i owned gps for a few years, fastest i got was around 30knots.this was on reach in chop. one day sailed in wake of fast ferry[no gps on] in 25knots of wind. got perfect run, felt minimun 5/10 faster than ever gone before.

if you can jag a strong gust in a millpond water state, many are capable, even lightweights of doing 40 knots.

doing 35 knots on a reach in chop,that to me is way harder.