Hey Paul,
I suppose we've come to the point where when someone inquires about a "backup GPS", what they really mean is a "backup chartplotter"... (grin)
It's amazing, how far behind the curve I am on this stuff... I was reading an article by Ben Ellison in CW recently about navigation software, it just made my eyes glaze over... I didn't have a freakin' CLUE what it was all about...
I have a couple of old Garmin 48s I use as backups, I always bring one along on a delivery... Early this summer, I ran a Taswell 44 up from Lauderdale to Annapolis... Lots of stuff didn't work, the POS Navman plotter it had was among the non-functional items...
When he learned the plotter wasn't working, I think the new owner just assumed I was gonna run up the ICW... When I arrived in Annapolis, he and his wife were astonished - completely in awe of my skills - that I had managed to find my way north on the outside, relying solely on an "outdated" GPS without pre-loaded charts, and that provided nothing more than one's position, on such a tiny screen... LMAO!
best regards,
Jon