Hull Flex ?

[BigMike8o9]

My boat was over flexing. Because of some damage before I bought my walkaround. I checked the bulkhead and found it crushed and rotted.
My experience has showed that even exceleration can flex a boat. I beefed up and replaced the bulkhead. Also filled in most of the screw holes for the screws that hold the deck to the hull and made the sides of the deck thicker by grinding out some of the core and making the glass several layers thicker. I know I have way to much free time. But when the deck screws went back in tight the boat became very stiff with only a very minamal flex. Even the transom is much stiffer.
The bulkhead helps keep the boat from flexing outwards because I glassed and screwed it tight at the gunnels and the space between the bottom of the hull and deck are supported by the stronger bulkhead. if it is supported the boat cant flex out ward because the cabin and deck would need to compress for this to happen. The movement caused the srews to become loose and worked the holes so that the screws could not be made tight. I also put fibrglass tape behind the srew holes after filling them. to strenthen the hold. I can tighten them almost to brake if I try to hard.