Passage: The ship was 167.2 m (548 ft 7 in) long overall, had a beam of 28.5 m (93 ft 6 in) and a draft of 8.94 m (29 ft 4 in), and displaced 24,700 metric tons (24,310 long tons) at full load. She was powered by three vertical triple expansion steam engines and fifteen water-tube boilers. The engines were rated at 27,617 ihp (20,594 kW) and were capable of producing a top speed of 21 knots (39 km/h; 24 mph). Thüringen stored up to 3,200 metric tons (3,100 long tons) of coal, which allowed her to steam for 5,500 nautical miles (10,200 km; 6,300 mi) at a speed of 10 knots (19 km/h; 12 mph). After 1915, the boilers were modified to spray oil on the coal to increase its burn rate; the ship could carry up to 197 metric tons (194 long tons) of fuel oil. She had a crew of 42 officers and 1,071 enlisted men.Thüringen was armed with a main battery of twelve 30.5 cm (12.0 in) SK L/50 guns in six twin gun turrets, with one turret fore, one aft, and two on each flank of the ship. The ship's secondary armament consisted of fourteen 15 cm (5.9 in) SK L/45 guns and fourteen 8.8 cm (3.5 in) SK L/45 guns. After 1914, two of the 8.8 cm guns were removed and replaced by 8.8 cm anti-aircraft guns. Thüringen was also armed with six 50 cm (20 in) submerged torpedo tubes; one was in the bow, one in the stern, and two on each broadside.

Question: What was thuringen's max speed?
10 knots