We use the Garmin 76 and it works just fine, even in fog in Maine .
We usually use paper charts , but on the Loop recently there were holes in the chart kit charts.
We downloaded a program and the US gov free charts to iur lap top.
The Garmin would easily give a lat/lon readout and we would scroll that into the lap top and have a "moving map" display with no effort or Co$t.
In Florida where the viz is unlimited , no sweat , but even in the soup in a place like Maine it would work just as well. The fix time to position time is max 10 seconds , no biggie on an 8K cruiser.
And it will work as well with the Loran , if the Chinese EMP the comm & nav birds .
Works for me,