jrd22, You have a lot more faith in the Gov't than I. A whole lot more.
bubb and dog, Everything flexes and it must be allowed for in your design. In a boat you may also have to deal with inspectors and insurance companies. However this is as much a political problem as an engineering one. Even in houses I have run across broken fittings and pipes simply because there was not sufficient room to allow them to move when necessary. For instance when a pipe goes from hot to cold over time it must move. If it can't something will break.
I would never join a hull to a cockpit with anything rigid. It will break sometime.
Seafarer 29 KCB