perhaps half the functionality of the etrex, or any gps really, comes from just what's on the screen while you are using it. instantaneous speeds, max speed etc. don't forget to try and save your race buoys as waypoints and create a route that goes from each one to the end. then you can set the display to large, and select, speed, max speed and VMG, to experiment with sailing angles

another huge area of functionality comes when you download the track data to a computer. mapsource is garmin's gps program but as garmin are the defacto standard of small gps there are also many freeware programs out there

GPS action replay is my current fav.

http://www.youtube.com/watch?v=BNAsxV1ltMU

with the HCX etrex series you get H high sensitivity, C color screen to make reading map detail much faster and X expandable memory. the memory also stores track data so you can put in a cheap 2GB microSD card, set track data record points to "most often" and then get very detailed plots