"A Celestial Fix on lake champlain will put him somewhere in the adirondacks..since it is pretty darn hard to get a horizon there!!"
In Labatts case, yes carry an extra on board, maybe just a nice handheld with all the bells and whistles. But, I have seen screenshots of a chartplotter showing some boat to be about 300' inland when they were actually tucked safely in the slip, so GPS isn't foolproof. Sorry about not knowing Labatts cruising area.
However, where is Maddata sailing when his GPS turns into a field improvised doorstop? Half way to Bermuda maybe???? I don't know. All I'm saying is that the Polynesians didn't settle the south pacific by carrying extra GPS units with them. Magellan didn't get where he was going by having the latest toy loaded with his favorite tracks and waypoints.
Sorry for hijacking the thread, hope someone can help you guys with the technical problems.