Hi Aaron, might have been better to post in Windsurfing, GPS Speedsailing

The Navi is the best so just grap one of those, it's what most of us use, then ask Q's on the dark side if you need help.
Make sure you get a waterproof bag, don't trust any GPS without one, this is the one I use
www.whitworths.com.au/ works fine
Cheers Bob.
Edit, Bloody hell Nebs do you use more than two fingers to type