The constructive consideration was the requirement of a protected armament capable of the maximum effective fire in all directions. In the first half of the century an increased effectiveness had been obtained, with the old-fashioned truck guns, by adaptation of the ports or by use of specially designed carriages, to permit of as large an arc of training as possible. Even so the arc through which guns could be fired was small, and in the case of the 68-pounder of the _Warrior_ was only thirty degrees before and abaft the beam. The demand for greater utility was emphasized when, with the increase in size of the unit gun, the number of pieces carried by each ship was diminished. How, then, having regard to these two considerations, should a warship’s guns be disposed? Various methods were adopted. In the first instance, it was seen to be possible to augment the ahead fire of a ship, and to give a wide sweep of training to some of her guns, by indenting the sides; by so shaping the ship’s side-plating as to allow guns mounted in the forward part to fire in the direction of the ship’s longitudinal axis. At first, slight use was made of this method: with the fine lines given to iron ships it appeared practicable in only a small degree. Moreover, it was objected to as causing a “funnelling” effect to the path of fragments of enemy shell or shot; it was found that shrapnel shell, fired at indented embrasures at Shoebury, broke up, and the number of balls which entered the portholes was ten times the number which entered similar portholes on a straight side. But, after the _Minotaur_ class, less length and greater beam were given to ships, and recessed ports and indented sides therefore became more feasible. As guns increased in weight and individual importance the advantages of concentration became apparent. It was now undoubtedly desirable to protect _all_ the guns; yet, if they had been strung out along the whole length of the ship, the weight, both of the guns and their protective armour, would prove to be an excessive burden to the ship. Hence the advantage of the _central battery_. By concentrating the guns into a central area, an armoured box amidships, the weight of armour necessary to protect them could be kept within reasonable limits, protection was afforded not only to the guns but to the vital parts of the ship, while at the same time the extremities were left lightly loaded. The complete water-line belt of armour was retained, but, both in the French and in the English navy, the system of complete protection as embodied in the _Gloire_ and _Warrior_ was given up.