I had a similar problem,caused by having to wait 2 weeks between glassing the inside and outside of the deck .I had to make up 3 large C clamps,big enuf to fit across the boat,and used glass tape and epoxy> to glue a small segment together,then to procede to the next areaa foot or so down the seam.It ended up OK,but I was V unhappy for a while.My gap was 1 3/4 inches in width,and 1 1/4 in height.Beware- you stress the deck ,and I had to make new hatch covers to match the new curve. Dont despair ,it will turn out , Progress has been good so far but I have hit a problem jointing the hull
> to the deck. The hull has closed in a about 10mm and I am having all sorts
> of trouble getting the tape to hold the hull in place. Could I glue the
> seam or what, this is so frustrating. Phill