SMS Orjen was one of six s built for the (Austro-Hungarian Navy) shortly before the First World War. Completed in 1914, she helped to sink an Italian destroyer during the action off Vieste in May 1915 after Italy declared war on Austria-Hungary. Two months later the ship participated in an unsuccessful attempt to recapture a small island in the central Adriatic Sea from the Italians. In November and early December Orjen was one of the ships conducting raids off the Albanian coast to interdict the supply lines between Italy and Albania, although she did not participate in the First Battle of Durazzo in late December. Orjen participated in several raids on the Otranto Barrage in 1916–1917 with limited success. She was transferred to Italy in 1920 in accordance with the peace treaties ending the war and renamed Pola. She mostly served as a training ship or in Italian North Africa when she was not in reserve from 1924 to 1928. Renamed Zenson in 1931, the ship was scrapped in 1937.
Design and description
The Tátra-class destroyers were faster, more powerfully armed and more than twice as large as the preceding . The ships had an overall length of , a beam of , and a maximum draft of . They displaced at normal load and at deep load. The ships had a complement of 105 officers and enlisted men.
The Tátras were powered by two AEG-Curtiss steam turbine sets, each driving a single propeller shaft using steam provided by six Yarrow boilers. Four of the boilers were oil-fired while the remaining pair used coal. The turbines, designed to produce , were intended to give the ships a speed of . The ships carried enough oil and coal to give them a range of at .
The main armament of the Tátra-class destroyers consisted of two 50-caliber Škoda Works K10 guns, one each fore and aft of the superstructure in single, unprotected mounts. Their secondary armament consisted of six 45-caliber guns, two of which were on anti-aircraft mountings. They were also equipped with four torpedo tubes in two twin rotating mountings amidships.
Construction and career
Orjen was laid down by Ganz-Danubius at their shipyard in Porto Ré in the Kingdom of Croatia-Slavonia of the Austro-Hungarian Empire on 4 September 1912, launched on 26 August 1913 and completed on 11 August 1914. The Tátra-class ships did not play a significant role in the minor raids and skirmishing in the Adriatic in 1914 and early 1915 between the Entente Cordiale and the Central Powers. From 9 to 24 December, Orjen had her propeller shaft bearings replaced in Pola.
Action off Vieste
The Kingdom of Italy signed a secret treaty in London in late April 1915 breaking its alliance with the German Empire and Austro-Hungary and promising to declare war on the Central Powers within a month. Austro-Hungarian intelligence discovered this and Admiral Anton Haus, commander of the Austro-Hungarian Navy, planned a massive surprise attack on Italian ports and facilities on the northern Adriatic coast, outside of interception range of the modern ships of the (Royal Italian Navy) stationed at Taranto. To warn of any Italian warships able to interfere with the bombardments, Haus prepositioned three groups of destroyers, each led by a scout cruiser. Placed in the central Adriatic between the island of Pelagosa and the Italian coast, four days prior to the Italian declaration of war on 23 May, were four Tátra-class destroyers, including Orjen, and the cruiser . Around midnight on the night of 23/24 May, Haus ordered the reconnaissance groups to move west and attack Italian coastal targets. About an hour later the four Tátras encountered a pair of Italian s, and , but in the darkness they were believed by the Italians to be friendly ships.