water-tube boilers and they now had a maximum speed of . The boilers exhausted through a single downturned starboard funnel and the ships carried of fuel oil, giving them a range of at a speed of . Their crew numbered 785 officers and men. Their flight deck was long and had a maximum width of . The ships were designed with a single hangar long and wide. The hangar was served by two octagonal centerline aircraft elevators. The forward elevator was 13 by 12 meters (42 ft 8 in × 39 ft 4 in) in size and the smaller rear elevator measured 12 by 10.8 meters (39 ft 4 in × 35 ft 5 in). The ships had arresting gear with six cables, but they were not fitted with an aircraft catapult. The Zuihō-class carriers were a flush-deck design and lacked an island superstructure. They were designed to operate 30 aircraft. The primary armament consisted of eight 40-caliber 12.7 cm Type 89 anti-aircraft (AA) guns in twin mounts on sponsons along the sides of the hull. They fired projectiles at a rate between 8 and 14 rounds per minute at a muzzle velocity of ; at 45°, this provided a maximum range of , and a maximum ceiling of . The ships were also initially equipped with four twin 25 mm Type 96 light AA guns, also in sponsons along the sides of the hull. They fired projectiles at a muzzle velocity of ; at 50°, this provided a maximum range of , and an effective ceiling of . The maximum effective rate of fire was only between 110 and 120 rounds per minute due to the frequent need to change the fifteen-round magazines. In 1943, Zuihōs light AA armament was increased to 48 twenty-five mm guns. The following year, an additional twenty 25 mm guns were added in addition to six 28-round AA rocket launchers. Each rocket weighed and had a maximum velocity of . Their maximum range was . Ships Service After commissioning, Zuihō remained in Japanese waters until late 1941, becoming the flagship of the Third Carrier Division on 30 September. Together with the carrier and eight battleships, Zuihō covered the return of the ships of the 1st Air Fleet as they returned from the attack on Pearl Harbor in mid-December. Aside from one trip to transport aircraft to the Philippines, she remained in Japanese waters until