Problem: The ark was only made of wood and carried a heavy load of cargo. But, a world-wide flood produces violent waters that would have broken it in pieces (cf. Gen. 7:4, 11).
Solution: First, the ark was made of a strong and flexible material (gopherwood) that “gives” without breaking. Second, the heavy load was an advantage that gave the ark stability. Third, naval architects inform us that a long box-shaped, floating box-car, such as the ark was, is a very stable craft in turbulent waters. Indeed, modern ocean liners follow the same basic dimensions or proportions of Noah’s ark.