Having spent time making a straight box beam and good stations, I find that the end forms (cut from 1/2" BC plywood) has curves in them. Any suggestions? Do I need to recut these out of 1/2" MDF, or is there a way to straighten them. Am building the Night Herron and don't have much room on either side to laminate a stiffner 90 degrees (parallel to the water line,perpendicular to the centerline).

Any suggestions greatly appreciated.