Prinz Adalbert-class cruiser

SMS Prinz Adalbert
Class overview
Name	Prinz Adalbert
Operators	Imperial German Navy
Preceded by	SMS Prinz Heinrich
Succeeded by	Roon class
Built	1900–1904
In service	1903–1916
Completed	2
Lost	2
General characteristics
Type	Armored cruiser
Displacement	Normal: 9,087 metric tons (8,943 long tons) Full load: 9,875 t (9,719 long tons)
Length	126.5 m (415 ft) o/a
Beam	19.6 m (64 ft 4 in)
Draft	7.9 m (25 ft 11 in)
Installed power	14 × Dürr water-tube boilers 16,200 PS (16,000 ihp)
Propulsion	3 × screw propellers 3 × triple-expansion steam engines
Speed	20 knots (37 km/h; 23 mph)
Range	5,080 nautical miles (9,410 km; 5,850 mi) at 12 knots (22 km/h; 14 mph)
Crew	35 officers 551 sailors
Armament	4 × 21 cm (8.3 in) SK L/40 guns 10 × 15 cm (5.9 in) SK L/40 guns 12 × 8.8 cm (3.5 in) SK L/35 guns 4 × 45 cm (17.7 in) torpedo tubes
Armor	Belt: 100 mm (3.9 in) Turrets: 150 mm (5.9 in) Deck: 40 to 80 mm (1.6 to 3.1 in) Conning tower: 150 mm

The Prinz Adalbert class was a pair of armored cruisers built for the German Kaiserliche Marine (Imperial Navy) under the terms of the First Naval Law. Two ships of the class were built, Prinz Adalbert and Friedrich Carl, between 1900 and 1904. Their design was heavily based on Germany's previous armored cruiser, Prinz Heinrich, with a series of incremental improvements. These included a revised armor layout to improve internal protection, along with an upgraded main battery armament that consisted of four 21 cm (8.3 in) guns instead of the two 24 cm (9.4 in) carried by Prinz Heinrich. The new ships also received more powerful propulsion systems, making them slightly faster. Prinz Adalbert spent her peacetime career as a gunnery training ship while Friedrich Carl initially served as the flagship of the High Seas Fleet's reconnaissance forces. By 1909, she had been replaced by more modern cruisers and joined Prinz Adalbert as a training vessel.

Following the outbreak of World War I in July 1914, both vessels were mobilized; Friedrich Carl was assigned to the cruiser division in the Baltic Sea and was quickly sunk by Russian naval mines off Memel in November, though most of her crew was safely evacuated. Prinz Adalbert initially served in the North Sea, supporting the Raid on Yarmouth in November 1914 before transferring to the Baltic to replace her lost sister. Prinz Adalbert had little better luck, being torpedoed by British submarines twice in 1915, the first, in July, caused serious damage and necessitated lengthy repairs. The second, in October, caused an internal magazine explosion that destroyed the ship and killed almost her entire crew. The sinking killed 672, the greatest single loss of life for the German fleet in the Baltic during the war; there were only 3 survivors of her sinking.