Sounds like an odd topic, but it would be interesting to see just how fast an 8.5 sail can go!
80 kg / Hyper 111 / 8.4 RS6 / 41cm RS Viper
Wind 12 - 16-18 / 30 cm chop
2 Sec / 28.44 knots
I am picking with nice flat water and consistant wind, perhaps 30 knots would be about it.