of coal and oil. The ship had a stowage capacity of of coal and of fuel oil, giving her a range of at a speed of . The ship exceeded her designed speed of during her sea trials, reaching at . During a refit in 1924 the fore funnel was rebuilt in a serpentine shape in an unsuccessful effort to prevent smoke interference with the bridge and fire-control systems. That funnel was eliminated during the ship's 1930s reconstruction when all of her existing boilers were replaced by ten lighter and more powerful oil-fired Kampon boilers, which had working pressures of and temperatures of . In addition her turbines were replaced by lighter, more modern, units. When Mutsu conducted her post-reconstruction trials, she reached a speed of with . Additional fuel oil was stored in the bottoms of the newly added torpedo bulges, which increased her capacity to and thus her range to at 16 knots. Armament Mutsus eight 45-caliber guns were mounted in two pairs of twin-gun, superfiring turrets fore and aft. Numbered one to four from front to rear, the hydraulically powered turrets gave the guns an elevation range of −2 to +35 degrees. The rate of fire for the guns was around two rounds per minute. A special Type 3 Sankaidan incendiary shrapnel shell was developed in the 1930s for anti-aircraft use. The turrets aboard the Nagato-class ships were replaced in the mid-1930s using those stored from the unfinished s. While in storage the turrets were modified to increase their range of elevation to −3 degrees to +43 degrees, which increased the guns' maximum range from . The ship's secondary armament of twenty 50-calibre guns was mounted in casemates on the upper sides of the hull and in the superstructure. The manually operated guns had a maximum range of and fired at a rate of six to ten rounds per minute. Anti-aircraft defence was provided by four 40-calibre 8-centimetre (3 in) 3rd Year Type AA guns in single mounts. These guns had a maximum elevation of +75 degrees, and a rate of fire of 13 to 20 rounds per minute. The ship was also fitted with eight torpedo tubes, four on each broadside, two above water and two submerged. Around 1926, the four above-water torpedo tubes were removed and the ship received three additional 76 mm AA guns that were situated around the base of the foremast. The