not annonymous wrote:
I would love to hear a decent explanation of why a concave bottom should flatten out at the tips.
Concave adds some stiffnes to the board and therefore progressive flex through the board. Not having concave to the end of the board, leaves the tip flexier.
If you make the concave too small, let's say just between the feet, it is going to produce vacuum under the board, therefore you will need a lot of strenght to get it out of the water when jumping. I guess it produces more drag too.