The class was a class of two "all-big-gun" battlecruisers of the German Imperial Navy built between 1909 and 1911. Named and , they were similar to the previous battlecruiser , but the newer design featured several incremental improvements. The s were slightly larger, faster, and better armored, and had an additional pair of guns.
Both ships served during World War I. participated in several major battles with the rest of the High Seas Fleet, including the battles of Dogger Bank and Jutland in the North Sea, and the Battle of the Gulf of Riga and Operation Albion in the Baltic Sea. At the end of the war, was interned with the majority of the High Seas Fleet at Scapa Flow while the ships' fate was being discussed during peace treaty negotiations. The ships were scuttled on 21 June 1919 to prevent their seizure by the Allies.
was stationed in the Mediterranean at the start of the war; she escaped from pursuing Royal Navy ships to Constantinople. The ship, along with the light cruiser , was transferred to the Ottoman Navy soon after arrival. Strategically, played a very important role: she helped bring the Ottoman Empire into the war as a member of the Central Powers, and by acting as a fleet in being the ship prevented Anglo-French attempts to force the Bosporus, and similarly stymied a possible advance by the Russian Black Sea Fleet. was retained by the new Turkish government after the war. Only slightly modified from her original configuration, the ship remained on active service with the Turkish Navy until being decommissioned on 20 December 1950; she was stricken from the Navy register on 14 November 1954. The ship was unsuccessfully offered for sale to the West German government in 1963. Without a group willing to preserve her as a museum, the ship was sold to M.K.E. Seyman in 1971 for scrapping. She was towed to the breakers on 7 June 1973, and the work was completed in February 1976.
Development
In early 1907, the German naval command began to discuss ideas for the next design for a battlecruiser to follow the preceding vessel (before work on that ship had even begun). The new ship, provisionally titled "G", would be ordered under the terms of the 1906 Naval Law. The question of armament came to the fore, in large part because the corresponding dreadnought battleship design, the , had its main battery guns increased from to . In a meeting on 23 April, Admiral Alfred von Tirpitz, the state secretary of the (RMA—Imperial Navy Office), issued general guidance that the new battlecruiser should be an improvement over Von der Tann, but did not specify requirements. The RMA's Construction Department presented its ideas at a subsequent meeting on 2 May. They argued that while the available budget would allow the eight 28 cm guns to be replaced by an equal number of 30.5 cm weapons, the fact that the German fleet would likely be outnumbered by its opponents meant that a greater number of guns was more important, since it would make it easier to fight more than one ship at a time. Therefore, they advocated increasing the number of guns to twelve, but keeping the 28 cm caliber.
The next meeting took place on 7 May; there, Admiral August von Heeringen, the head of the General Navy Department, stated that the same logic that drove the navy to increase the caliber of the battleships' armament should apply to the next battlecruiser. From a tactical perspective, the new ship would be needed to fight in the line of battle against battleships, so the increased firepower was necessary. He argued that an armament of ten 30.5 cm guns could be arranged on the ship and remain within budgetary constraints. He requested the design staff investigate the potential for such a ship carrying its armament in the same pattern as the British . He specified that armor protection was to remain as on Von der Tann, and the top speed should be at least . Several preliminary designs were prepared with different configurations, including an eight-gun 30.5 cm ship, a ten-gun 28 cm vessel, and an alternative with eight 28 cm guns but improved armor protection. Tirpitz agreed with the Construction Office and recommended the ten-gun ship, which Kaiser Wilhelm II approved on 28 May 1907.
With the caliber argument settled and general requirements agreed upon, the project was handed over to the Construction Department to take the plan, named "G2i", and produce a finalized design. This work took longer than expected, since the design staff was already busy completing the design for the Helgoland class, and there were not enough naval architects to work on both tasks simultaneously. At the same time, some discussion was still happening over an alternative, "G5", which was in essential respects a repeat of Von der Tann, but with improved armor protection. At a conference on 26 March 1908, Tirpitz informed the other senior naval leaders that "G5" was politically infeasible, since it would increase displacement over the prescribed limit of . He ordered the design staff to proceed with "G2i", but to make improvements to the armor if it was possible. Soon thereafter, two of the designers wrote a memorandum to Tirpitz in which they objected to the repeated single-ship classes, citing the excessive workload the practice created. They requested that the next battlecruiser simply repeat the Von der Tann design. Nevertheless, the design staff soon completed work on the "G2i" project, which was in turn approved by Wilhelm II.
During the design process, several refinements to "G" were made. These included adding a pair of guns to the secondary battery, the removal of four guns from positions that were deemed to be unworkable, and planned lattice masts were replaced with lighter pole masts. In addition, the citadel was revised, armor thicknesses were increased, and ammunition allotments were reduced to save weight. Internally, the boiler rooms were rearranged into a wider but shorter layout to shorten the area that needed to be protected by heavy side armor. Several significant changes were made to the hull form, including the discontinuation of the old-fashioned ram bow. Lastly, Tirpitz decided to change the traditional side-by-side arrangement of the two rudders to an in-line layout, which reduced hydrodynamic losses, eliminated vibration, and improved handling and speed.
It was initially planned to build only one ship of the new design, but due to the strain on the Navy design staff, it was decided to build two ships of the new type. They were assigned under the contract names of "G" and "H". As Blohm & Voss made the lowest bid for "G", the company also secured the contract for "H". The former was assigned to the 1908–1909 building year, while the latter was assigned to 1909–1910. The contract for "G" was awarded on 17 September 1908, under building number 200. The keel was laid on 7 December 1908, and the ship was launched on 7 April 1910. "G" was commissioned on 30 September 1911 as SMS . The ship's namesake was Field Marshal Helmuth von Moltke, the Chief of Staff of the Prussian Army in the mid 19th century. "H" was ordered on 8 April 1909 with the building number 201. The ship's keel was laid on 12 August 1909; the hull was launched on 28 March 1911. After fitting-out, "H" was commissioned on 2 July 1912 as SMS . The ship was named for August Karl von Goeben, a Prussian general who served during the Franco-Prussian War.
Design
General characteristics The -class ships were long overall, wide, and had a draft of fully loaded. The ships displaced normally, and fully loaded. The -class ships had 15 watertight compartments and a double bottom that ran for 78% of the keel of the ships. They had a long forecastle deck that ran most of the length of the ship, terminating at the rear superfiring gun turret. Their superstructure was fairly small, consisting of a large, armored conning tower forward and a smaller, secondary conning tower aft. Later in her career, Moltke had an enclosed admiral's bridge installed atop her forward conning tower. The ships' interior decks were covered with linoleum, while exterior surfaces received of teak planking. Both vessels were fitted with eight searchlights for use in night fighting; four were placed on the forward funnel and the other four were located on the aft conning tower. Moltke carried another two smaller lights for signaling purposes, while Goeben had only one.
Steering was controlled by two rudders placed in line. The ships were considered to handle well, with gentle movement even in heavy seas. However, they were slow to respond at the helm and were not particularly maneuverable at low speeds. In fact, the ships had a tighter turning circle at higher speeds; at , their turning circle was , but at , the circle decreased slightly to . When attempting to initiate a turn from being stopped, the rudders had no effect, so the turn had to be initiated by differentially running the screws. The ships lost up to 60% speed and heeled 9 degrees at full rudder.
The ships had a standard crew of 43 officers and 1010 men. While served as the flagship of I Scouting Group, this increased by 13 officers and 62 men. While serving as the second command flagship, the ship carried an additional 3 officers and 25 men to the standard complement. The ships had several smaller boats, including one picket boat, three barges, two launches, two yawls, and two dinghies. The boats were carried amidships near the wing turrets, which exposed them to significant blast effects when those guns were fired. During wartime operations, the boats were generally left ashore. Equipment to handle a floatplane was installed aboard Moltke in 1915.
Propulsion and were powered by four-shaft Parsons turbines in two sets and 24 coal-fired Schulz-Thornycroft boilers, divided into four boiler rooms. The two aftmost rooms were divided by internal bulkheads to contain flooding, but space constraints prevented the forward two from being subdivided. The boilers consisted of one steam drum and three water drums each and produced steam at . They were vented through two large funnels spaced widely apart. Moltke had a funnel cap installed after it became evident that smoke would otherwise interfere with the foremast; Goeben was completed with the cap. After 1916, the boilers were supplemented with tar-oil sprayers that were used to increase the burn rate of the low quality lignite coal available to Germany. The Parsons turbines were divided into high- and low-pressure pairs. The low-pressure turbines were the inner pair, and were placed in the aft engine room. The high-pressure turbines were on either side of the low-pressure pair, and were located in the forward wing rooms. The turbines powered four three-bladed screw propellers, in diameter. The starboard screws turned clockwise and the port pair turned counter-clockwise (when viewed from astern).
The ships' power-plants delivered a rated and a top speed of . However, in trials attained and a top speed of ; s power-plant produced only a slightly lower horsepower and top speed. At , the ships had a range of . The -class ships were equipped with 6 turbo generators that delivered of power at 225 volts. The ships were designed to carry 1,000 tons of coal, although in practice they could store up to 3,100 tons. Fuel consumption on the six-hour forced trial was 0.667 kilogram per horsepower-hour at , and 0.712 kg per horsepower-hour at , respectively for the two ships.
Armament