John ---- all depends on the lay-up sequence and timing.
There can be major problems with cored hulls that arise in the lay-up techniques at the boat yard. Cored hulls are stronger and lighter weight BUT such hulls must be continually layed-up in ONE single step or there will eventually be problems. Polyester, etc. resin once its partly cured doesnt have the bond strength to the next successive lay-up as when one layer is quickly added on top of one another as in a 'continuous process'. Todays 'top drawer' boats are made in one step (the workers dont knock off at 5PM and come back early in the next morning and begin again where they left off yesterday). If the lay up is discontinuous then the bond strength between the laminate schedules will be weak; doesnt matter if the hull is solid or cored. Only the 'high end' boats will do a continuous process .... the 'others' havent seemed to have 'caught on' yet. So, a cored boat which takes more time to construct has more potential of individual lay-up layer delamination ... if it wasnt layed up in a single continuous process. Thermal stress is a big deal with cored hulls, especially if the hull is a dark color. The example is Niagara which most surveyors will attest that they usually find delaminations in a dark hulled Niagara - simply because the dark hulls get too hot from the sun. Impact is big too-doo with a cored hull, especially if the bond strength between the successive layers due to discontinuous lay-up is poor, especially if the core is now crushed from the impact. Any cored hull that shows evidence of impact .... to me, makes this a 'walk away from boat'. .... and all this is 'besides' the water absorption issues. A good cored hull is lighter, stronger and longer lasting than a solid hull; but, there are traps that one should be aware of.
