in the same casing, driving an inner shaft. Her three-bladed propellers were in diameter. The turbines were powered by 39 Babcock & Wilcox water-tube boilers in five boiler rooms at a working pressure of . The turbines were designed to produce a total of and a maximum of when forced, but only achieved during her sea trials, although she managed to exceed her maximum designed speed of by over a knot. The ship's fuel stowage capacity was of fuel oil and of coal, giving a total fuel supply of —much more than Queen Marys total of . The sole (unofficial) figure for Tigers daily fuel consumption of a day at would have given a maximum endurance of . The equivalent figure for Queen Mary was roughly . Four direct current electric dynamos with a total capacity of supplied the common ring main at 220 volts. Armament Tiger mounted eight 45-calibre BL 13.5-inch Mk V guns in four twin hydraulically powered turrets, designated 'A', 'B', 'Q' and 'X' from front to rear. The guns could be depressed to −5° and elevated to +20°, although the directors controlling the turrets were limited to 15° 21' until superelevating prisms were installed before the Battle of Jutland in May 1916 to allow full elevation. They fired projectiles at a muzzle velocity of ; at 20° elevation, this provided a maximum range of . The rate of fire of these guns was approximately 2 rounds per minute. The ship carried a total of 1040 rounds during wartime for 130 shells per gun. Her secondary armament consisted of twelve BL 6-inch Mk VII guns in casemates. The guns could depress to −7° and had a maximum elevation of 14°. They fired projectiles at a muzzle velocity of approximately ; this gave a maximum range of at +14° elevation. They were provided with 120 rounds per gun. The ship mounted a pair of QF 3 inch 20 cwt Mk I anti-aircraft guns on high-angle Mark II mounts. The gun had a maximum elevation of +90° and fired a shell at a muzzle velocity of . It had a maximum effective ceiling of . Originally, Tiger carried 300 rounds per gun, but this was reduced during the war to 150 rounds per gun. Four submerged torpedo tubes were fitted on the beam, one pair port and starboard forward of 'A' barbette and aft of 'X' barbette. The ship