You could take this to rec.boats.cruising or rec.boats.electronics.

However, I'm in the same situation (boat) with you. My Ingrid 38 is ~27,000
lbs with tiller and outboard rudder..

There just doesn't seem to be any AP solutions for a boat this size..

Raymarine has recently introduced the " + " and the "GP" units which bring
use to around 20,000 lb.

If your boat is wheel steering and already has hydraulic steering then your
ok. If you have wheel with cable then there are some linear drive units that
will work. If you tiller steering with a rudder stock, below deck, you can
add a tiller arm below and go with the compact elect/hydraulic unit.

However, the hardest steering for a AP will be while the boat is under sail
and it is here that the WindVane could/should be used. IMHO your Cal 39 is
well suited to a windvane. Then go with a lighter, readily avalable AP.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions


"Bill" wrote in message
...
Hi Guys,

A knowledgeable group like this should be able to tell me where to look
,or
what book to buy.

Vessel is a Cal 39 sloop. Displacement ~ 20,000 pounds

Grazie,

Bill