Matt is right. This is an argument I normally avoid. Composites have a limited life. Polyester foam core, like yours is one of the shorter ones. There is no easy way to reinforce or repair your hull. I would guess that age and use are starting to make your hull flexible at a minimum or more likely, starting to delaminate.


As for crew weight, we were given an upper limit of 450 lbs when we were racing 18 magnums and those boats were new