I did have problems with my hull flexing where the keel and the bow meet, it got so bad that it developed a huge crack. What I did was cut out a piece of the glass there and fabricate a metal brace to tie the two pieces together, then used epoxy putty around it and glassed it over. That was about 12 years ago and the hull is much stronger because of it and I have never had any flexing since then or any problems.