Awalkspoiled said..
Don't measure just at the tail - that'll be very imprecise. Instead, find the tuck-line of the board (the place where the rails transition into the undersurface) and run a piece of masking tape up along both sides for 1M or so such that the inner edge of the masking tape is right on that line. It'll be pretty easy on a board like the Supersport because that rail is pretty hard. Now take ten pieces of string and tape them down diagonally from one side of the taped tuck-lines to the other, starting on each side at equal distances from the tail (important) and criss-crossed in the middle. You'll now have a series of co-linear "X"s down the middle of the board. Trace that line back to the tail (another piece of tape) and that's a good approximation of center.
For a non-planing board like an old Superlight you'd use the outer edge of the board's curvature on each side rather than the tuck-line. Back in the '80s I used to do that pretty often for guys who wanted a more powerful fin than the old Mistral kick-back piece of plastic.
I think my t-square does the same thing a damn sight faster lol
It also shows that boards have too much variation to find a true centreline in most cases.
If it's straight relative to the rails in the back 1/3 of the board is about as good as u will get. If that means its pointing an inch off the nose, so be it.
And Gestalt I suggest it can be done with care. My board I'm building now has
zero rocker variation after 3 vac bag steps and using a a rocker spine/jig of course. (some have around 2mm extra rocker at tail which is easily rectified after laminating). Never had a board twist.
It should be 59.4 wide, and I leave a little bit of fat on the rail apex to allow for vac bag squishing. Its unfortunatley
59.6 wide, a grave injustice.
Now lets talk toe-in
