When I cut the hub from an unplaned four-by-one inch (100x25mm) plank that was hanging around the workshop, I truncated the tip of the triangle by a fraction so as to leave a void between the foremost parts of each spar, into which I've dropped a dowel (with thanks to our sponsor, IKEA) by way of a snubber to hold the ski in situ whilst a two-inch screw is driven into the block. By altering this position along with the extent to which the screw is driven, the curvature of the ski can be adjusted.
In fact by altering the angle between the sides of the hub you'll do much the same with the curvature of the laterals; for the simplest however the curvatures here are broadly representative of their flexure when simply brought to the same point.
What I do as a belt-and-braces means of securing this front end is simply to squirt a dose of adhesive into the void... those that foam slightly are ideal for doing this. By these means the attachment is prevented from working loose so that we can avoid that dreaded 'Hydroski Fire, Severe Damage or Separation' drill' when in operation.
