The three Preussen-class ironclads were authorized under the naval program of 1867, which had been approved by the Reichstag to strengthen the North German Federal Navy in the wake of the Second Schleswig War, when the weak, then-Prussian Navy had been unable to break the blockade imposed by the Danish Navy.
Initially ordered as casemate ships, the vessels were re-designed as turret ships; they were the first uniform class of ironclads built by for the German fleet.

The ship was 96.59 meters (316.9 ft) long overall and had a beam of 16.30 m (53.5 ft) and a draft of 7.12 m (23.4 ft) forward.
Preussen was powered by one 3-cylinder single-expansion steam engine, which was supplied with steam by six coal-fired transverse trunk boilers.
The ship's top speed was 14 knots (26 km/h; 16 mph), at 5,471 metric horsepower (5,396 ihp).
She was also equipped with a full ship rig.
Her standard complement consisted of 46 officers and 454 enlisted men.

She was armed with four 26 cm (10.2 in) L/22 guns mounted in a pair of gun turrets placed amidships.
As built, the ship was also equipped with two 17 cm (6.7 in) L/25 chase guns.
After being rebuilt in 1888–1890, her armament was increased by six and later ten 8.8 cm (3.5 in) L/30 quick-firing guns, a pair of machine guns, and five 35 cm (14 in) torpedo tubes, all submerged in the ship's hull.

Preussen's armor was made of wrought iron and backed with teak.
The armored belt was arrayed in two strakes.
The upper strake was 203 mm (8 in) thick; the lower strake ranged in thickness from 102 to 229 mm (4 to 9 in).
Both were backed with 234 to 260 mm (9.2 to 10.2 in) of teak.
The gun turrets were protected by 203 to 254 mm (8 to 10 in) armor on the sides, backed by 260 mm of teak.
The three Preussen-class ironclads were authorized under the naval program of 1867, which had been approved by the Reichstag to strengthen the North German Federal Navy in the wake of the Second Schleswig War, when the weak, then-Prussian Navy had been unable to break the blockade imposed by the Danish Navy. Initially ordered as casemate ships, the vessels were re-designed as turret ships; they were the first uniform class of ironclads built by for the German fleet.
The ship was 96.59 meters (316.9 ft) long overall and had a beam of 16.30 m (53.5 ft) and a draft of 7.12 m (23.4 ft) forward. Preussen was powered by one 3-cylinder single-expansion steam engine, which was supplied with steam by six coal-fired transverse trunk boilers. The ship's top speed was 14 knots (26 km/h; 16 mph), at 5,471 metric horsepower (5,396 ihp). She was also equipped with a full ship rig. Her standard complement consisted of 46 officers and 454 enlisted men.
She was armed with four 26 cm (10.2 in) L/22 guns mounted in a pair of gun turrets placed amidships. As built, the ship was also equipped with two 17 cm (6.7 in) L/25 chase guns. After being rebuilt in 1888–1890, her armament was increased by six and later ten 8.8 cm (3.5 in) L/30 quick-firing guns, a pair of machine guns, and five 35 cm (14 in) torpedo tubes, all submerged in the ship's hull. 
Preussen's armor was made of wrought iron and backed with teak. The armored belt was arrayed in two strakes. The upper strake was 203 mm (8 in) thick; the lower strake ranged in thickness from 102 to 229 mm (4 to 9 in). Both were backed with 234 to 260 mm (9.2 to 10.2 in) of teak. The gun turrets were protected by 203 to 254 mm (8 to 10 in) armor on the sides, backed by 260 mm of teak.
SMS Preussen (1873)