Mate, we have the same instruments, and same problem - although our instruments are a little older than ten years. And ours actually alternates with the wind
guage - they take it in turn to work correctly!
It's not fouling, and it's not wiring
. It's plain old old age. Throw the thing if you need reliable instruments. We keep ours cos we have a perfectly good wind vane
(for when the wind
instruments go) and an awesome new sonar depth sounder
- so we keep the old instruments around for a laugh. And the speed thing still works - and we need that to record
the max speeds for each helmsman on each voyage. Not that it's a race
, of course. Not at all.
Oh, and the autopilot
is fun too. It reads about a hundred degrees out, and won't be realigned no matter how carefully we follow the instructions. But it still holds a good course... so long as you can accept that it won't read the same number as on the GPS!!!