Just a quick heads up. Another watch is out for gps speed sailing, approved by gp3s.com. Gp3s.com helped write the software. It's not cheap but looks good, could be used for other stuff too. I am no gps expert so I don't know about all the tech stuff. I think there are two Coros watches available, the apex pro and the
shop.gps-speedsurfing.com/coros-apex-pro and vertex.