Balsa cored hulls - old boats
I have seen that go both ways. I have seen none cored hulls go aground and the flexure dislodge bulkheads and delaminate the hull at high load concentration areas and I have seen cored hull boats hit bottom at very high speeds (such as my Laser 28 which hit bottom surfing at nearly 9 knots) without discernable damage. It all comes down to engineering, build quality and luck in how the boat hit. Structurally, a properly engineered and constructed cored hull should be several times stonger than an equal weight non-cored hull. That is why coring is used in the first place.