LarryR wrote:
My big
concern is the heading sensor. I have a steel hulled sailboat and I am
told a flux-gate compass does not function well inside a metal boat.
My Simrad autopilot system produces a 10Hz NMEA signal, but pulls it
from a traditional compass. I am not sure if this will give an
adequate update of my heading to have a stable radar image.

If it's 10Hz that's as quick as any of the other compasses send out
data, and plenty fast enough. Whether the heading data it reports has
the desired accuracy is up to you.

My shot would be to give it a try first; you can always throw more money
at the problem later.

Note that you should give the fast heading data a separate serial input,
as it's likely to overwhelm other data if you try to share it using a
NMEA multiplexer (this happened to me).

You can also read the newsgroup hosted by Nobeltec itself at
news.nobeltec.com; plenty of independently minded folk can be found there.

Kees