For a long time, GPS has been an integral part of boating. Everything from supertankers to kayaks use GPS for precise navigation, and it would be hard to imagine not having it. Of course, GPS for precise boating is a small niche among GPS users. Newer cars, all commercial aircraft, farmers, the military and hikers all depend on accurate GPS. Over the years, GPS has changed, from government’s intentional error induction (up until the 2000s, but no longer) to the current, far more accurate receivers. Twenty years ago, 100 meters (330 feet) was the best accuracy you could get, and that was only guaranteed most of the time. Now boaters can know where they are, nearly anywhere on the planet, within about 16 feet. Boaters particularly need that accuracy and…