SMS Baden

Recognition drawing of a Bayern-class battleship

In late 1917, light forces of the High Seas Fleet began interdicting British convoys to Norway.[lower-alpha 4] On 17 October the light cruisers Brummer and Bremse intercepted one of the convoys, sinking nine of the twelve cargo ships and the two escorting destroyers before turning back to Germany. On 12 December, four German destroyers ambushed a second British convoy of five cargo vessels and two British destroyers. All five transports were sunk, as was one of the destroyers. Following these two raids, Admiral David Beatty, the commander of the Grand Fleet, detached battleships from the battle fleet to protect the convoys. The German Imperial Navy (Kaiserliche Marine) was now presented with an opportunity for which it had been waiting the entire war: a portion of the numerically stronger Grand Fleet was separated and could be isolated and destroyed. Hipper planned the operation: the battlecruisers of I Scouting Group, along with light cruisers and destroyers, would attack one of the large convoys, while the rest of the High Seas Fleet would stand by, ready to attack the British dreadnought battleship squadron.[17]

At 05:00 on 23 April 1918, the German fleet departed from the Schillig roadstead. Hipper, aboard Baden, ordered wireless transmissions be kept to a minimum, to prevent radio intercepts by British intelligence.[18] At 06:10 the German battlecruisers had reached a position approximately 60 kilometers (37 mi) southwest of Bergen when the battlecruiser Moltke lost her inner starboard propeller, which severely damaged the ship's engines.[19] The crew effected temporary repairs that allowed the ship to steam at 4 kn (7.4 km/h), but it was decided to take the ship under tow. Despite this setback, Hipper continued northward. By 14:00, Hipper's force had crossed the convoy route several times but had found nothing. At 14:10, Hipper turned his ships southward. By 18:37, the German fleet had made it back to the defensive minefields surrounding their bases. It was later discovered that the convoy had left port a day later than expected by the German planning staff.[18]

On 24 May, Baden again steamed to Helgoland, this time to take the commander in chief of the fleet, Admiral Reinhard Scheer, and Grand Duke Friedrich von Baden to visit the island. Only Karlsruhe joined the ship on this voyage.[15] In August, Baden was dry docked for maintenance, and on the 7th of the month, Hipper replaced Scheer as the fleet commander. Baden was refloated on 24 August in preparation for what was to be the last major training exercise of the fleet, conducted on 6 September.[16]

Salvage work in progress on Baden at Scapa Flow. The cruiser Frankfurt is also in view.

As the fleet flagship, Baden was to have taken part in a final fleet action days before the Armistice, an operation which envisioned the bulk of the High Seas Fleet sortieing from their base in Wilhelmshaven to engage the British Grand Fleet. In order to obtain a better bargaining position for Germany, Admirals Hipper and Scheer intended to inflict as much damage as possible on the British navy, whatever the cost to the fleet.[20] Consequently, on 29 October 1918, the order was given to depart from Wilhelmshaven to consolidate the fleet in the Jade roadstead, with the intention of departing the following morning. However, starting on the night of 29 October, sailors on Thüringen mutinied.[21] Early on the 30th, the crew of Helgoland, which was directly behind Thüringen, joined in the mutiny. Both ships surrendered after two torpedo boats arrived and threatened to open fire, and the battleships' crews were taken ashore and incarcerated.[22] The mood of Baden's crew was reported as "dangerous".[23] The rebellion then spread ashore; on 3 November, an estimated 20,000 sailors, dock workers, and civilians fought a battle against the authorities in Kiel in an attempt to secure the release of the jailed mutineers.[24] Meanwhile, on 9 November, the Socialists' red flag was hoisted aboard Baden, which finally convinced Hipper and Scheer to abandon the plan.[24][25]

Baden was not originally intended to be surrendered under the terms of the Armistice, but was substituted for the battlecruiser Mackensen, which lay incomplete and could not put to sea.[13] As a result, instead of joining the High Seas Fleet when it departed for Scapa Flow on 21 November 1918,[26] Baden left Germany on 7 January 1919,[15] and after arriving, most of her crew were taken off the by the light cruiser Regensburg to be returned to Germany.[27] The Royal Navy inspected the ship on 9 January, but many of the technical instruments, including gunnery equipment, had been removed before the ship left Germany.[28] The fleet remained in captivity during the negotiations in Versailles that ultimately produced the treaty that ended the war. A copy of The Times informed Rear Admiral von Reuter that the Armistice was to expire at noon on 21 June 1919, the deadline by which Germany was to have signed the peace treaty. Von Reuter came to the conclusion that the British intended to seize the German ships after the Armistice expired.[lower-alpha 5] To prevent this, he decided to scuttle his ships at the first opportunity. On the morning of 21 June, the British fleet left Scapa Flow to conduct training maneuvers; at 11:20 Reuter transmitted the order to his ships.[29]

Many of the men aboard Baden had been selected to help unload a supply ship that morning, and so were unavailable to open the seacocks, leaving the remaining crewmen insufficient for the task. As a result, Baden was the last major warship to begin the scuttling process, and British forces in the harbor managed to secure the ship, cut her anchor chains, and run her aground before she could sink in deeper water.[13][27] Then-Lieutenant Commander Bruce Fraser led the British sailors who boarded Baden.[30] Baden was the only capital ship not successfully sunk in the scuttling.[13] The ship was refloated on 19 July,[27] after which she was towed to the British naval base at Invergordon.[28]

Baden being towed from Scapa Flow

After the ship arrived in Invergordon, Baden was carefully examined by Royal Navy technicians. Naval engineers inspected the hull, including the screws, bilge keels, and rudders, to determine the water resistance of the hull form. The ship was found to have been approximately as efficient as the British Revenge-class battleships.[31] The ship's armor system was extensively investigated; the British team concluded that the ship had not been modified to incorporate the lessons from the Battle of Jutland of 31 May – 1 June 1916.[32]

The main battery turrets and ammunition magazines were also the subject of intense scrutiny; among the tests conducted was a trial to see how fast the magazines could be flooded—the result was 12 minutes.[33][lower-alpha 6] The gunnery school HMS Excellent ran loading trials on the main battery guns. It was found that the guns could be prepared to fire in 23 seconds, 13 seconds faster than in the Queen Elizabeth-class battleships.[28] The ship's watertight bulkhead and underwater protection systems also particularly interested the inspection team; they paid close attention to the ship's pumping and counter-flooding equipment.[34] Commander W M Phipps Hornby, who lived on board Baden for weeks during the examination, wrote to the naval historian Arthur Marder in 1969 that it was his "considered opinion—which I know coincided with that of others engaged on the same job—that, considered as a fighting machine, anyhow on balance the Baden was markedly in advance of any comparable ship of the Royal Navy".[35]

Painting of Baden sinking as a target ship, August 16, 1921

After the inspection was concluded, it was determined to expend Baden as a gunnery target. In January 1921 the first round of gunnery tests was ordered. The gunners at HMS Excellent fired the new armor-piercing (AP) shells that had been introduced after the Battle of Jutland. This round of tests was used to determine the most efficient ratio of explosives in the detonator caps; the shells fired at Jutland had a tendency to fragment when striking heavy armor rather than penetrate. The monitor HMS Terror moored some 500 yd (460 m) away from Baden to fire her 15 in (38 cm) guns from point-blank range. Baden was made to list to starboard by the removal of coal and armor from the port side, to simulate the effect of a shell striking armor from a plunging angle.[36] The forward-most gun turret had by this time been removed. Terror fired 17 shells of various types into the ship. The Royal Navy concluded after these tests that the new shells were sufficiently powerful to penetrate heavy armor, and were much more effective than the previous versions that had been employed at Jutland.[37] Following the tests, heavy seas caused the ship to sink in the shallow water; after three months she was again raised and docked for repairs. The ship was readied for a second round of testing by August 1921.[38]

The second series of tests was scheduled for 16 August 1921. The monitor HMS Erebus fired a mix of shell types into Baden with her 15 in guns. This time, the shells did not perform as well against Baden's heavy armor; one of the AP shells failed to explode and two semi-AP shells appear to have broken up on impact. Six aerial bombs were also detonated on the ship, though they had been placed on board and were detonated remotely. The bombs did not perform as well as had been expected.[38] Immediately following the second round of gunnery trials, Baden was scuttled. The ship sank in Hurd Deep in a depth of approximately 180 m (600 ft).[13]

The most important finding of the trials on Baden was that the 7-inch (18 cm) thick medium armor was completely useless against large-caliber shells. As a result, the British navy adopted the "all or nothing" armor pioneered by the United States Navy.[39] The "all or nothing" armor theory consisted of protecting the ship's vitals with extremely heavy armor, while leaving the rest of the ship completely unprotected.[40] This system was used on Britain's first post-war class of battleships, the Nelson class.[39]