Use GPS, its not my boat I didn't pick out the electronics.
Even GPS has its issues in the more remote parts of the world it seems. According to an article in the latest issue of cruising world a boat that was going around the horn had a bunch of trouble with there chart plotter as they got further south. For example it would be telling them an inlet is on port, but the radar would be telling a very different story.
Then they would pull out the charts that were last updated in 1841, fun stuff!
