Cannons fired bags of nails, to maim people but leave ships intact
                                
                                
                                    (Newser) -
                                    Blackbeard's ship, Queen Anne's Revenge, now being explored by marine archeologists off the coast of North Carolina, is giving up more than just its  treasures , it's also revealing the infamous pirate's terrifying tactics. And what researchers are finding are an ingenious array of improvised weapons, designed...