If you are trying to make a long curved section, laminate up from thinner sections using epoxy just like building a stitch and tape hull.
If you are trying to obtain a curved edge to follow the hull as in a bulkhead get some large cardboard or foam core and "scribe" with an extended pencil compass to give you a cut line. The pattern should be vertical, measure the distance from far edge to hull and add to your final pattern.
Bill Uffelman
Las Vegas NV