SMS Von der Tann was the first battlecruiser built for the German Kaiserliche Marine, as well as Germany's first major turbine-powered warship. At the time of her construction, Von der Tann was the fastest dreadnought-type warship afloat, capable of reaching speeds in excess of 27 knots. She was designed in response to the British Invincible class. While the German design had slightly lighter guns—28 cm (11 in), compared to the 30.5 cm (12 in) Mark X mounted on the British ships—Von der Tann was faster and significantly better-armored. She set the precedent of German battlecruisers carrying much heavier armor than their British equivalents, albeit at the cost of smaller guns.
Von der Tann before the war
Von der Tann as depicted in Brassey's Naval Annual in 1913; shaded areas represent armor protection.
Von der Tann in 1911
SMS Mainz sinking, with the British destroyer HMS Lurcher alongside, picking up survivors
The battlecruiser was a type of capital ship of the first half of the 20th century. These were similar in displacement, armament and cost to battleships, but differed in form and balance of attributes. Battlecruisers typically had thinner armour and a somewhat lighter main gun battery than contemporary battleships, installed on a longer hull with much higher engine power in order to attain greater speeds. The first battlecruisers were designed in the United Kingdom, as a development of the armoured cruiser, at the same time as the dreadnought succeeded the pre-dreadnought battleship. The goal of the design was to outrun any ship with similar armament, and chase down any ship with lesser armament; they were intended to hunt down slower, older armoured cruisers and destroy them with heavy gunfire while avoiding combat with the more powerful but slower battleships. However, as more and more battlecruisers were built, they were increasingly used alongside the better-protected battleships.
HMS Hood, the largest battlecruiser ever built, in Australia on 17 March 1924
HMS Shannon, a Minotaur-class armoured cruiser
Invincible, Britain's first battlecruiser
HMS Queen Mary, the last battlecruiser built before World War I