Less than two years after the first members of the class entered service, the ships were rendered obsolescent by the British all-big-gun battleship Dreadnought, which curtailed their careers.

Lothringen and Hessen were slated to be decommissioned in 1914, but the outbreak of World War I in July prevented this and they remained in service with the High Seas Fleet.

Lothringen and Preussen were converted into parent ships for minesweepers to clear the minefields in the North Sea that had been laid during the war, but the other three were modernized in the early 1920s and served with the fleet into the 1930s.

Hessen remained in service until late 1934, when she was decommissioned and converted into a radio-controlled target ship, a role she filled through World War II.

The 24 cm guns were, however, the largest weapons for which Krupp, the supplier of naval artillery to the Kaiserliche Marine (Imperial Navy), had developed quick-firing technology.

But by the time design work on the Braunschweig class began, Krupp had developed a quick-firing 28 cm (11 in) gun, and so the naval command decided to adopt it for the new ships.

[5] Dreadnought's revolutionary design rendered every capital ship of the German navy obsolete, including the Braunschweigs.

[6] Also, the 17 cm guns proved to be something of a disappointment in service, since the larger shells were significantly heavier and thus harder to load manually, which reduced their rate of fire.

[7] The beam was constrained by logistical considerations, as it was the widest that could be accommodated by the locks at the entrance to the Kaiserliche Werft (Imperial Shipyard) in Wilhelmshaven.

[9] The ships of the Braunschweig-class were propelled by three-shaft triple-expansion steam engines that were rated at 16,000 metric horsepower (15,781 ihp; 11,768 kW).

During trials, however, the engines produced between 16,478 and 16,980 metric horsepower (16,253 and 16,748 ihp; 12,120 and 12,489 kW), and a top speed between 18.2 and 18.7 knots (33.7 and 34.6 km/h; 20.9 and 21.5 mph).

The ships of the class could steam 5,200 nautical miles (9,600 km; 6,000 mi) at a cruising speed of 10 knots (19 km/h; 12 mph), with the exception of Hessen.

Hessen suffered from unstable steering, which increased fuel consumption and shortened her operational range to 4,530 nmi (8,390 km) at 10 knots (19 km/h; 12 mph).

[1] The main armament comprised four 28 cm SK L/40[b] quick-firing guns in hydraulically operated twin turrets.

[10] The secondary battery consisted of fourteen 17 cm SK L/40 quick-firing guns, four of which were mounted in single turrets amidships, with the remaining ten in casemates around the superstructure.

The guns fired 7 kg (15.4 lb) shells at a muzzle velocity of 770 m/s (2,526 ft/s), and could be elevated to 25 degrees for a maximum range of 9,090 m (9,940 yd).

The main armored belt was 225 mm (8.9 in) thick in the central portion of the ship where it protected the ammunition magazines and propulsion machinery spaces.

The fleet was on its summer cruise to Norway during the crisis, and word of the Austro-Hungarian ultimatum to Serbia forced the ships to return home early to prepare for the coming conflict.

[27][28] At the start of World War I, Braunschweig and Elsass were reactivated and assigned to IV Battle Squadron under the command of Vice Admiral Ehrhard Schmidt, tasked with coastal defense duties.

Schmidt decided to withdraw his forces when it became apparent that the mine-clearing had taken too long, and there was not sufficient daylight left for the minelayer Deutschland to lay a minefield of its own in Moon Sound to block the northern entrance to the gulf.

[32] In the meantime, the other three ships were still serving in II Battle Squadron, where they participated in the fleet sorties conducted in the first two years of the war.

Preussen was on rotation as the guard ship in the Danish straits (and had been replaced as flagship by the battleship Deutschland) and Lothringen was in poor condition and in dire need of repair.

[33] The loss of the pre-dreadnought Pommern during the battle highlighted the vulnerability of the older battleships, and coupled with their slow speed, convinced the German naval command to withdraw them from front-line service.

The Treaty of Versailles specifically stated in Article 181 that the Reichsmarine would be permitted to retain eight battleships of the "Lothringen or Deutschland types", six of which could be kept in commission.

[34] Three of the ships—Braunschweig, Elsass, and Hessen—saw active duty with the fleet while the other two vessels—Preussen and Lothringen—were instead converted into parent ships for minesweepers, since Germany was required by the Treaty of Versailles to clear the extensive minefields that had been laid in the North Sea during the war.

During this period, she served as the flagship of the Marinestation der Nordsee (Naval Station of the North Sea) and later the Linienschiffsdivision (Battleship Division).

The work involved cutting away most of the superstructure, removing the armament, and replacing the old propulsion machinery with steam turbines.