Re: Below Deck
I think you would need a marine engineer to tell you why a vessel sank. I'm a sailor but I can't tell you what side loading is required to blow a vessel over, or the speed at which water would enter a specific compartment inside the hull, or how that hull might behave when hit by a tornado.
On one aspect - smaller boats can bob around like corks, whereas large vessels are subjected to much greater internal forces, to the extent where tankers and bulk carriers have been known to snap in half when subjected to the "wrong" wave length (for that vessel).