Deviation, Variation and Heading Offset

[bob423]

I have the 2004 set of Raymarine autopilot instruments for my Beneteau 423 sailboat with the autopilot head replaced with a p70. When I do the circles for calibration, everything is fine for a day or so but then the heading flips 180 degrees. It doesn’t seem to affect performance of the autopilot and I’ve lived with it for years.

However, I’ve recently installed a Vesper XB-8000 AIS transreceiver and it uses the heading to set the boat icon orientation. When displayed on the AIS of other boats, I appear to be going backwards.

Is there any way to just manually adjust the heading to any value I want, even 180 degrees off?

Instruments
Autohelm 6000
p70 head
ST60 compass
Chartplotter RI70CRCplus

Thanks, Bob423