If you need to get the cap off, there are several ways of supporting the hull so she don't get all floppy. Guys have used 2x2's cut to fit exactly between the gunnels at regular intervals, and screwed from the outside, some guys have used threaded rod with washers and nuts, I built a cradle to support the outside, and some have used ratchet straps wrapped around the hull to keep it from flexing outward. The point is to get your braces in place BEFORE you remove the cap, that way you will eliminate any guess work from the shape of the hull. Also, don't forget to make sure the bottom of the hull is supported as well, because it will start to flex as you remove the deck and stringers. There is my two cents worth!