Once you glass the inside of the hull and it hardens to the touch, you should re-insert some forms and use some web straps to tighten it up to the forms. A few forms in the wide area will do it. It's easier to fix one that goes wider than closes up. Now is the time to act and do this. You can buy straps with a cam ratchet tightening mechanism or just get a helper to pull it into the forms and use straps to bring it in to the form width. The epoxy is quite flexible for many days once it sets up. Let it sit like that for a few days. Do the same with a few deck forms too. Normally decks since they a flatter don't distort as much as the hulls.

Don't panic, just act now on it. Absolute worse case scenario, you would put a few cross beams in and screw into them and attach the deck and hull. Later you would remove them and fill the screw holes. When a hull closes up you would do the same thing.