SMS Viribus Unitis SMS " Viribus Unitis " was the first Austro - Hungarian dreadnought battleship of the . Its name , meaning " " With United Forces " " , was the personal motto of Emperor Franz Joseph I . " Viribus Unitis " was ordered by the Austro - Hungarian navy in 1908 . As the first of the newly created " Tegetthoff " - class battleships , she was laid down in Stabilimento Tecnico Triestino shipyard in Trieste on 24 July 1910 . " Viribus Unitis " was launched from the shipyard on 24 June 1911 and was later formally commissioned into the Austro - Hungarian Navy on 5 December 1912 . During World War I , " Viribus Unitis " took part in the flight of the German warships and . In May 1915 , she also took part in the bombardment of the Italian port city of Ancona . " Viribus Unitis " was sunk by a limpet mine planted by frogmen of the Italian Regia Marina on 1 November 1918 . Construction and design . Construction . " Viribus Unitis " was ordered by the Austro - Hungarian Navy in 1908 . She was the first of the " Tegetthoff " - class battleships , the first ( and only ) dreadnoughts of the Austro - Hungarian Navy . The keel to " Viribus Unitis " was laid down in Stabilimento Tecnico Triestino shipyard in Trieste on 24 July 1910 . Following eleven months of construction , " Viribus Unitis " was launched on 24 June 1911 . Following her fitting out , she was commissioned into the Austro - Hungarian Navy on 5 December 1912 . Characteristics . Launched in late June 1911 , " Viribus Unitis " had an overall length of , a beam of , and a draught of at deep load . She displaced at load and at deep load . " Viribus Unitis " had four Parsons steam turbines , each of which was housed in a separate engine - room . The turbines were powered by twelve Babcock & Wilcox boilers . The turbines were designed to produce a total of , which was theoretically enough to attain her designed speed of , but no figures from her speed trials are known to exist . She carried of coal , and an additional of fuel oil that was to be sprayed on the coal to increase its burn rate . At full capacity , she could steam for at a speed of . " Viribus Unitis " mounted twelve / 45 - caliber K 10 guns in four triple turrets . Her secondary armament consisted of twelve / 50 K 10 guns mounted in casemate s amidships . Twelve / 50 K 10 guns were mounted on open pivots on the upper deck above the casemates . Three more 66 - mm K 10 guns were mounted on the upper turrets for anti - aircraft duties . Four submerged torpedo tube s were fitted , one each in the bow , stern and on each broadside ; twelve torpedoes were carried . Service history . Archduke Franz Ferdinand ' s visit to Sarajevo . Archduke Franz Ferdinand of Austria traveled aboard the " Viribus Unitis " in late June 1914 en route to Bosnia to observe military maneuvers . On 25 June , he boarded the ship in Trieste Harbor and travelled to the mouth of the Narenta River , where he transferred to another vessel . On 30 June , two days after Ferdinand and his wife were killed by Gavrilo Princip in the Bosnian city of Sarajevo , " Viribus Unitis " transported their bodies back to Trieste . World War I . Prior to the war , " Viribus Unitis " was assigned to the 1st Battleship Division of Austro - Hungarian Navy . During World War I , the battleship saw limited service due to the Otranto Barrage which prohibited Austro - Hungarian battleships from leaving the Adriatic sea . As a result , she hardly ever left Pola . " Viribus Unitis " , along with her sister ships , and the remainder of the Austro - Hungarian Navy , was mobilized on the eve of World War I to support the flight of and . The two German ships were stationed in the Mediterranean and were attempting to break out of the strait of Messina , which was surrounded by British troops and vessels and make their way to Turkey . After the Germans successfully broke out of Messina , the navy was recalled . The fleet had by that time advanced as far south as Brindisi in south eastern Italy . " Viribus Unitis " also participated in the bombardment of the Italian city of Ancona in May 1915 . Following these operations " Viribus Unitis " remained in Pola for most of the remainder of the war . Her tenure in Pola was livened up by a visit from the new Emperor Karl I on 15 December 1916 and another by Kaiser Wilhelm II on 12 December 1917 during his inspection of the German submarine base there . The Italians conducted no less than eighty air raids on Pola between 1915 and 1917 which undoubtedly kept the crews of her anti - aircraft gun busy . The Otranto Raid . By 1918 , the new commander of the Austrian fleet , Konteradmiral Miklós Horthy , decided to conduct another attack on the Otranto Barrage to allow more German and Austro - Hungarian U - boats to safely get through the heavily defended strait . During the night of 8 June , Horthy left the naval base of Pola with the " Viribus Unitis " and the " Prinz Eugen " . The other two dreadnoughts , and " Tegetthoff " , along with one destroyer and six torpedo boat s departed Pola on 9 June . At about 3 : 15 on the morning of 10 June , two Italian MAS boats , " MAS 15 " and " MAS 21 " , spotted the Austrian fleet . The MAS platoon was commanded by " Capitano di fregata " Luigi Rizzo while the individual boats were commanded by " Capo timoniere " Armando Gori and " Guardiamarina di complemento " Giuseppe Aonzo respectively . Both boats successfully penetrated the escort screen and split to engage each of the dreadnoughts . " MAS 21 " attacked " Tegetthoff " , but her torpedoes failed . " MAS 15 " managed to hit the " Szent István " with her torpedoes at about 3 : 25 am . Both boats were then chased away from the scene by the Austrian escort vessels . Despite attempts to take the crippled " Szent István " into tow by the " Tegetthoff " , the ship continued to sink and the attempt was abandoned . A few minutes after 6 : 00 am the " Szent István " sank . Admiral Horthy , commander of the proposed attack , soon canceled the attack because he thought that the Italians had discovered his plan and ordered the ships to return to Pola . On the contrary , the Italians did not even discover that the Austrian dreadnoughts had departed Pola until later on 10 June when aerial reconnaissance photos revealed that they were no longer there . This was the last military operation that the " Viribus Unitis " was to take part in and she spent the rest of her career at port in Pola . Sinking . After it was clear that Austria - Hungary had lost World War I , the Austrian government decided to give the ship , along with much of the fleet , to the newly formed State of Slovenes , Croats and Serbs . This move would have avoided handing the fleet to the Allies , since the new state had declared neutrality . Following the transfer of the " Viribus Unitis " to the State of Slovenes , Croats and Serbs , she was renamed the " Jugoslavija " . Ignoring this move , on 1 November 1918 , two men of the Regia Marina , Raffaele Paolucci and Raffaele Rossetti , rode a primitive manned torpedo ( nicknamed the " Mignatta " or " leech " ) into the Austro - Hungarian naval base at Pola . Using limpet mine s , they then sank the " Viribus Unitis " as well as the freighter " Wien " . Traveling down the rows of Austrian battleships , the two men encountered the " Viribus Unitis " at around 4 : 40 am . Rossetti placed one canister of TNT on the hull of the battleship , timed to explode at 6 : 30 am . He then flooded the second canister , sinking it on the harbor floor close to the ship . This second canister exploded close to the Austrian freighter " Wien " , resulting in her sinking . The men had no breathing sets , and therefore had to keep their heads above water . They were discovered and taken prisoner just after placing the explosives under the battleship ' s hull . The Italians did not know that the Austrian government had handed over the " Viribus Unitis " along with most of the Austro - Hungarian fleet to the newly created State of Slovenes , Croats and Serbs . The two - man team were captured and taken aboard " Viribus Unitis " , where they informed the new captain of the battleship what they had done but did not reveal the exact position of the explosives . Admiral Vuković then arranged for the two prisoners to be taken safely to the sister ship , and ordered the evacuation of the ship . The explosion did not happen at 6 : 30 as predicted and Vuković returned to the ship with many sailors ( believing mistakenly that the Italians had lied ) . He therefore remained on his ship and went down with her and 300 – 400 of her crew when the mines exploded shortly afterwards at 6 : 44 . Following the explosion , the battleship sank in 15 minutes . The two Italian crew were interned for a few days until the end of the war and were honored by the Kingdom of Italy with the Gold Medal of Military Valor . Commemorations . SMS " Viribus Unitis " was selected as the main motif of a high value collectors ' coin : the Austrian SMS " Viribus Unitis " commemorative coin , minted on 13 September 2006 . The obverse side shows the flagship " Viribus Unitis " as seen from the deck of an accompanying ship in the fleet . Two other ships of an older class can be seen in the background . The reverse of the coin is a tribute to the old Austro - Hungarian Imperial Navy , showing the SMS " Viribus Unitis " from a front angle . A naval biplane circles overhead and a submarine surfaces in the foreground . The coin commemorates not only the ship " Viribus Unitis " , but also the three main arms of the Austro - Hungarian Navy in the First World War . The coin was the last of the series " Austria on the High Seas " . References . Explanatory notes Citations