however, to a maximum elevation of 4.5° which reduced their range to less than . The existing wooden carriages for 11-inch guns were too long to fit in New Ironsidess cramped battery. A new iron carriage was built where the gun rode in a cradle that slid on iron rails. The new carriages pivoted at the gun ports to minimize the size of the ports. Two compressors, or clamps, were fitted to squeeze the rails and increase friction between the rails and the cradle, but these were not strong enough to handle the recoil force when the gun was fired. Two more compressors were fitted as well as rope breechings to restrain the guns, but neither was entirely satisfactory. The problem was not resolved until December 1862 when strips of ash wood were placed underneath the compressors; the friction of iron on wood was double that of iron on iron and the increased friction solved the problem. Armor New Ironsides had a complete waterline belt of wrought iron that was thick; below the waterline it was reduced to . It reached above the waterline and below. Above the belt the battery was protected by 4.5-inch armor, but the bow and stern were left unprotected. Although not initially part of the design, transverse bulkheads were added during construction to protect the ends of the battery. They consisted of of wrought iron backed by of white oak. The deck was three inches of yellow pine beneath of wrought iron. Mirroring French practice, the armor plates were secured to the ship's hull and deck by countersunk screws. The armor plates were cut with a groove on each side and an iron bar was inserted between each plate to better distribute the shock of impact. The side armor was backed by of wood. A conning tower with three-inch sides was also added during construction. It was placed behind the funnel and the mainmast, and had no visibility directly forward. It was small and could only fit three people. Each of the ship's gun ports was protected by two armored shutters, each thick. Each shutter rotated on an axle at its top operated from inside the battery. In combat these shutters frequently cracked or broke when hit; rarely was a shutter jammed in either the open or closed position. Construction and career New Ironsides was named in honor of , which earned the nickname "Old