While cruising along the AICW, my C80 chartplotter
started to create problems. I would travel along - using "head up" motion- and suddenly my boat
would show as moving sometimes sideways and sometimes backwards. After ~ 1/2 hour, it would show normal again (head up). This became disconcerting, especially around the "problem areas" of the AICW.
When we bought the sailboat 4 years ago, this problem happened 2 or 3 times and it stopped and behaved normally until this summer. Any thoughts or suggestions?