Garmin problem

[Longbranch Louie]

Twice while in thick fog our 700 series Garmin with upgraded chip suddenly fails to tell us which way the boat is heading. Even with a drastic change in course it wont show the change until I have way over corrected and it then shows Im headed in the wrong direction again. Its like its lost its compass. The first time I blamed it on slow speed and rip tides but this time it was in calm (foggy) waters at 7 knots. The boat icon show any change. I had moved off a course line (no auto pilot) to steer clear of a ferry lane, and had great difficulty steering back towards the prescribed course as nothing on the plotter indicated I had changed direction even though my magnetic compass showed over a 45 degree change. Are these limited in overcast or foggy conditions? Am I doing something to confuse it? Ideas? With the small screen garmin I usually zoom in while using radar to see targets better. This further limits me seeing my overall position on the chart. using a split screen radar/chart combo makes things pretty small. The unit appeared to show my correct position on the chart it just wouldn't show direction of travel until too late.

 

[RProffer]

The first thing I would do is reinstall/update the software. That seems to fix the gremlins on Garmin's. I recommend carrying a USB drive with you on the boat in case something happens and you need to reinstall. My Garmin appeared to die on me when we were out one day and reinstalling the software fixed it. I also recommend having some backup software like Navionics installed on your cell phone as a backup.

If reinstalling the software doesn't fix it, I would give Garmin a call. That is a serious problem.

 

[Levitation]

If you are totally dependent on the one MFD for navigation then you had best have a back up.
Either a hand held or a second unit.
I mounted a 740S on top of the helm instrument panel. The newer version (741xs) just came out so the 740S is heavily discounted - and used ones are showing up .

 

[Longbranch Louie]

We have navionics as a back up most of the time (it helped us the first time) and a hand held Garmin too but I needed radar too in the dense fog and it was troublesome not knowing if I was seeing my position correctly in relation to the radar contacts, or if I was steering a course away from them.

 

[Levitation]

With a 740 you can swap the radar cable over to it.
Lots of ways to solve the problem.

Or, a lead line and a chart? :mrgreen: (Mark Twain)