Check the Magellan line of GPS's. They have a few that are 100% waterproof. I have Garmin eTrex Legend and it is a fantastic GPS and has all sorts of things on it. (square acreage (area) calculators, fish/hunt calendars, etc...etc... Plus it can upload/download maps. My eTrex Legend is "sort of" waterproof - to an extend. It will survive for a few moments if dropped in the water, but can't bedropped like into a 15' deep pond.