Here is a view of the Bottom showing a 3/8" deep concave that starts about 12" from the nose end and runs throughout the planshape to the tail. Since the board has a convex shape on the deck, its net thickness is really averaging about 1/2 to 5/8" thick. This makes it flex under compression in turns, and a strong snap back to shape, giving you a surprising thrust out of the turn.
Sunset Magazine, July 1927, with modern bathing beauty riding an Alaia surfboard in Waikiki. 407-222-9944
Greg
