Nassau-class battleship

The Nassau class were a group of four German dreadnought battleships built for the Imperial Navy. They were the German response to the introduction of the "all big gun" British HMS Dreadnought (1906). The class was composed of SMS Nassau, SMS Rheinland, SMS Posen, and SMS Westfalen. All four ships were laid down in mid-1907, and completed between May and September 1910. Compared to their British contemporaries, the Nassau-class ships were lighter and had a wider beam. They were two knots slower, because the German ships retained vertical triple-expansion engines as opposed to the high-power turbine engines adopted by the British. The ships also carried smaller main guns—11-inch (280 mm) guns rather than the 12-inch (305 mm) guns mounted on the British ships.

After their commissioning into the German fleet, all four ships served as a unit: the II Division of I Battle Squadron. Two of the ships, Nassau and Posen, took part in the inconclusive Battle of the Gulf of Riga in 1915, during which they engaged the Russian pre-dreadnought RUSSIAN BATTLESHIP Slava. The Nassau-class ships took part in the Battle of Jutland on 31 May and 1 June 1916 as the II Battle Squadron; they suffered only a handful of secondary battery hits and limited casualties. At the end of the First World War, the four ships were seized as war prizes by the victorious Allied powers and sold for scrapping.

Development
In 1906, the launch of the "all big gun" HMS Dreadnought (1906) made all other battleships then in existence obsolete. The First Naval Amendment to the 1900 German Naval Law was passed in 1906 prior to the launch of Dreadnought; Admiral Alfred von Tirpitz had originally requested six new battleships and six armored cruisers, along with a number of miscellaneous smaller craft. The launch of the revolutionary Dreadnought meant that any future battleships that could compete with her would be significantly more expensive than the older pre-dreadnought battleships. Opposition to budget increases in the Reichstag forced Tirpitz to reduce his request to six armored cruisers—one of which was to have been placed in reserve—and 48 torpedo boats, dropping his request for new battleships completely; the reduced proposal was voted through on 19 May 1906. A week after the amendment was passed, funds for two 18,000-ton battleships and a 15,000-ton armored cruiser were allocated to the Navy. Funds were also provided to widen the Kaiser Wilhelm Canal and enlarge dock facilities to accommodate the larger ships.

A debate ensued in the Reichsmarineamt (Naval Office) over the construction of the new ships. Tirpitz favored following the Royal Navy by building dreadnought battleships and battlecruisers as well. Tirpitz saw it as an opportunity to break Britain's commitment to the "two power standard". Tirpitz also intended to use the funds that had been allocated for armored cruisers to build battlecruisers instead, although they were still to be classified as armored cruisers.

Nassau and Westfalen were the first dreadnoughts ordered under the 1906–07 program; the armored cruiser SMS Blücher was ordered along with them. The Second Naval Amendment to the 1900 Naval Law was passed on 27 March 1908; this amendment included a budget of 1 billion marks, and provisions that reduced the lifespan of battleships from 25 years to 20. This had the effect of necessitating the replacement of the coastal defense ships of the and SMS Oldenburg (1884) classes, as well as the pre-dreadnoughts of the. The s (first put into service in the late 1870s) also needed replacement, as they were already obsolete, even under the 25-year standard. The four Sachsens were to be replaced by the Nassau class. The second pair of ships in the Nassau class, Posen and Rheinland, were ordered under the 1907–08 building program.

General characteristics
The ships were 146.1 m long, 26.9 m wide, and had a draught of 8.9 m. The ships had a length to width ratio of 5.45, which was somewhat "stubby" compared to contemporary designs. To some extent, the greater than normal width was due to the four wing turrets, which necessitated a wider hull. They displaced 18,570 tons with a standard load, and 21,000 tons fully laden. The ships had 19 watertight compartments, with the exception of Nassau, which only had 16. All four ships had a double bottom for 88 percent of the keel. The ships carried a number of boats, including a picket boat, 3 admiral's barges, 2 launches, 2 cutters, and 2 dinghies.

As designed, the ships did not handle particularly well, even in calm seas, and their motion was quite stiff. The ships experienced severe rolling, due to the weight of the wing turrets. The heavy wing turrets caused the ships to have a large metacentric height, which should have made them very stable gun platforms, but their roll period proved to coincide with that of the average North Sea swell. Bilge keels were later added, which helped to improve the rolling problem. Despite the tendency to roll, the Nassau-class ships were maneuverable and had a small turning radius. They suffered minor speed loss in heavy seas, but up to 70 percent at hard rudder. The roll keels that had been fitted to improve handling caused a portion of the speed loss at hard rudder.

Propulsion
The German Navy was slow to adopt the advanced Parsons turbine engines used in the British Dreadnought, primarily due to the resistance of both Admiral von Tirpitz and the Navy's construction department. In 1905, the latter stated that the "use of turbines in heavy warships does not recommend itself." The Nassau class therefore retained obsolete vertical triple expansion engines rated at 22,000 ihp. Each of the three shafts drove a 3-bladed screw that was 5 m (5.46 yd) in diameter. Designed top speed was 19.5 knots. On trials, the ships attained 20 to 20.2 knots on 26,224 to 28,117 ihp. By comparison, Dreadnought's steam turbines provided a rated speed of 21 knots.

Steam was provided by 12 Schulz-Thornycroft boilers, each of which had 2 fireboxes, for a total of 24. The machinery was divided into three engine and six boiler rooms. The wing turrets and their magazines further divided the machinery into three separated groups, thereby increasing survivability. The ships carried 2,700 tons of coal, and were later modified to carry an additional 160 tons of oil that was to be sprayed on the coal, to increase its burn rate. Electrical power was provided by eight turbo-generators, producing 1,280 kW at 225 V.

Armament


The vertical triple expansion engines consumed large amounts of internal space that could otherwise have been used for magazines. Without sufficient magazine capacity to support superfiring centerline turrets, designers were compelled to distribute six main turrets in an unusual hexagonal configuration. Two twin turrets were mounted fore and aft (one on each end), and two were mounted on each flank of the ship. Firing directly forward and aft, the ships could bring 6 guns to bear, and 8 on the broadside; this was the same theoretical capability as Dreadnought, but the Nassau-class ships required two additional guns to achieve it. It was considered that this arrangement provided a useful reserve of heavy guns that were shielded from enemy fire.

Each ship carried twelve 28 cm SK L/45 guns. The wing turrets were Drh LC/1906 mounts, as were the centerline turrets on the first two ships of the class, Nassau and Westfalen. Posen and Rheinland carried their centerline guns in Drh LC/1907 turrets, which had a longer trunk than the LC/1906 design. The Drh LC/1906 turrets and 11-inch SK/L45 guns were designed specifically for the new German dreadnoughts in 1907. Both mountings allowed for elevation up to 20 degrees, but the LC/1907 mounts could depress an additional two degrees, down to −8. The main battery propellant magazines were placed above shell rooms, with the exception of the centerline turrets of Nassau and Westfalen. These guns fired 666 lb shells, with a 57 lb (26 kg) fore propellant charge in silk bags and a 174 lb (79 kg) main charge in a brass case. The guns fired the shells at a muzzle velocity of 2,805 ft/s (855 m/s), and had a maximum range of 22,400 yards (20,500 m). At a range of 13,100 yards (12,000 m), the 11 in shells would penetrate up to 7.9 in (200 mm) of belt armor.

The ships' secondary armament consisted of twelve 15 cm SK L/45 guns, which were mounted in casemates. The guns fired 99.9 lb shells at a muzzle velocity of 2,740 ft/s (835 m/s). The guns could be elevated to 19 degrees, which provided a maximum range of 16,350 yards (14950 m). The ships also carried sixteen 8.8 cm SK L/45 guns, also in casemates. These guns fired a 22-lb projectile at 2,133 ft/s (650 m/s), and could be trained up to 25 degrees for a maximum range of 10,500 yards (9,600 m). After 1915, two 8.8 cm guns were removed and replaced by two 8.8 cm Flak guns, and between 1916 and 1917, the remaining twelve 8.8 cm casemated guns were removed. These anti-aircraft guns fired a slightly lighter 21.2 lb shell at 2,510 ft/s (765 m/s). They could be elevated to 45 degrees and could hit targets 12,900 yards (11,800 m) away. The Nassau-class ships were also armed with six 45 cm submerged torpedo tubes. One tube was mounted in the bow, another in the stern, and two on each broadside, on either ends of the torpedo bulkhead.

Armor
The Nassau-class ships were equipped with Krupp cemented steel armor. The ships had an armored belt that was 30 cm thick at its strongest, where it protected the ship's vitals in the center, and as thin as 8 cm in less critical areas, such as the bow and stern. Behind the main belt was a torpedo bulkhead 3 cm thick; there was some difficulty mounting the torpedo bulkhead, due to the four wing turrets and their barbettes. The ships' decks were armored, between 5.5–8 cm (2.1–3.1 in) thick. The forward conning tower had a roof that was 8 cm thick, and sides 40 cm thick. The aft conning tower was less well protected, with a 5 cm thick roof and 20 cm sides. The main battery turrets had roofs that were 9 cm thick, and 28 cm sides. The casemated secondary battery had 16 cm worth of armor protection, and 8 cm thick gun shields. The ships were also fitted with anti-torpedo nets, but these were removed after 1916.

Construction
Four ships of the class were ordered, under the provisional names Ersatz Bayern, Ersatz Sachsen, Ersatz Württemberg, and Ersatz Baden, as replacements for the four old s. The first ship of the class, SMS Nassau, was laid down on 22 July 1907 at the Kaiserliche Werft in Wilhelmshaven, launched on 7 March 1908, and commissioned into the fleet on 1 October 1909. SMS Westfalen was laid down less than a month later, on 12 August 1907 at the AG Weser shipyard in Bremen. The ship was launched on 1 July 1908, and commissioned on 16 November 1909.

SMS Rheinland, the third ship of the class, was actually the first to be laid down, on 1 June 1907 in the AG Vulcan shipyard in Stettin. Construction of Rheinland proceeded slower than Nassau and Westfalen, and so the ship was launched later, on 26 September 1908. Rheinland joined the fleet on 30 April 1910. SMS Posen, the last ship of the class, was laid down at the Germaniawerft shipyard in Kiel on 11 June 1907. The ship was not launched until 12 December 1908, and did not join her sisters until 31 May 1910.

Service history
The Nassau-class ships operated as a unit in the High Seas Fleet: the II Division of the I Battle Squadron. The ships of the class participated in a number of fleet operations in the North Sea, including the action on 31 May 1916 that resulted in the Battle of Jutland. The ships also saw limited service in the Baltic Sea, including the abortive Battle of the Gulf of Riga in August 1915.

Battle of the Gulf of Riga
In August 1915, the German fleet attempted to clear the Gulf of Riga, in order to facilitate the capture of Riga by the German army. To do so, the German planners intended to drive off or destroy the Russian naval forces in the gulf, which included the pre-dreadnought RUSSIAN BATTLESHIP Slava and a number of gunboats and destroyers, and lay a series of minefields in the northern entrance to the gulf. The fleet that assembled to assault the gulf included the four Nassau-class ships, the four s, and the battlecruisers SMS Von der Tann, SMS Moltke, and SMS Seydlitz. The eight battleships were to provide cover for the forces engaging the Russian flotilla. The first attempt on 8 August was unsuccessful, as it had taken too long to clear the Russian minefields to allow the minelayer SMS Deutschland (1914) to lay a minefield of her own.

On 16 August, a second attempt was made to enter the gulf: Nassau and Posen, four light cruisers, and 31 torpedo boats breached the defenses to the gulf. On the first day of the assault, the German minesweeper T46 was sunk, as was the destroyer SMS V99. On 17 August, Nassau and Posen engaged in an artillery duel with Slava, resulting in three hits on the Russian ship that prompted her withdrawal. After three days, the Russian minefields had been cleared, and the flotilla entered the gulf on 19 August, but reports of Allied submarines in the area prompted a German withdrawal from the gulf the following day.

Battle of Jutland


The ships took part in the inconclusive Battle of Jutland on 31 May – 1 June 1916. For the majority of the battle, the I Battle Squadron formed the center of the line of battle, behind Rear Admiral Behncke's III Battle Squadron, and followed by Rear Admiral Mauve's elderly pre-dreadnoughts of the II Battle Squadron. Posen served as the division flagship, under the command of Rear Admiral W. Engelhardt.

At around midnight on 1 June, Nassau came in contact with the British destroyer HMS Spitfire (1912), and in the confusion, attempted to ram her. Spitfire tried to evade, but could not maneuver away fast enough, and the two ships collided. Nassau fired her forward 11-inch guns at the destroyer, but they could not depress low enough for Nassau to be able to score a hit. Nonetheless, the blast from the guns destroyed Spitfire's bridge. At that point, Spitfire was able to disengage from Nassau, and took with her a 20-foot (6 m) portion of Nassau's side plating. The collision disabled one of her 5.9-inch guns, and left an 11.5-foot (3.5 m) gash above the waterline; this slowed the ship to 15 knots until it could be repaired. At approximately the same time, Posen accidentally rammed the light cruiser SMS Elbing and holed her below the waterline. Elbing was damaged so severely that her engine room was completely flooded and she was unable to move; the captain of the ship ordered Elbing be scuttled to prevent her capture by the British.

Shortly after 01:00, Nassau and SMS Thüringen encountered the British armored cruiser HMS Black Prince (1904). Thüringen opened fire first, and pummeled Black Prince with a total of 27 heavy-caliber shells and 24 shells from her secondary battery. Nassau and SMS Ostfriesland joined in, followed by SMS Friedrich der Grosse (1911).

"[Black Prince] presented a terrible and awe-inspiring spectacle as she drifted down the line blazing furiously until, after several minor detonations, she disappeared below the surface with the whole of her crew in one tremendous explosion."

The wreck of the ship was directly in the path of Nassau; to avoid it, the ship had to steer sharply towards the III Battle Squadron. It was necessary for the ship to steam at full speed astern in order to avoid a collision with SMS Kaiserin. Nassau then fell back into a position between the pre-dreadnoughts SMS Hessen and SMS Hannover.

Following the return to German waters, Nassau, Posen, and Westfalen, along with the Helgoland-class battleships SMS Helgoland and Thüringen, took up defensive positions in the Jade roadstead for the night. The Nassau-class ships suffered only a handful of secondary battery hits from the opposing Grand Fleet; Nassau was hit twice, Westfalen and Rheinland each once, and Posen escaped completely unscathed. Not a single ship of the four was struck by a heavy-caliber shell.

Later operations
Less than three months after Jutland, Westfalen was torpedoed by the British submarine HMS E23 on 19 August 1916, but suffered minimal damage and was soon repaired. In 1918, Westfalen and Rheinland were detached from the High Seas Fleet and ordered into the Baltic Sea. Finland was revolting against Russian rule, and the two ships were to aid the Finns in the civil war. On 11 April at approximately 07:30, Rheinland ran aground off the Åland Islands. Approximately 6,000 tons of guns, belt armor, and coal were removed in order to lighten her enough to be refloated, which was not accomplished until 9 July. Rheinland was never repaired, and instead saw the remainder of her service as a barracks ship in Kiel.

Following the end of the First World War in 1918, eleven battleships of the, , and es and all five battlecruisers, along with a number of light cruisers and destroyers, were interned in Scapa Flow, while their fate was determined in the negotiations over the Treaty of Versailles. The Nassau and s were left in Germany. Following the scuttling of the German fleet in June 1919, all four ships were allotted to the victorious Allied powers as replacements for the scuttled ships. Nassau was ceded to Japan, Britain received Westfalen and Posen, and Rheinland was sold directly to the breakers at Dordrecht. Between 1920 and 1924, Westfalen was scrapped at Birkenhead and the remaining ships were scrapped at Dordrecht.