Type 3") anti-aircraft shells. A time fuze was used to set how far away the shells would explode (although they were commonly set to go off away). Upon detonation, each of these shells would release 900 incendiary-filled tubes in a 20° cone facing towards incoming aircraft; a bursting charge was then used to explode the shell itself to create more steel splinters, finally, the tubes would ignite. The tubes would burn for five seconds at about and would start a flame that was around long. Even though they comprised 40% of the total main ammunition load by 1944, 3 Shiki tsûjôdan were rarely used in combat against enemy aircraft due to the severe damage the firing of these shells inflicted on the barrels of the main guns; indeed, one of the shells may have exploded early and disabled one of Musashis guns during the Battle of the Sibuyan Sea. The shells were intended to put up a barrage of flame that any aircraft attempting to attack would have to navigate through. However, U.S. pilots considered these shells to be more of a pyrotechnics display than a competent anti-aircraft weapon. Secondary armament In the original design, the Yamato class' secondary armament comprised twelve 15.5 cm/60 Type 3 guns mounted in four 3-gun turrets (one forward, two amidships, one aft), and twelve 12.7 cm/40 Type 89 guns in six double turrets (three on each side amidships). These had become available once the Mogami-class cruisers were rearmed with guns. With a AP shell, the guns had a maximum range of at an elevation of 45 degrees. Their rate of fire was five rounds per minute. The two midships turrets were removed in 1944 in favor of additional heavy and light anti-aircraft guns. Initially, heavy anti-aircraft defence was provided by a dozen 40-caliber 127-mm Type 89 dual-purpose guns in six double turrets, three on each side of the superstructure. In 1944, the two amidship 15.5 cm turrets were removed to make room for three additional 127-mm mounts on each side of Yamato, bringing the total number of these guns to twenty-four . When firing at surface targets, the guns had a range of ; they had a maximum ceiling of at their maximum elevation of 90 degrees. Their maximum rate of fire was 14 rounds a minute; their sustained rate of fire was around eight rounds per minute. Anti-aircraft armament The Yamato class originally