Ersatz Zenta-class cruiser

The Ersatz Zenta-class was a class of three planned light cruisers of the Austro-Hungarian Navy designed in the mid-1910s as part of a naval expansion program passed during a period of rising tensions in Europe. Several designs were proposed, including options for a so-called "yacht cruiser" that was to have been used by Archduke Franz Ferdinand, the heir to the Austro-Hungarian throne. The design that was ultimately selected called for ships that were capable of speeds of at least 30 knots (56 km/h; 35 mph), with an armament of fourteen 12-centimeter (4.7 in) guns and a thin armored belt that was 20 millimeters (0.79 in) thick.

The ships, only ever given the contract names "K", "L", and "M", were scheduled to be laid down beginning in July 1914. The assassination of Archduke Franz Ferdinand the month before and the resulting July Crisis, which culminated in the start of World War I on 28 July, led the navy to cancel all new ship construction projects. Work on a revised version of the design began in December 1915, but shortages of material and a lack of skilled shipyard workers meant that the new design would be completed on paper only.

Development

The Italo-Turkish War of 1911–1912 and the Balkan Wars of 1912–1913 significantly increased tensions in Europe, which saw the dismemberment of large swaths of the Ottoman Empire. These conflicts provided the background for a major naval expansion program in Austria-Hungary, which received broad support in the Austrian and Hungarian parliaments. Admiral Anton Haus, then the Marinekommandant (Navy Commander) used the growing risk of war with Austria-Hungary's nominal ally, Italy, to push his construction program.^[1] As part of its construction program, the navy projected to build three cruisers, and adopted a secret construction schedule on 12 January 1914, which called for the first vessel to be laid down on 1 July 1914, followed by the other two on 1 July 1915.^[2] The first ship was projected to be completed by 31 December 1917, with the second and third following on 31 December 1918.^[3]

Preliminary design work on what became the Ersatz Zenta class began in May 1913, before the budgetary debate had begun. The Marinetechnische Komitee (MTK—Naval Technical Committee) issued a series of requirements for the new cruiser: displacement would be in the range of 4,500 to 4,800 metric tons (4,400 to 4,700 long tons; 5,000 to 5,300 short tons), speed would be 29.5 to 30 knots (54.6 to 55.6 km/h; 33.9 to 34.5 mph) from steam turbines, with a radius of action of 1,200 nautical miles (2,200 km; 1,400 mi) at a speed of 24 knots (44 km/h; 28 mph). The ship would carry no armor protection, and the armament would consist of either twelve 12-centimeter (4.7 in) 45-caliber (cal.) guns and two 9 cm (3.5 in) anti-aircraft guns, or fourteen of the 12 cm guns and four 45 cm (18 in) torpedo tubes in single or double mounts.^[1]

During the design process, Archduke Franz Ferdinand of Austria, the heir to the Austro-Hungarian throne, requested that one of the new cruisers be built as a "yacht cruiser". The designers considered two options to accommodate Ferdinand's request, the first with a deck house on the stern in place of some of the guns; in the event of war, the deck house could be removed and the guns installed, and the second wherein the ship would not be readily converted and would only be used for auxiliary roles during a conflict. In either case, the maximum speed for the so-called "yacht cruiser" was to be 24 knots (44 km/h; 28 mph), with no armor protection, and it was to resemble the other two ships as closely as possible.^[4]

On 12 September 1913, the navy began the design competition, soliciting offers from several different shipyards. The designer of the winning bid was to receive a prize of 2,450 krone and the runner-up would receive 1,750 krone. Franz Pitzinger, the chief constructor of the Austro-Hungarian navy, was occupied with the design of the Ersatz Monarch-class battleships, allowing one of the private firms an opportunity to design the new class of cruisers. Two naval engineers, Silvius Morin of the MTK and Johann Fiala, who oversaw the construction of the cruiser Admiral Spaun at the Pola Naval Arsenal, submitted the two most serious proposals. Fiala submitted to variants, Ia and IIb, along with a third for the "yacht cruiser" that was considered separately during the design competition. His third design, Ic, was identical in dimensions to the other two proposals, though it incorporated an armored belt of 60-millimeter (2.4 in) Krupp cemented steel.^[5] Though busy with the Ersatz Monarch project, Pitzinger nevertheless submitted a design by the deadline.^[6]

Proposals

Design selection and approval

On 14 April 1914, the navy ruled out Morin's design. Fiala's Ib design was the version chosen, though the navy requested several alterations. These included lengthening the forecastle by 16 frames to increase space for crew berths and the addition of a 20 mm (0.79 in) thick armored belt, which would extend from 2 m (6 ft 7 in) above the waterline and 1.2 m (3 ft 11 in) below the line. The changes caused the displacement to rise by 154.3 t (151.9 long tons; 170.1 short tons). A four shaft arrangement was also proposed as a possibility.^[3] The changes requested by the navy evidenced an evolution in Austro-Hungarian cruiser designs away from the unarmored scout cruisers of the earlier Admiral Spaun and Novara types toward modern light cruisers suited to fleet operations.^[2]

On 16 May, the navy informed the shipbuilding firms Stabilimento Tecnico Triestino (STT), Ganz—Danubius, CNT Monfalcone, and San Rocco AG to submit tenders to build the ships, with a deadline of 5 July. At the same time, Fiala issued a request for a 40,000 shp (30,000 kW) propulsion system to STT, Ganz—Danubius, and Breitfeld & Danek. On 28 May, the navy secured approval for its naval construction program, which called for four battleships, three cruisers, and six destroyers. On 2 August, days after the outbreak of World War I, the navy awarded Ganz—Danubius with the contract to build the three cruisers. It had settled on a two-shaft arrangement with AEG-Curtis turbines license-built by Ganz—Danubius.^[3]

The "yacht cruiser" project was handled separately by the navy; Morin's design was again ruled out, now because he had focused his design too much on the yacht aspect of the vessel, neglecting its military qualities. Again, the navy chose Fiala's proposal, named IIb, as the basis for the "yacht cruiser", citing its heavier armament and higher speed, compared to Morin's vessel. But no final design had been approved by the time Franz Ferdinand was assassinated in Sarajevo on 28 June 1914; with the death of the man who had requested the "yacht cruiser", the navy no longer had a reason to pursue the project.^[8]

Characteristics

As adopted, the Ersatz Zenta-class ships were to have been 151.2 m (496 ft) long at the waterline and 153.1 m (502 ft) long overall. Their beam was to have been 13.7 m (45 ft). The class had a design displacement of 4,950 t (4,870 long tons; 5,460 short tons), with a full load displacement of 5,611 t (5,522 long tons; 6,185 short tons); at deep load, their draft was to be 6.4 m (21 ft).^[2][9]

The ships were to be powered by two AEG-Curtis turbines, each rated at 20,000 shp (15,000 kW), meeting the required 40,000 shp output. Steam was provided by sixteen Yarrow boilers, eight of which were to burn coal and the other eight to burn fuel oil.^[10] Top speed was to have been 30.1 knots (55.7 km/h; 34.6 mph). Fuel storage capacity and thus cruising range are unknown.^[2][9]

The ships retained the fourteen 12 cm 45-cal. guns of Fiala's design, and received a 47 mm (1.9 in) 44-cal. gun and a 66 mm (2.6 in) 18-cal. landing gun in addition.^[2][9] The 12 cm guns had reached the prototype stage only by the outbreak of World War I saw the ships' cancellation, so no performance data exists. A longer-barreled 50-cal. version was also prepared for possible use aboard the Ersatz Zenta class, but it too did not see completion.^[11] They were also to carry a pair of 533 mm (21.0 in) torpedo tubes in deck-mounted launchers located amidships. Armor protection consisted of the 20 mm belt, along with a 38 mm (1.5 in) thick armor deck.^[2][9]

Construction and cancellation

With the outbreak of World War I on 28 July 1914, construction never began on the three cruisers, referred to in the budget as cruisers "K", "L", and M".^[2] Indeed, the navy refused to use part of the 426.8 million krone war appropriations to fund construction of the vessels, preferring to await the end of what was expected to be a short war, and then use the additional wartime funds to build improved ships. The navy mistakenly assumed no new projects could be completed before the war would be over, and any wartime experience would necessarily have to be incorporated in any future design.^[8][12] Instead, in late 1914, a scale model of the design was taken to the Tiergarten in Berlin, where the Königlichen Versuchsanstalt für Wasserbau und Schiffbau (Royal Research Institute for Hydraulic Engineering and Shipbuilding) had testing facilities, since the Austro-Hungarian Navy had no such capability.^[8]

While Fiala remained at STT, he continued to refine the design. On 14 May 1915, nine days before Italy declared war on Austria-Hungary, Fiala was recalled to the MTK. He continued to independently work on the cruiser project as late as 14 December that year. On 25 December, he was officially ordered to prepare a revised design with the following characteristics: armament was to be increased to two 19 cm (7.5 in) 45-cal. guns in a twin gun turret, supported by six to eight 15 cm (5.9 in) 50-cal. guns in single mounts and two 9 cm (3.5 in) 45-cal. anti-aircraft guns; the 533 mm torpedo tubes would be retained. Speed was to be 29 to 30 knots, with a cruising radius sufficient to allow operations in the Mediterranean Sea. The new ships would also incorporate a 150 mm (5.9 in) thick armored belt.^[8]

The new project was simply a design study only, since the majority of the shipyard workers had already been drafted into the Austro-Hungarian Army and material shortages prevented any actual work from being done anyway.^[8] It nevertheless represented the lessons learned from the first year of the war, including the fact that the 12 cm guns used on earlier Austro-Hungarian cruisers was wholly insufficient, as exemplified by the loss of the German cruiser Emden to the 6-inch (150 mm) gun armed HMAS Sydney in 1914. The lack of shipyard workers was itself a result of the navy's decision at the start of the war to stop new construction; since the shipyards no longer needed large work forces, those men could be used in the army.^[13]

Citations

References

• Friedman, Norman (2011). Naval Weapons of World War I. Annapolis: Naval Institute Press. ISBN 978-1-84832-100-7. 
• Gardiner, Robert; Gray, Randal (1984). Conway's All the World's Fighting Ships: 1906–1921. Annapolis, MD: Naval Institute Press. ISBN 0-85177-245-5. 
• Greger, René (1976). Austro-Hungarian Warships of World War I. London: Allan. ISBN 9780711006232. 
• Sieche, Erwin (2002). Kreuzer und Kreuzerprojekte der k.u.k. Kriegsmarine 1889–1918 [Cruisers and Cruiser Projects of the Austro-Hungarian Navy, 1889–1918] (in German). Hamburg. ISBN 3-8132-0766-8. 
• Sokol, Eugene (1978). "Austria-Hungary's Naval Building Projects, 1914–1918". Warship International. International Naval Research Organization. 3: 185–199.