Many have called the swept back X bows or America’s Cup Bows simply a fashion. I say they have real advantages. The argument against says that you lose buoyancy as the hull buries. That is true, but you also lose drag. It becomes more wave piercer. And at the moment you lose a few hundred pounds of displacement, you are actively participating in hundreds of thousands of foot pounds of a verb. A few hundred pounds are irrelevant. Now check this out. A link sent to me by Owen Myers. The military often has a big enough budget to research things. See http://www.militaryphotos.net/forums/showthread.php?152989-Xbow-Sea-Axe-A-future-in-the-Military-Design