In that case I would heat it and bend it back and fix it in that position. You could cut out frames in the shape the top should be, hot glue it to them and then put another skin of fibreglass on the bottom. That might hold it.
JohnK

: I forgot to state that I did fiberglass both sides. I fiberglassed the
: outside when I did the entire deck and then I did the bottom when I cut
: out the hatch lid. I think it warped when I did the bottom and need to
: know how to force it back.

: Charles Robinson