Collision of factors?? YES, Unavoidable.. not really. And the captain of the boat "sunk" the boat, not the fish. Backing down hard on an acrobatic Bill Fish is not uncommon, take one or two big waves over the stern, everyone heading to the same corner of the cockpit, Bilge pump is overwhelmed, once that gunwale drops low enough to start taking water over the side, it's pretty much over..