This is a complicated question and admittedly I know just enough about it to be dangerous...but here's my take...volume up front prevents pitch polling and helps keeps the bow up increasing the speed potential and decreasing the sensitivity to wave height. Volume in the center will help with tacking ease allowing the boat a fat middle point to pivot on. Volume in the rear helps the boat plane downwind. Rocker and daggerboard position affect tacking and upwind efficiency. More volume / flatter sections affect drag. Hull shape is a balance of all of these variables.