ship were replaced by eight new Kampon oil-fired boilers, fitted into the former aft boiler room, and the forward funnel was removed. The turbines were replaced by four geared Kampon turbines with a designed output of intended to increase their speed to . On her trials, Ise reached a top speed of from . The fuel storage of the ships was increased to a total of of fuel oil that gave them a range of at a speed of . Armament The twelve 45-calibre Type 41 guns of the Ise class were mounted in three pairs of twin-gun, superfiring turrets. Numbered one through six from front to rear, each turret weighed . The hydraulically powered turrets had an elevation capability of −5/+20 degrees. The guns had a rate of fire of 1.5–2 rounds per minute and could be loaded at any angle between −3 and +20 degrees. In 1921 the elevation was increased to +30 degrees and then to +43 degrees during their mid-1930s modernization, except for No. 6 turret as its supporting structure could not be lowered. The recoil mechanism of the guns was also changed from a hydraulic to a pneumatic system, which allowed for a faster firing cycle of the main guns. By World War II, the guns used Type 91 armour-piercing, capped shells. Each of these shells weighed and was fired at a muzzle velocity of . They had a maximum range of at +20 degrees of elevation and at +43 degrees after modernization. Also available was a high-explosive shell that had a muzzle velocity of . A special Type 3 Sanshikidan incendiary shrapnel shell was developed in the 1930s for anti-aircraft use. The ships' secondary armament consisted of twenty 50-calibre Type 3 guns. Eighteen of these were mounted in casemates in the forecastle and superstructure and the remaining pair were mounted on the deck above them and protected by gun shields. They had a maximum elevation of +20 degrees which gave them a range of . Each gun had a rate of fire of up to 10 rounds per minute. Anti-aircraft defence was provided by four 40-calibre 3rd Year Type 8-centimetre AA guns in single mounts. The high-angle guns had a maximum elevation of +75 degrees, and had a rate of fire of 13 to 20 rounds per minute. They fired a projectile with a muzzle velocity of to a maximum height of . The