In the very beginning of this blog Finlenght vs Speed was written, now it is time to look again. We have to think everything around the finlenght was optimized for best speed... These are not mine speeds (I wish), but best performances from all around the world. The speed given is 5x fastest 10sec average, measured with GPS, data found in gps-speedsurfing.com database.

20cm__46,3kn
25cm__44,2kn
30cm__42,3kn
35cm__39,0kn
40cm__36,0kn
45cm__34,0kn
50cm__32,0kn
55cm__28,3kn
60cm__31,0kn

Interesting fact is that thin foils, thick twisty foils, powerfull fins, non twist or any other design seems to have almost the same speed vs lenght. Most seen is the tectonics falcon f1 in the lenght list.

A linear formula which suits a bit in finrange 20cm-55cm:

Speed [knots] = -0,45*Finlenght[cm] + 55

You should pick the right finsize for the speed you are aiming at, now this finlenght formula could become handy. SO far I used 1-3cm shorter than this formula, I bet <70kg speedsurfers can do up to 5cm shorter. Most high speed on maximum finlenght is done by heavier guys. So for lighter windsurfers I guess the formula should be changed a bit.

It is a guideline, nothing more ;)