To date, the fastest I've recorded on a beach at was on a 1978 solcat 18 at 24.4 mph in +30 mph of wind.
Since then I've sailed a N.5.0, N5.7, N6.0, NI20- all but the 5.0 running chutes. The fastest speed I've recorded is 23.6. So I'm more than a little pissed!
A buddy of mine and his crew collectively weighed +450 and ran a N5.8 with a hooter, double trapped, at 28.6 for an extended period, ie 10 seconds, and pitchpoled. I watched them from my 6.0 running parallel, at +_20 and they left me standing still. I'm not sure of their real speed, but it believe it was close to the GPS.
I'm still gunning for the 24.4 clocked on the SolCat dammit! Correct GPS or not!
Did get caught in a squall in Mexico, and had to be running DDW AT OVER 60MPH, with crew trying to pull daggers so I could beach, but I could be way off!!