Thanks ... yes that was the first thing we checked for (stray fields) It worked fine on a previous trip to the fishing grounds then at the days end we picked up to head in and I observed it going “bizzarro” it was showing NE when I was heading WSW all the while slowly rotating. When we docked the boat the damn thing was still rotating back and forth 60 degrees. I had my electronics installer look at it later in the week during an auto pilot install and he was stumped too.Have you installed anything electric recently?
Next time the compass gets wacky, turn off everything and see if the compass settles down. ( By everything, I mean the battery switches. In addition, if you put store you phone or tablet or other device near the compas, try moving that device. The compass could be shot but it could also be effected by stray fields.