An alternative would be to carve the entire hull from light density styrofoam, paint a release agent on it, cover in fine cloth fibreglass and resin and once cured, remove the styrofoam, or at least, remove as much as you need to.
i have used this to make a decent sized hull and it works ok. The initial cover can be roughly sanded with wet and dry paper, then p38 or similar car body filler laid on, which will enable a smooth surface to be obtained.
The initial block would be two halves, top and bottom, enabling you to cut through to separate once the hull is to shape. Also, by making the initial large blocks from multiple small blocks, with only the outer ones glued together, enables easy removal of these blocks afterwards, and a lot of the foam could be left in situ to add strength.
Something else to think about would be to vac form the hull. A denser foam is used, and a thin plastic is formed over it, two halves..top and bottom. Remove again as much styrofoam as needed, but leave enough to support the thin outer plastic. You would have to use a thin plastic outer or the former would need to be quite substantial, wood or plaster.
Ashley
Edited By ashley needham on 18/02/2023 10:02:48