There is a forum here called "GPS and speed talk", but it is more oriented for speed, I'm not sure about wave analysis. but looking at you google earth tracks should show how many waves you've caught.
You Could try GPSvisualizer, you can colour code your tracks for speed, that would give some indication. And you'd be able to see wave tracks.
Here's one I've just done to test how GE is working.
So G.E. have changed things a bit, you used to be able to get the speed legend in the image panel, but now I can only get it off to the side.
Or there's,
www.ka72.com/There's many different categories there, not just speed sailing.