The Mackensens were equipped with a main battery of eight ne

The Mackensens were equipped with a main battery of eight new 35 cm SK L/45 guns[b] in four twin gun turrets. The turrets were mounted in superfiring pairs fore and aft of the main superstructure. The guns were placed in Drh LC/1914 mountings,[11] which could elevate to 20 degrees and depress to −5 degrees. The guns were supplied with a total of 720 armor-piercing shells, or 90 per gun. The weapons were designed to fire 600 kg (1,323 lb) shells at a rate of fire of around 2.5 shots per minute. The shells were fired with a muzzle velocity of 820 meters per second (2,700 ft/s). As with other heavy German guns, these weapons used a fore propellant charge in a silk bag with a main charge in a brass case. These guns could hit targets out to a maximum distance of 23,300 m (25,500 yd).[12][13]

The ships' secondary battery consisted of fourteen 15 cm (5.9 in) SK L/45 quick-firing guns mounted in armored casemates along the central superstructure. Each gun was supplied with 160 rounds, and had a maximum range of 13,500 m (44,300 ft), though this was later extended to 16,800 m (55,100 ft). The guns had a sustained rate of fire of 7 rounds per minute. The shells were 45.3 kg (99.8 lb), and were loaded with a 13.7 kg (31.2 lb) RPC/12 propellant charge in a brass cartridge. The guns fired at a muzzle velocity of 835 meters per second (2,740 ft/s). The guns were expected to fire around 1,400 shells before they needed to be replaced.[14][15]

The ships were also armed with eight 8.8 cm (3.45 in) L/45 Flak guns in single pedestal mounts. Four were arranged around the rear superfiring main battery turret and the other four around the forward conning tower. The Flak guns were emplaced in MPL C/13 mountings, which allowed depression to −10 degrees and elevation to 70 degrees. These guns fired 9 kg (19.8 lb) shells, and had an effective ceiling of 9,150 m (30,020 ft) at 70 degrees.[16][15]

As was standard for warships of the period, the Mackensens were equipped with submerged torpedo tubes. There were five 60 cm (24 in) tubes: one in the bow, and two on each flank of the ship. The torpedoes were the H8 type, which were 9 m (30 ft) long and carried a 210 kg (463 lb) Hexanite warhead. The torpedoes had a range of 8,000 m (8,700 yd) when set at a speed of 35 knots (65 km/h; 40 mph); at a reduced speed of 28 knots (52 km/h; 32 mph), the range increased significantly to 15,000 m (16,000 yd)