GERMAN BATTLECRUISERS OF WORLD WAR ONE: THEIR DESIGN, CONSTRUCTION AND OPERATIONS PDF, EPUB, EBOOK Gary Staff | 320 pages | 30 Jul 2014 | Pen & Sword Books Ltd | 9781848322134 | English | Barnsley, United Kingdom SMS Derfflinger - Wikipedia The lead ship, Ersatz Yorck , was the only vessel of the three to have begun construction, though she was over two years from completion by the time work was abandoned. The ship was broken up on the slipway and machinery that had been assembled for Ersatz Gneisenau was installed in the first four Type U U-boats. Nevertheless, the work that had gone into the Ersatz Yorck design was not a wasted effort; when the design staff began work on the Scharnhorst -class battleships in the s, they used the plans for Ersatz Yorck as a starting point. The Reichsmarineamt RMA — Imperial Naval Office decided that to meet the requirements set in the law, the Navy should construct one battleship and one battlecruiser every year between and , with an additional unit of both types in and The RMA initially believed the war would be over quickly, but by early , it had become clear that it would not be the case. As a result, it made the decision to use the prescribed construction program to replace the five armored cruisers that had been sunk in the first six months of the war with new battlecruisers, rather than lay down new battleships. The last three of these new battlecruisers were ordered to replace Yorck and the two Scharnhorst -class cruisers , the former having been sunk by German mines in November and the latter pair being sunk at the Battle of the Falkland Islands the following month. The three vessels of the Ersatz Yorck class were to have been members of the Mackensen class , and initial funding for the ships was allocated on 21 February Vizeadmiral Vice Admiral Reinhard Scheer , the commander of the High Seas Fleet , expressed his preference for GK2, the largest and fastest of the versions with a top speed of Some consideration was given to the idea that the new battlecruiser design should represent a merging of the battleship and battlecruiser types—what was later termed a " fast battleship "—a concept Wilhelm II had been pushing for years. The so-called " grosskampfschiff " large combat ship would simplify construction and design work, but Konteradmiral Rear Admiral Georg Hebbinghaus , the head of the General Navy Department, pointed out that under the German Naval Laws, such a change would not be permitted and that the laws would need to be rewritten to allow the new type. Hebbinghaus nevertheless allowed that the design staff had some leeway in warship development that could be used to get around the legal restrictions. In a meeting on 12 August, Hebbinghaus stated that he wanted to build ships that were similar to traditional battleship designs, preferring survivability to offensive power; he argued that the Mackensen s should be cancelled in favor of this new type, since they had been designed before the navy had any war experience on which to base them. Capelle stated that the last three Mackensen s— Ersatz Yorck , Ersatz Scharnhorst , and Ersatz Gneisenau —and Ersatz Friedrich Carl if work had not proceeded too far along, should be reordered as a completely new design, GK6, which he submitted. Scheer objected to the decrease in speed, and for the time being, Hebbinghaus's and Capelle's proposals came to nothing. Another meeting on 24 August concluded that all seven ships of the Mackensen class would be built as designed, the General Navy Department noting that they would "still undoubtedly represent a very valuable addition to the fleet in By this time, much of the construction resources of the German Navy had been redirected to the U-boat fleet, so the new ships could not be completed before ; as a result, the Mackensen s would be inferior to the latest American and British designs. By that time, Ersatz Friedrich Carl had been laid down the previous November, and was too far along to be converted, leaving the last three Mackensen s as the only members available to be rearmed. Indeed, Ersatz Yorck had already been laid down in July. During the re-design process, Scheer requested that the new ships have increased armament, armor, and speed compared to the first four Mackensen s, but owing to the constraints imposed, only the armament could be increased, and the deck armor and speed had to be reduced slightly to keep displacement in check. The length and draft were also increased to keep the ships' speed from falling too much. Since the ships' propulsion systems had already been ordered, they were kept essentially identical to the original Mackensen design, although internal rearrangements allowed the boilers to be trunked into one large funnel rather than the two of the Mackensen s, which conferred several advantages. These included a significant reduction in smoke interference with the spotting tops and additional room to move the tripod mast further aft, which reduced the risk of the mast falling on the conning tower in the event of battle damage and increased the field of view from the spotting top. The Ersatz Yorck -class ships were an enlargement of the previous Mackensen -class ships. They were Ersatz Yorck had the same beam as the earlier vessels, at The Ersatz Yorck -class ships' hulls were to have been constructed with longitudinal steel frames with the outer plating riveted on. The hulls were divided into eighteen watertight compartments. As with all German battlecruisers that had been built, the Ersatz Yorck -class ships would have been equipped with four sets of Parsons steam turbines , [7] each of which drove a 3-bladed screw that was 4. The turbines were supplied with steam by 24 coal-fired Schulz-Thornycroft single-ended boilers and 8 oil-fired Schulz-Thornycroft double-ended boilers. The ships were to have electrical power provided by diesel generators. The Ersatz Yorck s were intended to mount a pair of rudders side by side for steering. However, the areas of the hull between the torpedo bulkhead and the outer wall of the ship were also used for fuel storage. In both designs the turrets were arranged in two superfiring pairs, one forward and the other aft. The guns had to be returned to 2. Each turret was fitted with a stereo rangefinder. The shell allotment was divided between armor piercing and high explosive versions, with 60 of the former and 30 of the latter. These guns were intended for defense against torpedo boats , and were supplied with a total of 2, shells. The question about the main battery for the new battlecruisers was the most pressing; the previous Derfflinger class was armed with This meant that an increase in displacement would necessitate a longer and wider hull to keep any increases in draft minimal and avoid reducing the speed. The constraints on enlarging the hull were compounded by restrictions on width imposed by the locks of the canal in Wilhelmshaven. The design staff suggested using triple or even quadruple gun turrets to keep the displacement under the 30,ton limit. The question of whether the new ships should be powered entirely by oil-fired boilers was less controversial. The design staff was generally in agreement with the standard practice of using coal-fired boilers for two-thirds of the power plant, with the remainder being oil-fired boilers. Coal-fired boilers were preferred because the coal, stored in the sides of the ship, provided additional protection, particularly for the battlecruisers, which carried less armor than their battleship counterparts. This was the same type of construction as in the preceding Derfflinger -class battlecruisers, and was intended to save weight compared to the traditional method of construction, which incorporated both longitudinal and transverse frames. Experience with previous battlecruiser designs led to the adoption of a continuous upper deck, which raised the level of the deck aft. This was necessary because the aft decks of earlier designs were usually awash when steaming at high speed, even in calm seas. The ships were also equipped with a bulbous bow to reduce drag on the hull, the first time the feature was used in the German Navy. Service as a squadron flagship would increase that number by an additional 14 officers and 62 sailors. The vessels carried a number of small boats, including two picket boats, one barge, two launches , two cutters, and three yawls. The ships of the Mackensen class were equipped with four sets of marine-type turbine engines , each of which drove a three-bladed screw propeller that was 4. The ships had 24 coal-fired marine-type single ended boilers and eight oil-fired marine-type boilers. The turrets were mounted in superfiring pairs fore and aft of the main superstructure. The guns were supplied with a total of armor-piercing shells, or 90 per gun. As with other heavy German guns, these weapons used a fore propellant charge in a silk bag with a main charge in a brass case. The ships' secondary battery consisted of fourteen 15 cm 5. The guns had a sustained rate of fire of 7 rounds per minute. The shells were The guns were expected to fire around 1, shells before they needed to be replaced. The ships were also armed with eight 8. Four were arranged around the rear superfiring main battery turret and the other four around the forward conning tower. As was standard for warships of the period, the Mackensen s were equipped with submerged torpedo tubes. The Mackensen - class ships were protected with Krupp cemented steel armor , as was the standard for German warships of the period.