RE: Why I'm into longboards
5 kn on the GO, I ment lightwind freestyle, like Ceasar on the Start,
You also learn a lot when sailing, learning going upwind on a shortboard in <8 kn.
As soon as you can plane on a (wide)shortboard, you are faster than a longboard, even on upwind/downwind course.
And considder, windrange for planing(most fun for most people in most conditions) :-) depends on rider weight.
So planing strarts from appr. 6-7 knots for leightweights and 8-10 knots for heawyweights