I just have to ask what is probably a dumb question, because somebody has now told me that GPS is not very accurate for determining your speed on the water. If not, why not? Does its relative accuracy have to do with how much distance you cover while taking the readings...or what? Is it likely to be more reliable at slow speeds than at fast speeds? And if GPS is not a reliable indicator, what would be a better way of determining your speed while under way? Don't the big ocean-racing cats use GPS to determine the speed at any given time?
