For onboard point of view shots like Greenough got I’m using the GoPro HD Hero(the cam in the picture is the older GoPro Surf Hero).

I’ll also(mostly) use a helmet cam setup like below:

I really don’t see how Greenough did it with 20+ lbs. of camera gear on his back. My respect for the man grows daily.

photo by Harold Ward from georgegreenough.com

Frame grab from older GoPro Surf Hero: