I think Matt (WorlSUP) got it right, especially since he was wearing a GPS = 4.65km. That's an average of 7.54km/h for my race which seems about right. And yes the turning buoy did move during the race.
Here are some pics from Dez from Blast Paddlers (more on their Facebook page). They don't do the size of the mountains of water out the back justice:
Start line caos:
Andy Davies (DC14) - 1st and now $500 richer thanks to WindSurfnSnow:
Pete Meyer (Naish 17) - 2nd:
Finding a break in the shorey without loosing a place:
Close:
Careful:
Board caddys doing a great job: