"Wayne.B" wrote in message
...
On Mon, 18 Sep 2006 13:49:01 -0400, "Gerald"
wrote:

I suspect this really requires the use of a gyro compass
to get a sufficiently stabilized overlay. I had a gyro on my last boat
and
it made a big difference in ARPA accuracy.

Not really. I have an electronic compass sensor and it works just
fine for both ARPA and chart/radar overlay.

Interesting. Actually, the Gyro was part of the KVH TracVision system.
Extra output port allowed it to interface with the radar. The Fluxgate I
had did not respond fast enough to keep up with rock'n and roll'n in any
kind of seas, the Gyro did much better. New boat will not have KVH so maybe
the electronic comass will do the job. Thanks for the input