Been using GPS driven chart software on my laptop for 7 years now.
Its reliable enough but only the foolish would take anything for granted when on the water, all circumspect sailors should use at least two independent position fixes systems, as well as their eyes and ears, because instruments alone are the path to certain disaster
There,s a sad story about Jean Socrates who was within a few hours of completing a circumnavigation and ran aground because of, as i understand it, instrument failure. She out again and is some were near the Beagle Channel so it didn,t put her off. Not suggesting she was in any way responsible but the story indicated her boat was on autopilot at the time and she was resting below.
The great appear great because you are on your knees. James Larkin, Irish Labour Movement.