...from the Monitors. He had seen in the fight of the Monitor and Merrimac that 11-inch shot would not penetrate the 4-inch armor of the latter, and he had seen, from the reports of the bombardment of Fort Sumter by the Monitors, that 15-inch shot had not enough penetrating power to break through masonry that was easily bored through and through by a 6-inch rifle. He knew that the fleet had very few rifled ...