Finalizing the 20,000 Ton Design

this phenomenon had been responsible for the uncontrollable fi res on the Russian ships at the Battle of Tsushima when burning coal dust had ignited the fl ammable paints used by the Russians. Th ese results inspired the Germans to make a study of the fl ammability of diff erent kind of paints. Gunnery tests on the Meppen test ground also showed that 28 cm APC projectiles fi red from 4,000 meters easily penetrated the 300 mm belt armor, the deck armor and the torpedo bulkhead of the Nassau section. As a result, the Germans decided to increase the thickness of the belt armor to 350 mm on their third dreadnought class (Kaiser class).128

Th e Germans carried out expensive underwater explosion tests from 1906 on test beds which represented full scale battleship and battlecruiser sections. Th ese tests were carried out with the newest 50 cm torpedo warheads which were fi lled with a 125 kg explosive charge. Th ese tests demonstrated that the armored torpedo bulkheads (30-40 mm thick) near to the side shell plating did not work well; the splinters from the breaking armored bulkhead caused by the explosion pierced the next, thin bulkhead. Th e Germans concluded that 4-4.5 m was the proper distance between the side shell plating and the armored bulkhead. Th ey also found that the coal stored between the inner plating of the double hull and the torpedo bulkhead successfully absorbed a part of the energy of the explosion. Th e other important factor of the underwater protection was the minute subdivision of the German dreadnoughts. Th e Germans subdivided their dreadnoughts with as many watertight compartments as possible and eliminated doors in the watertight bulkheads.129 Koudelka showed to Tirpitz one of the Popper’s design (No. VI), which had ten 30.5 cm guns in fi ve twin turrets, all on the centerline. Th is was similar to the British Orion). Tirpitz criticized the design’s torpedo protection (torpedo bulkhead was only 2 m from the side shell plating) and pointed to the German test results again. In his opinion such an armament was too heavy for a 20,000 ton battleship. Tirpitz advised to sacrifi ce a gun turret and increasing the thickness of the belt armor to 300 mm and decreasing the casemate armor to 150 mm. Tirpitz proposed for this design a turret arrangement similar to that of the British battlecruiser Invincible. Before Koudelka left Tirpitz’s offi ce the Admiral called his attention again to the importance of the torpedo protection and the watertight bulkheads.130

Koudelka handed his top secret report in a sealed envelope on 3 May to Montecuccoli personally.131 However, for unknown reasons it appears that little was done with this information during the fi nal stage of the design of the 20,000 ton battleships to improve the torpedo protection system. Austria-Hungary’s fi rst dreadnoughts were built using Popper’s torpedo protection system of which Koudelka’s report clearly showed that it was fl awed in light of German test results. Th is led to the tragic loss of two of the four battleships.

Finalizing the 20,000 Ton Design

Two days after Koudelka handed his secret report to Montecuccoli, the STT sent to the Marinesektion a radically new design, designated as No VIII, which had been made at the personal request of Montecuccoli. Th e new design was armed with twelve 30.5 cm/45 guns in four triple turrets and with ten 15 cm guns in casemates. Th e thickness of the design’s belt armor was 230 mm and she had two tripod masts.132 Th is was the fi rst design which resembled the battleships as they were actually built.

In the course of the design process of the new battleship, more and more details of the Italian battleship design became known which infl uenced the Austro-Hungarian plans to a great extent. In December 1908, it had come to the light that the Italian dreadnought was to be armed with twelve 30.5 cm guns, arranged in four triple turrets. Th e original idea of triple turrets came from Russia: the Russian Navy drew up their specifi cation in December 1907 for battleships which would carry twelve heavy guns in four triple turrets, all on the centerline. Th e Russians believed that broadside fi re was much more important than end on fi re, so they prescribed in their specifi cation the “linear” arrangement of the turrets distributed over the length of the ship. Th e Italian naval constructor, Vittorio Cuniberti was among the fi fty-one competitors for the contract, and imported the idea and the arrangement of the turrets. Th e fi rst Italian dreadnought, the Dante Alighieri, was designed by Edoardo Masdea along the Russian principles, but the Italian ship had a raised forecastle deck.

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25 Th e STT/Popper design No VIII armed with twelve 30.5 cm guns in four triple turrets

Th e turret arrangement of the Austro-Hungarian No VIII diff ered from the Italian Dante Alighieri’s: the Austro-Hungarian ship had two turrets on the bow and two turrets on the stern, the second superimposed over the fi rst and the third over the fourth turret. Th is arrangement provided heavier bow and stern fi re and better allocation for the machinery spaces and the secondary battery, but on the other hand this arrangement put greater stress on the ends of the hull and the ship became top-heavy.

From the existing fi les of the design process of the fi rst Austro-Hungarian dreadnoughts it is impossible to fi nd out exactly when the Navy began to consider the use of triple turrets. Th e fi rst mention of triple turrets is from 14 April 1909 in a note written by hand on a separate small, unsigned piece of paper: “triple turret 635 tons”.133 When Kou delka visited the Reichsmarineamt in Berlin in April, Admiral Tirpitz already knew that the Austro-Hungarian Navy was considering the idea of using triple turrets.134 Th e Germans also were interested in triple turrets and the Austro-Hungarian Navy gave permission to the German Navy to examine the turrets of the Viribus Unitis during a gunnery practice in July 1913.135 It is clear that many offi cers, naval architects and engineers in the Navy were not enthusiastic about the triple turrets;136 it seems that it was rather a personal choice of Mon tecuccoli who wanted to copy the armament of the Italian battleship. To examine the possible problems of a triple turret (ammunition supply of the central gun, ventilation) the Škoda built a large-size model of a triple turret137 which is today on display at the Heersgeschichtliche Museum in Vienna.

On 9 June 1909, the Navy drew up new specifi cations for the dreadnoughts: displacement of 20,500 tons, belt armor of 280 mm, casemate armor of 160 mm, twelve 30.5 cm/45 main battery, twelve 15 cm/50 secondary battery, four underwater torpedo tubes, Parsons steam turbines and coal

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26 Th e 30.5 cm/45 triple turret model made by Škoda. Note the projectile with AP cap but without ballistic cap on the loading car. Note also the connecting trays between the main and the auxiliary ammunition hoists

fi red Yarrow boilers with oil-spraying, two masts, one for the fi re control position and one for the searchlights. Th e design also showed an aft conning tower and two armored fi re control positions for the secondary battery. Th ese specifi cations were sent to the MTK and the STT.138

Th e specifi cation on the torpedo protection system was the following: “About the Minenpanzer (torpedo bulkhead) it is to be mentioned that it may be advantageous to build a longitudinal bulkhead between it and the hull and this Koff erdamm139 to be used for the storage of reserve coal.”140 Even a sketch drawn by pencil was attached to this part. Th is arrangement was very similar to the one described in Koudelka’s secret report one month earlier. “Th e Reichsmarineamt held on the basis of the test results that on every new ship the simple bulkhead had to be built in the outer position and the armored bulkhead in the inner position and the space between them had to use as storage of coal which could be emptied only in case of emergency.”141 Th is demonstrates that the Navy tried to use the precious information brought by Koudelka, but perhaps not hard enough. Th e Navy did not specify precisely the desirable depth of four meters of the protective system which was a mistake. However, the increase of the belt armor to 280 mm may have been a consequence of Koudelka’s report.

On 21 June, Popper presented six 20,500 ton designs. Designs A and B were new designs while the C, D, E and F were modifi cations of earlier designs. Designs A and C or B and D had the same main armament but their turret arrangements were diff erent. Design A was similar to the German battlecruiser Moltke with two wing turrets en echelon while design C was similar to the British Orion with all turrets on the centerline. Design B had two triple turrets at the ends and two wing twin turrets while design D had two triple and two twin turrets at both ends, with the twins being in superimposed position. Th e depth of the torpedo protection system was 1.2 + 0.74 m, the thickness of the torpedo bulkhead was 50 mm.142 It is unclear if this 1.94 m is the distance of the torpedo bulkhead from the side shell plating or from the inner plating of the double hull, but most probably this is the full

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Dimensions (m) Belt (mm) Main battery Secondary battery A 155×26 240 10×30.5 cm, fi ve twins 14×15 cm B 155×26 280 10×30.5 cm, two triples, two twins 14×15 cm C 151×26 280 10×30.5 cm, fi ve twins 14×15 cm D 151×26 280 10×30.5 cm, two triples, two twins 14×15 cm E 151×26 270 11×30.5 cm, three triples, one twin 14×15 cm F 151×26 240 12×30.5 cm, four triples 14×15 cm

depth of the system considering the designs with wing turrets.

On the order of the Marinesektion the MTK formed a board presided by Kontreadmiral Luzian von Ziegler on 3 July 1909 to examine the main battery of the designs of Popper. One of the board members was Kontreadmiral Karl Lanjus von Wellenburg (who was killed in August 1913 when a 30.5 cm gun exploded during proof testing). Th ey excluded at the fi rst the designs with wing turrets (A, B), as they favored the all turrets on centerline arrangement of designs C and D on the grounds that it made possible for arranging for superior torpedo protection. On strictly weight saving grounds design D was their favorite.144 Despite this, the board was in favor of using twin turrets as they had a few objections against the triple turret designs. With its larger barbette (9 m instead of 7.8 m), they considered the triple mounting to be a larger target and thus easier to hit. It was suggested that the powder smoke from fi ring the three guns would hinder the fi re control of the turret. Th ey considered the most serious objection against the triple turret was that a hit or a mechanical failure could put out of action a greater percentage of the main battery than would a similar hit on a twin turret. Th ey also feared that the triple turret, being a novel mechanism, would suff er teething problems. Th e board in its report declared that the armor penetration capability of the shorter, 45 caliber length 30.5 cm gun was suffi cient.145

Th e board’s conclusion was that design C with fi ve twin turrets all in centerline was best if the displacement limit was strict. In the case that the Navy would accept a 550 tons increase of the displacement, they recommended the slightly modifi ed design F with four triple turrets, but they still maintained their concerns over the triple turret.146

On 6 August 1909, the Navy drew up the fi nal specifi cations and sent to the MTK and the STT with the following particulars: four triple turrets, minimum thickness of belt armor 280 mm (300 mm if possible), displacement of 21,000 tons maximum, Parsons steam turbines without cruising turbines, coal fi ring boilers with oil spraying.147 Th e fi nal design of the new battleships was set. After this date only one attempt was made to make a minor change in the design, but it was soon aborted. Th e Navy wanted to double the end on fi re capacity of the 15 cm casemate guns (four guns instead of two) but when they learned that it would be possible only by decreasing the thickness of the belt armor to 230 mm, they rejected this plan.148 In the spring of 1910, Schiff bauingenieure Franz Pitzinger and Th eodor Nowotny presented their own designs based upon the 9 June specifi cations149 but at that time the detailed designs were already under way.

Works on the detailed designs started in the autumn of 1909. Th e time was short because the construction of the fi rst unit needed to be started in the spring of 1910. In the case of the Radetzky class the Navy had had a whole year to complete the detailed designs while in the case of the dreadnoughts only six months was available. Another great problem was the overwhelming design work needed for the new battleships. Everyone knew that for such a heavy armament a 22,000 ton ship would have been desirable. However, Montecuccoli had put great pressure on the Navy as he

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27 Aft 30.5 cm/45 triple turrets on Viribus Unitis

forced the twelve guns armament while still adhering to the 20,000 tons displacement limit. Th e strict displacement limit was important for Montecuccoli because he feared presenting the costs of larger and thus more expensive battleships to the politicians. Th e results of Montecuccoli’s insistence on the heavy armament and the strict displacement limit of this design were the weak hull structure and inadequate watertight bulkheads of the Tegetthoff class battleships.

In one phase of the work on the detailed designs in October-November 1909 the thickness of the belt armor was increased to 300 mm, but against Tirpitz’s advice, this was not compensated by reducing the thickness of the casemate armor (from 180 mm to 150 mm).150 Kontreadmiral Ziegler, the head of the MTK on 30 November 1909 wrote a report on the hull structure of the projected battleships. In his opinion the hull structure was too weak thanks to the extensive weight savings and he proposed two extra longitudinal frames to reinforce the hull structure. Th e extra weight of these frames were to be compensated by reducing, by his own words, the “oversized” belt armor down to 290

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