This won't work for hulls but foils?....
Strojnick... suggests this technique that is sometimes used for making airplane wings. Lay up a skin of fiberglass on a piece of Plexiglas. When it has partially set, but not yet hard, peel it off the plastic and form it around a male mold for the final cure. This gives a very smooth finish without the difficulty of having to make your mold very smooth. His books go into much more detail.