Hi Ola!
As a windsurfer with some mathematics and programming background, I stumbled upon your interview on windsurfing.tv (https://www.youtube.com/watch?v=EtLAJT1pNgA) and this peeked my interest. Super interesting !! I read some basics about NURBS as a hobby, because I like to understand things - and maybe who knows, shape a windsurf board for fun some day 
I have a question about your process:
Let’s imagine we are designing an ouline. In the standard parameterization Q(t) of a NURB (with order, control points, knots, and possibly weights), we obtain cartesian coordinates x,y as a function of t on an interval. We can then obtain curvature at any t. But in your windsurfing.tv interview, it seems that you use a different parameterisation of NURBS: you specify curvature for a set of x on the central line of the board (if I understand well?) and I imagine that your program translates this into the standard NURBS parameters. Are you able to explain, or do you have a good reference, about how to do this reparameterization ?
Thanks!
Arnaud
