carried twenty-four 25 mm Type 96 anti-aircraft guns, primarily mounted amidships. In 1944, both Yamato and Musashi underwent significant anti-aircraft upgrades in preparation for operations in Leyte Gulf using the space freed up by the removal of both midships secondary battery turrets, and ended up with a complement of twenty-four guns, and one hundred and sixty-two antiaircraft guns, The 25 mm anti-aircraft guns could tilt at 90-degree angles to aim at planes directly overhead, but their mountings' lack of protection made their gunnery crews extremely vulnerable to direct enemy fire. These guns had an effective range of , and an effective ceiling of at an elevation of +85 degrees. The maximum effective rate of fire was only between 110 and 120 rounds per minute because of the frequent need to change the fifteen-round magazines. This was the standard Japanese light AA gun during World War II; it suffered from severe design shortcomings that rendered it a largely ineffective weapon. According to historian Mark Stille, the twin and triple mounts "lacked sufficient speed in train or elevation; the gun sights were unable to handle fast targets; the gun exhibited excessive vibration; the magazine was too small, and ... the gun produced excessive muzzle blast". The class was also provided with two twin mounts for the licence-built 13.2 mm Type 93 anti-aircraft machine guns, one on each side of the bridge. The maximum range of these guns was , but the effective range against aircraft was only . The cyclic rate was adjustable between 425 and 475 rounds per minute; the need to change 30-round magazines reduced the effective rate to 250 rounds per minute. The armament on Shinano was quite different from that of her sister vessels due to her conversion. As the carrier was designed for a support role, significant anti-aircraft weaponry was installed on the vessel: sixteen guns, one hundred forty-five anti-aircraft guns, and three hundred and thirty-six anti-aircraft rocket launchers in twelve twenty-eight barrel turrets. None of these guns were ever used against an enemy vessel or aircraft. Armor Designed to engage multiple enemy battleships simultaneously, the Yamatos were fitted with heavy armor plating described by naval historian Mark Stille as providing "an unparalleled degree of protection in surface combat". The main belt of armor along the side of the vessel was up to thick, with transverse bulkheads of the armoured citadel up to thick. A lower belt