass. (or a very stable boat)

A friend was into homebuilt autopilots for his experimental aircraft. For
heading change he put an optical sensor on the edge of his gyro compass (see
eBay for directional gyros). He sensed pitch and roll with puffs of air
which traveled up between four temperature sensors (thermistors) and
generated differential cooling if the aircraft moved as the puff traveled
past (a NASA scheme). You might send the air puffs horizontally to give a
heading change rate? His puffs were generated with a small air pump, but he
was converting to a speaker generated puff when we last discussed it. The
system flew as well as the costly commercial units. Of course the actuator
is tough. As an alternative to moving the wheel, you might consider a trim
tab since you're talking short term use.

Roger

http://home.insightbb.com/~derbyrm

"ray lunder" wrote in message
...
Any pictures or ideas out there for a homemade autopilot for a medium
weight 23' sailboat? This has wheel steering. I'm thinking of when
there's no wind and you want to maintain a course for a few minutes to
hand sail or tidy up.
Did you know there's a band called autopilot? Isn't google great?