I had a chunk out of the side of my pool when the landscapers finished (no one owned up to doing it). The pool company sent someone over and they repaired it underwater. I know it can be done - no draining Two other fiberglass pool owners I know have had repairs done underwater too, so don't let them tell you it can't be done. The man that was here used a long snorkle to go under and do the job. They have special stuff that cures underwater. I would call your pool company again.