defined Battlecruiser on Ivory-Tower: Battlecruisers shared the very large main armament of battleships, and were generally as large and costly as battleships of the same generation. They traded off armour or firepower for higher speed, which was made possible by their powerful engines and slender hulls. The earliest battlecruisers carried significantly less armour than the equivalent battleship, meaning they were not intended to stand up against the guns they themselves carried. Thus ships of this type could inflict much more punishment than they could endure.