On Tue, 18 Nov 2003 11:08:14 -0500, "Armond Perretta"
wrote:

Rodney Myrvaagnes wrote:


If all you need is to hold a straight line, you don't even need to
hook up the NMEA. The autopilot will follow the magnetic course you
start it on with its internal fluxgate compass.

I will pick nits here, Rodney, but mostly semantic nits. The idea behind
the NMEA autopilot interface is to have the vessel _maintain_ a straight (or
more accurately rhumb) line course. If the autopilot is set merely to
follow a magnetic compass course, then the resultant track will be at the
mercy of currents, wind, leeway, etc.
.
You are right, of course, and that is why I intend to hook up the NMEA
next spring. But my old autopilot, which had no such facility, could
hold a fairly straight course in motoring conditions for a few hours.
Until it gave up completely.


Rodney Myrvaagnes J36 Gjo/a

The meme for blind faith secures its own perpetuation by the
simple unconscious expedient of discouraging rational inquiry.
- Richard Dawkins, "Viruses of the Mind"