WHY, you ask!
I have been a competitive water ski jumper for a number of years.
Can surf.
Been windsurfing almost at the top level since 1986.
Have some buds who are into the tow surfing thing.
All correlations seem to imply the average planing speed of a surfboard in “normal”, not Maalea Bay waves is around…15mph, going fast!
For a double glassed, 9’6" x 20" Wiamea designed gun to last more than 10 days windsurfing is IMPOSSIBLE! I broke TWO, one Steve Colleta, one Morgan Brewer. Both stressed fractured the bottoms, from in front of the fin to just in front of WP, multiple stress fractures starting 2nd day, first about 5" apart, then filling in rapidly.
Windsurfers travel around 26mph, in our area (SanFrancisco Bay). The pounding thru the chop, and such speeds, just tears up the surfboards.
And tow surfing practice at Cojo convinces me that normal funboards can’t handle much more than 13mph boardspeeds, and 6’8" x 18.5 semi guns maybe handle up to around 20 mph, then get sketchy, vibrating, oscillating, catching rails alternatively.
That’s towed behind a Avon with 40horse motor.
That’s why waterskis start to plane up at app. 23mph, notice they are narrow and thin!
But really, you are compromising your credibility with that statement.