Austria's Dreadnoughts: Effective Or Expensive?

The Austro-Hungarian Navy's Tegetthoff-class battleships were the country's only class of dreadnoughts. The four ships in the class—SMS Viribus Unitis, SMS Tegetthoff, SMS Prinz Eugen, and SMS Szent István—were commissioned between 1912 and 1915, with the first three entering service before the outbreak of World War I.

The Tegetthoff-class battleships were poorly designed and built, suffering significant losses during the war. They were likely the least successful of their type, with design flaws that included poor underwater protection and a high centre of gravity. However, they were well-armed for their size, carrying twelve 30.5 cm (12-inch) main guns.

Despite their flaws, the Tegetthoff-class dreadnoughts have an intriguing history, from their conception amidst corruption and political scheming to their involvement in significant naval operations during the war, such as the Bombardment of Ancona and the Battle of Antivari.

Design and construction

The Tegetthoff-class battleships were the only group of dreadnought battleships constructed by Austria-Hungary. The Austro-Hungarian Navy needed to update its fleet following the construction of HMS Dreadnought. After the announcement in 1908 of the start of construction for the first dreadnought of the Regia Marina (the Italian Navy), the Dante Alighieri, the Austro-Hungarian Navy formally ordered the construction of a series of four dreadnought battleships.

The first three battleships were constructed in the Stabilimento Tecnico Triestino shipyard in Trieste, while the fourth battleship, Szent István was constructed at the Danubius shipyard at Fiume. All of the battleships were constructed between 1910 and 1915. Two of the Tegetthoff-class battleships were commissioned less than two years prior to the beginning of World War I, while Prinz Eugen was commissioned the same month as the assassination of Archduke Franz Ferdinand. The last battleship of the class, Szent István, was commissioned during the war in November 1915.

The design of the Tegetthoff-class battleships was by naval architect Siegfried Popper. They had an overall length of 152 meters (498 ft 8 in), with a beam of 27.90 meters (91 ft 6 in) and a draught of 8.70 meters (28 ft 7 in) at deep load. They were designed to displace 20,000 metric tons (19,684 long tons) at load, but at full combat load they displaced 21,689 metric tons (21,346 long tons). The hull was built with a double bottom, 1.22 meters (4 ft) deep, with a reinforced inner bottom that consisted of two layers of 25-millimetre (1 in) plates. This design was intended by Popper to protect the battleships from naval mines, although it ultimately failed both Szent István and Viribus Unitis, the former being sunk by a torpedo in June 1918 and the latter by a mine in November of that same year. The Tegetthoff class also featured two 2.74-meter (9 ft) Barr and Stroud optical rangefinder posts on both the starboard and port sides for the secondary guns of each ship. These rangefinders were equipped with an armoured cupola, which housed an 8-millimetre (0.31 in) Schwarzlose M.07/12 anti-aircraft machine gun.

Szent István had a few external variations from the other ships of her class. These differences included a platform built around the fore funnel which extended from the bridge of the ship to the after funnel upon which several searchlights were installed. A further distinguishing feature was the modified ventilator trunk in front of the mainmast. The rangefinders on Szent István had an armoured stand which turned 90° to the right of those on the other three ships. This was done in order to present a smaller target for the ship's broadside. Perhaps the most notable distinguishing characteristic of Szent István was that she was the only ship of her class not to be fitted with torpedo nets. The other three ships of the Tegetthoff class had their torpedo nets removed in June 1917. The Tegetthoff-class ships were manned by a crew of 1,087 officers and men.

Differences between the three battleships constructed in Trieste and the one in Fiume were most apparent when examining each ship's propulsion. Szent István differed from the other ships in that she possessed two propellers and two larger Parsons steam turbines, while the propulsion of Viribus Unitis, Tegetthoff, and Prinz Eugen each had four smaller Siemens turbines and four propellers. These turbines were housed in a separate engine room and with the exception of SMS Szent István, they were powered by twelve Yarrow boilers. The more modern new type of Babcock & Wilcox boilers of Szent István were 48 tonnes heavier than the older type Yarrow boilers installed on the sister ships; however, they were more efficient than the old boilers. The new Babcock & Wilcox boilers had a huge advantage of being able to maintain top speed for up to eight hours, compared with only two hours on their sister ships. They were designed to produce a total of 26,400 or 27,000 shaft horsepower (19,686 or 20,134 kW), which was theoretically enough to attain a maximum designed speed of 20 knots (37 km/h; 23 mph). While it was reported during the speed trials of Tegetthoff that she attained a top speed of 19.75 knots (36.58 km/h; 22.73 mph), the actual top speed of the Tegetthoff-class ships is unknown as the sea trial data and records for each ship were lost after the war. Each ship also carried 1,844.5 metric tons (1,815.4 long tons) of coal, and an additional 267.2 metric tons (263 long tons) of fuel oil that was to be sprayed on the coal to

Armament and armour

The Austro-Hungarian Navy's Tegetthoff-class battleships were the country's only dreadnoughts. The class was made up of four battleships: SMS Viribus Unitis, Tegetthoff, SMS Prinz Eugen, and SMS Szent István. They were constructed between 1910 and 1915, with the first two being commissioned in 1912 and 1913, respectively, and Prinz Eugen in July 1914, the same month as the assassination of Archduke Franz Ferdinand. The last battleship of the class, Szent István, was commissioned during World War I in November 1915.

The Tegetthoff-class battleships were designed by naval architect Siegfried Popper. They had an overall length of 152 metres, with a beam of 27.90 metres and a draught of 8.70 metres at deep load. They were designed to displace 20,000 metric tons at load, but at full combat load, they displaced 21,689 metric tons. The Tegetthoffs were armed with twelve 45-calibre 30.5-centimetre Škoda K10 guns mounted in four triple turrets. The choice of implementing triple turrets was to ensure the ships had a more compact design and smaller displacement to conform to Austro-Hungarian naval doctrine and budget constraints, and to counter the implementation of triple turrets on the Italian Dante Alighieri. The Tegetthoffs carried a secondary armament that consisted of a dozen 50-calibre 15-centimetre Škoda K10 guns mounted in casemates amidships. Additionally, they had eighteen 50-calibre 7-centimetre Škoda K10 guns mounted on open pivot mounts on the upper deck, above the casemates. Three more 7-centimetre Škoda K10 guns were mounted on the upper turrets for anti-aircraft duties. Each ship also had two 7-centimetre Škoda G. L/18 landing guns and two 47-millimetre Škoda SFK L/44 S guns for use against small and fast vessels such as torpedo boats and submarines. Each ship was also fitted with four 533-millimetre submerged torpedo tubes, one each in the bow, the stern, and each side. Each ship usually carried twelve torpedoes.

The Tegetthoff-class ships were protected at the waterline with an armour belt that measured 280 millimetres thick in the central citadel, where the most important parts of the ship were located. This armour belt was located between the midpoints of the fore and aft barbettes, and thinned to 150 millimetres further towards the bow and stern, but did not reach either. It was continued to the bow by a small patch of 110–130-millimetre armour. The upper armour belt had a maximum thickness of 180 millimetres, but it thinned to 110 millimetres from the forward barbette all the way to the bow. The casemate armour was also 180 millimetres thick. The sides of the main gun turrets, barbettes, and main conning tower were protected by 280 millimetres of armour, except for the turret and conning tower roofs, which were 60 to 150 millimetres thick. The thickness of the decks ranged from 30 to 48 millimetres in two layers. The underwater protection system consisted of the extension of the double bottom upwards to the lower edge of the waterline armour belt, with a thin 10-millimetre plate acting as the outermost bulkhead. It was backed by a torpedo bulkhead that consisted of two 25-millimetre plates. The total thickness of this system was only 1.60 metres, which made it incapable of containing a torpedo warhead detonation or mine explosion without rupturing.

The Tegetthoff-class battleships were over-armed with twelve 305-millimetre guns for their 20,000-ton displacement. In comparison, the British pre-1914 battleships 'Barham', 'Royal Oak', 'Queen Elizabeth', and 'Valiant' were all sunk by torpedoes in World War II, yet no one seems to claim that the British ships were design failures. No pre-1914 battleships of any nation, with the possible exception of those of the German navy, had adequate underwater protection against mines and torpedoes.

The Tegetthoff-class battleships were also inferior to the more modern Dreadnought type battleships, with their "all big gun" armament and turbine propulsion. The Tegetthoffs were among the last semi-dreadnought battleships to be built. Popper pointed out that the maximum conceivable displacement possible until the Trieste and Fiume shipyards could be enlarged was about 16,000 tons. On that weight, he could mount no more than eight heavy guns with barely adequate protection and reduced speed. Instead, it was decided to install four 30.5-centimetre and eight 24-centimetre guns, all in twin turrets.

Propulsion and speed

The Szent István's propulsion system was designed to produce a total of 26,400 or 27,000 shaft horsepower, theoretically enough to attain a maximum speed of 20 knots. However, the actual top speed of the Tegetthoff-class ships is unknown, as the sea trial data and records for each ship were lost after World War I. During speed trials for the SMS Tegetthoff, it was reported that the ship attained a top speed of 19.75 knots. Each ship carried 1,844.5 metric tons of coal and an additional 267.2 metric tons of fuel oil, giving them a range of 4,200 nautical miles at a speed of 10 knots.

Operational history

The Tegetthoff-class battleships were the only group of dreadnought battleships constructed by Austria-Hungary. The Austro-Hungarian Navy needed to update its fleet following the construction of HMS Dreadnought. After the announcement in 1908 of the start of construction for the first dreadnought of the Regia Marina (the Italian Navy), the Austro-Hungarian Navy formally ordered the construction of a series of four dreadnought battleships. The first three battleships were constructed in the Stabilimento Tecnico Triestino shipyard in Trieste, while the fourth battleship, Szent István, was constructed at the Danubius shipyard at Fiume. All of the battleships were constructed between 1910 and 1915.

Two of the Tegetthoff-class battleships were commissioned less than two years before the beginning of World War I, while Prinz Eugen was commissioned the same month as the assassination of Archduke Franz Ferdinand. The last battleship of the class, Szent István, was commissioned during the war in November 1915. Prior to the war, the battleships in commission were assigned to the 1st Battleship Division of the 1st Battle Squadron of the Austro-Hungarian Navy. During the war, the ships had limited service due to the Otranto Barrage, which prevented the battleships from leaving the Adriatic Sea. As a result, they rarely left Pola. However, three of the battleships participated in the flight of the German battlecruiser SMS Goeben and light cruiser SMS Breslau in 1914, and in the bombardment of the Italian city of Ancona in May 1915. (Szent István was still under construction.) Following these operations and the completion of the Szent István, the Tegetthoff-class battleships remained in port for the remainder of the war.

The final operation for the Tegetthoff-class ships was an attempt to break through the Otranto Barrage in June 1918. During the journey to the Strait of Otranto, the battleship Szent István was torpedoed and sunk on 10 June 1918, resulting in the operation being called off. Viribus Unitis was also sunk prior to the end of the war on 1 November 1918 when a team of Italian frogmen sank the battleship with mines while she was moored at port in Pula. Following Austria-Hungary's defeat in World War I, the remaining two battleships of the class were handed over to the Allies, with the Tegetthoff being given to Italy and scrapped in 1924 and Prinz Eugen being handed over to France and sunk as a target ship in 1922.

Legacy

The Tegetthoff-class battleships were the only group of dreadnought battleships constructed by Austria-Hungary. They were the first dreadnoughts in the world with triple turrets, a source of pride for the Austro-Hungarian Navy. The class was composed of four battleships: SMS Viribus Unitis, SMS Tegetthoff, SMS Prinz Eugen, and SMS Szent István.

The legacy of the Tegetthoff-class battleships is a mixed bag. On the one hand, they were poorly designed and built, suffering significant losses during World War I. They had design flaws, such as inadequate underwater protection, that made them vulnerable to torpedoes and mines. On the other hand, they were also over-armed for their size and had good armour protection. They were described as excellent ships and some of the most powerful in the region.

The Tegetthoff-class battleships were commissioned just before World War I, with the first two, Viribus Unitis and Tegetthoff, entering service in 1912 and 1913, respectively. Prinz Eugen followed in July 1914, the same month as the assassination of Archduke Franz Ferdinand. The last battleship of the class, Szent István, was commissioned during the war in November 1915.

During the war, the battleships had limited service due to the Otranto Barrage, which prevented them from leaving the Adriatic Sea. They rarely left their base at Pola and mostly defended Austria-Hungary's coastline. However, they did participate in the flight of the German battlecruiser SMS Goeben and light cruiser SMS Breslau in 1914 and the bombardment of the Italian city of Ancona in May 1915.

The final operation for the Tegetthoff-class ships was an attempt to break through the Otranto Barrage in June 1918. During this mission, the battleship Szent István was torpedoed and sunk by an Italian motor torpedo boat, resulting in the operation being called off. Viribus Unitis was also sunk before the end of the war in November 1918 when Italian frogmen mined the battleship while it was moored at port in Pula.

Following Austria-Hungary's defeat in World War I, the remaining two battleships of the class, Tegetthoff and Prinz Eugen, were handed over to the Allies. Tegetthoff was given to Italy and scrapped between 1924 and 1925, while Prinz Eugen was ceded to France and sunk as a target ship in 1922.

The Tegetthoff-class battleships remain a fascinating chapter in the history of naval warfare, with their unique design, powerful armament, and the challenges they faced during World War I. They continue to be a subject of interest for military historians and enthusiasts alike.

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