Editing Tegetthoff-class battleship (section)

=== World War I ===
==== Outbreak of war ====
{{see also|Pursuit of Goeben and Breslau}}
[[File:SMS Tegetthoff anchored.png|thumb|300px|''Tegetthoff'', the namesake ship of her class|alt=A large battleship sits still in the water near land. Several small boats can be seen in the foreground while a large hill appears behind the battleship in the background.|right]]
Events unfolded rapidly in the ensuing days. On 30 July 1914 Russia declared full [[mobilization]] in response to Austria-Hungary's declaration of war on Serbia. Austria-Hungary declared full mobilization the next day. On 1 August both Germany and France ordered full mobilization and Germany declared war on Russia in support of Austria-Hungary. While relations between Austria-Hungary and Italy had improved greatly in the two years following the 1912 renewal of the [[Triple Alliance (1882)|Triple Alliance]],{{sfn|Sondhaus|1994|pp=232–234}} increased Austro-Hungarian naval spending, political disputes over influence in [[Principality of Albania|Albania]], and Italian concerns over the potential annexation of land in the [[Kingdom of Montenegro]] caused the relationship between the two allies to falter in the months leading up to the war.{{sfn|Sondhaus|1994|pp=245–246}} Italy's 1 August declaration of neutrality in the war dashed Austro-Hungarian hopes to use the ships of the ''Tegetthoff'' class in major combat operations in the Mediterranean, as the navy had been relying upon coal stored in Italian ports to operate in conjunction with the ''Regia Marina''. By 4 August Germany had already occupied [[Luxembourg]] and invaded [[Belgium]] after declaring war on France, and the United Kingdom had declared war on Germany in support of Belgian neutrality.{{sfn|Sondhaus|1994|p=246}}

The assistance of the Austro-Hungarian fleet was called upon by the German [[Mediterranean Division]], which consisted of the [[battlecruiser]] {{SMS|Goeben||2}} and ''Breslau''.{{sfn|Halpern|1995|p=53}} The German ships were attempting to break out of [[Messina]], where they had been taking on coal prior to the outbreak of war. By the first week of August, British ships had begun to assemble off Messina in an attempt to trap the Germans. While Austria-Hungary had not yet fully mobilized its fleet, a force was assembled to assist the German ships. This consisted of the three ''Radetzky''s and the three ''Tegetthoff''s, along with the armored cruiser {{SMS|Sankt Georg||2}}, ''Admiral Spaun'', six destroyers, and 13 torpedo boats.{{sfn|Sondhaus|1994|pp=248–249}} The Austro-Hungarian high command, wary of instigating war with Great Britain, ordered the fleet to avoid the British ships and to only support the Germans openly while they were in Austro-Hungarian waters. On 7 August, when the Germans [[Pursuit of Goeben and Breslau|broke out of Messina]], the Austro-Hungarian fleet had begun to sail for [[Brindisi]] to link up with the Germans and escort their ships to a friendly port in Austria-Hungary. However, the German movement toward the mouth of the Adriatic had been a diversion to throw the British and French off their pursuit, and the German ships instead rounded the southern tip of Greece and made their way to the [[Dardanelles]], where they would eventually be sold to the [[Ottoman Empire]]. Rather than follow the German ships towards the [[Black Sea]], the Austrian fleet returned to Pola.{{sfn|Halpern|1995|p=54}}{{sfn|Sondhaus|1994|pp=249, 258–259}}

==== 1914–1915 ====
{{main|Adriatic Campaign of World War I}}
[[File:SMS Szent Istvan 1915.png|thumb|left|300px|''Szent István'' in Pola on 15 December 1915|alt=A large battleship steams through a harbor. Large clouds of smoke can be seen coming from the ship's funnels while a smaller vessel is sailing in the foreground. Hills and the coastline can be seen in the background.]]

Following France and Britain's declarations of war on Austria-Hungary on 11 and 12 August respectively, the French Admiral [[Augustin Boué de Lapeyrère]] was issued orders to close off Austro-Hungarian shipping at the entrance to the Adriatic Sea and to engage any Austro-Hungarian ships his Anglo-French fleet came across. Lapeyrère chose to attack the Austro-Hungarian ships blockading Montenegro. The ensuing [[Battle of Antivari]] ended Austria-Hungary's blockade, and effectively placed the entrance of the Adriatic Sea firmly in the hands of Britain and France.{{sfn|Koburger|2001|pp=33, 35}}{{sfn|Sondhaus|1994|p=251}}

After the breakout of ''Goeben'' and ''Breslau'', the ships of the ''Tegetthoff'' class saw very little action, spending much of their time in their base at Pola. The navy's general inactivity was partly caused by a fear of mines in the Adriatic.{{sfn|Halpern|1995|p=144}} Other factors contributed to the lack of naval activity among the ships of the ''Tegetthoff'' class in the first year of the war. Haus was fearful that direct confrontation with the French Navy, even if it should be successful, would weaken the Austro-Hungarian Navy to the point that Italy would have a free hand in the Adriatic.{{sfn|Sondhaus|1994|p=260}} This concern was so great to Haus that he wrote in September 1914, "So long as the possibility exists that Italy will declare war against us, I consider it my first duty to keep our fleet intact."{{sfn|Halpern|1987|p=30}} Haus' decision to use the Austro-Hungarian Navy as a [[fleet in being]] earned sharp criticism from the [[Austro-Hungarian Army]], the German Navy, and the Austro-Hungarian [[Foreign Ministry of Austria-Hungary|Foreign Ministry]],{{sfn|Sondhaus|1994|p=261}} but it also led to a far greater number of Entente naval forces being devoted to the Mediterranean and the Strait of Otranto. These could have been used elsewhere, such as against the Ottoman Empire during the [[Gallipoli Campaign]].{{sfn|Sondhaus|1994|pp=380–381}}

The most important factor contributing to the ''Tegetthoff''s spending most of their time at port may have been the lack of coal. Prior to the war, the United Kingdom had served as Austria-Hungary's primary source for coal. In the years before the war an increasing percentage of coal had come from mines in Germany, [[Virginia]] in the United States, and from domestic sources, but 75% of the coal purchased for the Austro-Hungarian Navy came from Britain. The outbreak of war meant that these sources, as well as those from Virginia, would no longer be available. Significant quantities of coal had been stockpiled before the war however, ensuring the navy was capable of sailing out of port if need be. Even so, the necessity of ensuring the navy's most important ships such as the ''Tegetthoff''s had the coal they needed in the event of an Italian or French attack or a major offensive operation resulted in the dreadnoughts remaining at port unless circumstances necessitated their deployment at sea.{{sfn|Sondhaus|1994|p=261}}{{sfn|Halpern|1995|p=144}}

In early 1915 Germany suggested that the Austro-Hungarian Navy conduct an attack on the Otranto Barrage in order to relieve pressure on the Ottoman Empire at the height of the Gallipoli Campaign. Haus rejected the proposal, countering that the French had pulled back their blockade to the southernmost end of the Adriatic Sea, and that none of the Anglo-French ships assigned to blockading the strait had been diverted to the Dardanelles.{{sfn|Sondhaus|1994|pp=266–267}}

Haus also advocated strongly in favor of keeping his battleships, in particular the ships of the ''Tegetthoff'' class, in reserve in the event of Italy's entry into the war on the side of the Entente. Haus believed that Italy would inevitably break her alliance with Austria-Hungary and Germany, and that by keeping Austria-Hungary's battleships safe, they could rapidly be employed against Italy. This strategy enabled Austria-Hungary's battleships to engage the Italians shortly after Italy's declaration of war in May 1915.{{sfn|Sondhaus|1994|pp=269–270}}

==== Bombardment of Ancona ====
{{main|Bombardment of Ancona}}
[[File:Ramberg - Bombarding of Ancona, 1915, HGM, 2017-03-08.jpg|thumb|right|300px|''Bombarding of Ancona'' by August von Ramberg, depicting Austro-Hungarian battleships shelling the Italian coastline in May 1915|alt=A painting depicting multiple battleships in a row shelling a coastline. Smoke can be seen coming out of both the land and the guns of each ship.]]

After failed negotiations with Germany and Austria-Hungary over Italy joining the war as a member of the [[Central Powers]], the Italians negotiated with the [[Triple Entente]] for Italy's eventual entry into the war on their side in the [[Treaty of London (1915)|Treaty of London]], signed on 26 April 1915.{{sfn|Sondhaus|1994|p=272}} On 4 May Italy formally renounced her alliance to Germany and Austria-Hungary, giving the Austro-Hungarians advanced warning that Italy was preparing to go to war against them. On 20 May, Emperor Franz Joseph&nbsp;I gave the Austro-Hungarian Navy authorization to attack Italian ships convoying troops in the Adriatic or sending supplies to Montenegro. Haus meanwhile made preparations for his most valuable battleships to sortie out into the Adriatic in a massive strike against the Italians the moment war was declared. On 23 May 1915, between two and four hours after the Italian declaration of war reached the main Austro-Hungarian naval base at Pola,{{refn|There are two conflicting times given for when the fleet departed Pola. Halpern states that it was four hours until the fleet set sail while Sokol claims that the fleet left Pola two hours after the declaration reached Admiral Haus.|group = lower-alpha}} the Austro-Hungarian fleet, including the three ships of the ''Tegetthoff'' class, departed to bombard the Italian coast.{{sfn|Halpern|1995|p=144}}{{sfn|Sokol|1968|p=107}}

While several ships bombarded secondary targets and others were deployed to the south to screen for Italian ships that could be steaming north from [[Taranto]], the core of the Austro-Hungarian Navy, spearheaded by the ships of the ''Tegetthoff'' class, made their way to [[Ancona]]. The bombardment across the [[province of Ancona]] was a major success for the Austro-Hungarian Navy. In the port of Ancona an Italian steamer was destroyed and three others damaged. An Italian destroyer, ''Turbine'', was sunk further south. The infrastructure of the port of Ancona and the surrounding towns was severely damaged. The railroad yard and port facilities in the city were damaged or destroyed, while local shore batteries defending them were knocked out. Multiple wharves, warehouses, oil tanks, radio stations, and coal and oil stores were set on fire by the bombardment, and the city's electricity, gas, and telephone lines were severed. Within the city itself, Ancona's police headquarters, army barracks, military hospital, sugar refinery, and Bank of Italy offices all saw damage. 30 Italian soldiers and 38 civilians were killed, while an additional 150 were wounded in the attack.{{sfn|Sokol|1968|pp=107–108}}{{sfn|Sondhaus|1994|pp=274–275}}

The Austro-Hungarian ships would later move on to bombard the coast of Montenegro, without opposition; by the time Italian ships arrived on the scene, the Austro-Hungarians were safely back in Pola.{{sfn|Hore|2006|p=180}} The objective of the bombardment of Ancona was to delay the Italian Army from deploying its forces along the border with Austria-Hungary by destroying critical transportation systems.{{sfn|Sokol|1968|p=107}} The surprise attack on Ancona succeeded in delaying the Italian deployment to the [[Alps]] for two weeks. This delay gave Austria-Hungary valuable time to strengthen its Italian border and re-deploy some of its troops from the Eastern and Balkan fronts.{{sfn|Sokol|1968|p=109}} The bombardment also delivered a severe blow to Italian military and public morale.{{sfn|Sondhaus|1994|p=276}}

==== 1916–1917 ====
[[File:SMS Prinz Eugen_underway.png|thumb|left|300px|''Prinz Eugen'' underway on 28 June 1917|alt=A large battleship steams through the water. Water breaks against the bow as heavy dark smoke emerges from the ship's two funnels.]]
Largely unable to engage in major offensive combat operations after the Bombardment of Ancona, the ships were mostly relegated to defending Austria-Hungary's coastline for the next three years.{{sfn|Sokol|1968|p=71}} The lack of combat engagements, or even instances where the ''Tegetthoff''s left port, is exemplified by the career of ''Szent István''. The ship was unable to join her sisters in the Bombardment of Ancona and rarely left the safety of the port except for gunnery practice in the nearby Fažana Strait. She only spent 54 days at sea during her 937 days in service and made only a single two-day trip to Pag Island. In total, only 5.7% of her life was spent at sea; and for the rest of the time she swung at anchor in Pola Harbour. ''Szent István'' saw so little action and so little time at sea that she was never drydocked to have her bottom cleaned.{{sfn|Sieche|1991|pp=, 123, 133}}

In January 1917 [[Charles I of Austria|Emperor Karl&nbsp;I]] attended a military conference at [[Pszczyna Castle|Schloss Pless]] with German Kaiser Wilhelm&nbsp;II and members of the German Army and Navy. Haus, along with members of Austria-Hungary's naval command at Pola, accompanied the Emperor to this conference in order to discuss naval operations in the Adriatic and Mediterranean for 1917. Days after returning from this conference, Grand Admiral Haus died of pneumonia aboard his flagship ''Viribus Unitis'' on 8 February 1917. Newly crowned Karl I attended his funeral in Pola.{{sfn|Sondhaus|1994|p=294}}

Despite his death, Haus' strategy of keeping the Austro-Hungarian Navy, and particularly its dreadnoughts, in port continued. By keeping the ''Tegetthoff''s as a fleet in being, the Austro-Hungarian Navy would be able to continue to defend its lengthy coastline from naval bombardment or invasion by sea. The major ports of Trieste and Fiume would also remain protected. Furthermore, Italian ships stationed in [[Venice]] were effectively trapped by the positioning of the Austro-Hungarian fleet, preventing them from sailing south to join the bulk of the Entente forces at the Otranto Barrage.{{sfn|Sondhaus|1994|pp=294–295}}

Njegovan was promoted to admiral and appointed Commander-in-Chief of the Navy. With Njegovan appointed to higher office, command of the 1st Battle Division, which consisted of all four ''Tegetthoff''-class ships, fell to Vice-Admiral [[Anton Willenik]]. Njegovan had previously voiced frustration watching the dreadnoughts he had commanded under Haus sit idle at port and upon taking command he had some 400,000 tons of coal at his disposal, but he chose to continue the strategy of his predecessor. Despite a change in command of both the Austro-Hungarian Navy and the Empire which it served, there would be no change in strategy regarding the employment of the ''Tegetthoff'' class in battle.{{sfn|Sondhaus|1994|p=304}}

Having hardly ever ventured out to port except to conduct gunnery practice for the past two years, the most significant moments the ''Tegetthoff''-class ships saw while moored in Pola were inspections by dignitaries. The first such visit was conducted by Emperor Karl&nbsp;I on 15 December 1916. During this brief visit the Emperor inspected Pola's naval establishments and ''Szent István''.{{sfn|Sieche|1991|p=122}} Karl&nbsp;I returned to Pola in June 1917 in the first formal imperial review of the Austro-Hungarian Navy since 1902. This visit was far grander than his previous trip to the naval base, with officers and sailors crowding the decks of their ships at port and the naval ensign of Austria-Hungary flying from every vessel. The Emperor received multiple cheers and salutes from the men at Pola, who had spent the past two years doing little more than shooting down Italian airplanes and airships.{{sfn|Sondhaus|1994|p=309}} The third dignitary visit came during Kaiser Wilhelm&nbsp;II's inspection of Pola's German submarine base on 12 December 1917. During this trip, the German Emperor also took the time to inspect ''Szent István'' in similar fashion to his Austro-Hungarian counterpart. Aside from these visits, the only action the port of Pola and the ''Tegetthoff''s were subject to between the Bombardment of Ancona and the summer of 1918 were the more than eighty air raids conducted by the newly formed [[Corpo Aeronautico Militare|Italian Air Force]].{{sfn|Sieche|1991|pp=120, 122–123}}

==== 1918 ====
[[File:Gulf of Taranto map.png|thumb|250px|Map showing the location of the Straits of Otranto at the southern end of the Adriatic|alt=A map showing the Strait of Otranto. The southeastern tip of Italy can be seen on the left, with the coast of Albania appearing on the right.|right]]
Following the [[Cattaro Mutiny]] in February 1918, Admiral Njegovan was fired as Commander-in-Chief of the Navy, though at Njegovan's request it was announced that he was retiring.{{sfn|Sondhaus|1994|p=144}} [[Miklós Horthy|Miklós Horthy de Nagybánya]], commander of ''Prinz Eugen'', was promoted to [[rear admiral]] and named Commander-in-Chief of the Fleet. Horthy's promotion was met with support among many members of the naval officer corps, who believed he would use Austria-Hungary's navy to engage the enemy. Horthy's appointment did however pose difficulties. His relatively young age alienated many of the senior officers, and Austria-Hungary's naval traditions included an unspoken rule that no officer could serve at sea under someone of inferior seniority. This meant that the heads of the First and Second Battle Squadrons, as well as the Cruiser Flotilla, all had to go into early retirement.{{sfn|Sondhaus|1994|p=326}}

In March 1918 Horthy's position within the navy was secured, and he had begun to reorganize it according to his own vision, with strong support from Emperor Karl&nbsp;I. By this time, the [[United States]] had [[American entry into World War I|declared war]] on both Germany and Austria-Hungary and had begun to send ships to aid the French, British, and Italians in the Mediterranean Sea. Horthy had inherited an "Austrian lake" in the Adriatic Sea, according to the [[United States Navy]],{{sfn|Halpern|1987|p=439}} and shipping of supplies, troops, sick and wounded personnel, and military equipment across various ports in the Adriatic was done with little to no opposition from the [[Allies of World War I|Allied Powers]]. American planning for a naval offensive to sweep the Adriatic and even land up to 20,000 [[United States Marine Corps|marines]] with naval and infantry support from Britain, France, and Italy were halted by the onset of the [[German spring offensive]] in France, launched on 21 March 1918.{{sfn|Sondhaus|1994|p=329}} Horthy used these first few months as Commander-in-Chief to finish his re-organization of the navy. As one of Njegovan's final actions before he was ousted entailed shifting several smaller and older vessels around to different ports under Austro-Hungarian control, the only ships which remained at port in Pola aside from the three of the ''Radetzky'' class were the four dreadnoughts of the ''Tegetthoff'' class, which had now fallen under the command of Captain Heinrich Seitz. Horthy worked to re-locate as many ships as he could back to Pola in order to maximize the threat the Austro-Hungarian Navy posed to the Allied Powers. Horthy also used his appointment to take the Austro-Hungarian fleet out of port for maneuvers and gunnery practice on a regular basis. The size of these operations were the largest the navy had seen since the outbreak of the war.{{sfn|Sondhaus|1994|pp=330, 333}}

These gunnery and maneuver practices were conducted not only to restore order in the wake of several failed mutinies, but also to prepare the fleet for a major offensive operation. Horthy's strategic thinking differed from his two predecessors, and shortly after assuming command of the navy he resolved to undertake a major fleet action in order to address low morale and boredom, and make it easier for Austro-Hungarian and German U-boats to break out of the Adriatic into the Mediterranean. After several months of practice, Horthy concluded the fleet was ready for a major offensive at the beginning of June 1918.{{sfn|Sondhaus|1994|p=334}}

==== Otranto Raid ====
[[File:SMS_Tegetthoff_Otranto.png|thumb|left|300px|''Szent István'' sinking in June 1918 after being struck by an Italian torpedo. ''Tegetthoff'' can be seen on the right|alt=A battleship lies low in the water with a heavy list after being struck by a torpedo. Another battleship can be seen floating in the background close by.]]
Horthy was determined to use the fleet to attack the Otranto Barrage. Planning to repeat his [[Battle of the Strait of Otranto (1917)|successful raid on the blockade in May 1917]],{{sfn|Koburger|2001|p=104}} Horthy envisioned a massive attack on the Allied forces with his four ''Tegetthoff''-class ships providing the largest component of the assault. They would be accompanied by the three ships of the ''Erzherzog Karl''-class pre-dreadnoughts, the three {{sclass|Novara|cruiser|2}}s, the cruiser ''Admiral Spaun'', four {{sclass|Tátra|destroyer|2}}s, and four torpedo boats. Submarines and aircraft would also be employed in the operation to hunt down enemy ships on the flanks of the fleet.{{sfn|Halpern|1987|p=501}}{{sfn|Sondhaus|1994|p=335}}{{sfn|Sokol|1968|p=134}}

On 8 June 1918 Horthy took his flagship, ''Viribus Unitis'', and ''Prinz Eugen'' south with the lead elements of his fleet.{{sfn|Koburger|2001|p=104}} On the evening of 9 June, ''Szent István'' and ''Tegetthoff'' followed along with their own escort ships. Horthy's plan called for {{SMS|Novara|1913|2}} and {{SMS|Helgoland|1912|2}} to engage the Barrage with the support of the ''Tátra''-class destroyers. Meanwhile, ''Admiral Spaun'' and {{SMS|Saida|1912|2}} would be escorted by the fleet's four torpedo boats to [[Otranto]] to bombard Italian air and naval stations. The German and Austro-Hungarian submarines would be sent to [[Vlorë|Valona]] and Brindisi to ambush Italian, French, British, and American warships that sailed out to engage the Austro-Hungarian fleet, while seaplanes from [[Cattaro]] would provide air support and screen the ships' advance. The battleships, and in particular the ''Tegetthoff''s, would use their firepower to destroy the Barrage and engage any Allied warships they ran across. Horthy hoped that the inclusion of these ships would prove to be critical in securing a decisive victory.{{sfn|Sondhaus|1994|p=335}}

En route to the harbour at [[Slano|Islana]], north of [[Dubrovnik|Ragusa]], to rendezvous with ''Viribus Unitis'' and ''Prinz Eugen'' for the coordinated attack on the Otranto Barrage, ''Szent István'' and ''Tegetthoff'' attempted to make maximum speed in order to catch up to the rest of the fleet. In doing so, ''Szent István''{{'}}s turbines started to overheat and speed had to be reduced to {{convert|12|kn|sp=us}}. When an attempt was made to raise more steam in order to increase to {{convert|16|kn|sp=us}} ''Szent István'' produced an excess of smoke. At about 3:15&nbsp;am on 10 June,{{refn|Debate exists over what was the exact time when the attack took place. Sieche states that the time was 3:15&nbsp;am when ''Szent István'' was hit while Sokol claims that the time was 3:30&nbsp;am.|group = lower-alpha}} two Italian [[MAS (boat)|MAS boats]], ''MAS-15'' and ''MAS-21'', spotted the smoke from the Austrian ships while returning from an uneventful patrol off the Dalmatian coast. The MAS platoon was commanded by [[Corvette Captain|''Capitano di corvetta'']] [[Luigi Rizzo]], who had sunk the Austro-Hungarian coastal defense ship {{SMS|Wien}} in Trieste six months before.{{sfn|Sokol|1968|p=135}} The individual boats were commanded by ''Capo timoniere'' Armando Gori and [[Ensign (rank)|''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 to hit the ship.{{sfn|Sokol|1968|p=135}} ''MAS-15'' fired her two torpedoes successfully at 3:25&nbsp;am at ''Szent István''. Both boats evaded any pursuit although ''MAS-15'' had to discourage the Austro-Hungarian torpedo boat [[Yugoslav torpedo boat T1|''Tb 76 T'']] by dropping [[depth charge]]s in her wake. ''Tegetthoff'', thinking that the torpedoes were fired by [[submarine]]s, pulled out of the formation and started to [[zigzag]] to throw off any further attacks. She repeatedly fired on suspected submarine [[periscope]]s.{{sfn|Sieche|1991|pp=127, 131}}

[[File:A Szent István csatahajó pusztulása.ogv|thumb|300px|Film footage about the sinking of ''Szent István''|alt=A large battleship lists in the water as the crew evacuates the vessel before it capsizes.]]
''Szent István'' was hit by two {{convert|45|cm|adj=on|0|sp=us}} torpedoes abreast her boiler rooms. The aft boiler room quickly flooded and gave the ship a 10° list to starboard. Counterflooding of the portside trim cells and [[magazine (artillery)|magazines]] reduced the list to 7°, but efforts to use collision mats to plug the holes failed. While this was going on the dreadnought steered for the nearby [[Molat (island)|Bay of Brgulje]] at low speed, before eventually coming to a halt in order to provide additional power to the ship's pumps, which could discharge {{convert|6000|t|LT|0|sp=us}} of water per hour. However, water continued to leak into the forward boiler room and eventually doused all but the two boilers on the port side. This killed the power for the pumps and only left enough electricity to run the lights. The turrets were trained to port in a futile effort to counter the list and their ready ammunition was thrown overboard.{{sfn|Sieche|1991|pp=127, 131}}{{sfn|Sondhaus|1994|p=335}} Upon returning to the formation at 4:45&nbsp;am, ''Tegetthoff'' attempted to take ''Szent István'' in tow, which failed.{{sfn|Noppen|2012|p=42}} Many of the crew members of the sinking battleship assembled on the deck to use their weight along with the turned turrets as a [[counterbalance]], but the ship was taking on too much water, with her watertight bulkheads giving way to the flooding one by one.{{sfn|Prasky|1978|p=106}} ''Szent István''{{'}}s chaplain performed one final blessing while the crew of ''Tegetthoff'' emerged onto her decks to salute the sinking ship. At 6:12&nbsp;am, with the pumps unequal to the task, ''Szent István'' capsized off [[Premuda]]. 89 sailors and officers died in the sinking, 41 of them from Hungary. The low death toll can be partly attributed to the long amount of time it took for the battleship to sink, and the fact that all sailors with the Austro-Hungarian Navy had to learn to swim before entering active service.{{sfn|Sieche|1991|pp=127, 131}}{{sfn|Sondhaus|1994|p=335}}{{sfn|Sokol|1968|pp=134–135}} The captain of ''Szent István'', Heinrich Seitz, [[The captain goes down with the ship|was prepared to go down with his ship]] but was saved after being thrown off the bridge when she capsized.{{sfn|Sondhaus|1994|p=336}}

Film footage and photographs exist of ''Szent István''{{'}}s last half-hour, taken by [[Captain Lieutenant|''Linienschiffsleutnant'']] Meusburger of ''Tegetthoff'' with his own camera and by an official film crew. The two films were later spliced together and exhibited in the United States after the war.{{sfn|Sokol|1968|p=135}} The battleship's sinking was one of only two on the high seas to ever be filmed, the other being that of the British battleship {{HMS|Barham|04|6}} during [[World War&nbsp;II]].{{sfn|Sieche|1991|p=131}} Proceeds from the film of ''Szent István'' capsizing were eventually used to feed children in Austria following the ending of the war.{{sfn|Sokol|1968|p=135}}

Fearing further attacks by torpedo boats or destroyers from the Italian navy, and possible Allied dreadnoughts responding to the scene, Horthy believed the element of surprise had been lost and called off the attack. In reality, the Italian torpedo boats had been on a routine patrol, and Horthy's plan had not been betrayed to the Italians as he had feared. The Italians did not even discover that the Austrian dreadnoughts had departed Pola until 10 June when aerial reconnaissance photos revealed that they were no longer there.{{sfn|Sieche|1991|p=135}} Nevertheless, the loss of ''Szent István'' and the blow to morale it had on the navy forced Horthy to cancel his plans to assault the Otranto Barrage. The fleet returned to the base at Pola where it would remain for the rest of the war.{{sfn|Sokol|1968|pp=134–135}}{{sfn|Sondhaus|1994|p=336}}

==== End of the war ====
{{main|Raid on Pola}}
[[File:SMS_Viribus_Unitis_Sinking.png|thumb|left|''Viribus Unitis'' sinking in Pola on 1 November 1918.]]

On 17 July 1918, Pola was struck by the largest air raid the city would see during the war. 66 Allied planes dropped over 200 bombs, though none of the ''Tegetthoff''s were hit or damaged in the attack.{{sfn|Sondhaus|1994|p=337}}

By October 1918 it had become clear that Austria-Hungary was facing defeat in the war. With various attempts to quell nationalist sentiments failing, Emperor Karl&nbsp;I decided to sever Austria-Hungary's alliance with Germany and appeal to the Allied Powers in an attempt to preserve the empire from complete collapse. On 26 October Austria-Hungary informed Germany that [[Dual Alliance (1879)|their alliance]] was over. In Pola the Austro-Hungarian Navy was in the process of tearing itself apart along ethnic and nationalist lines. Horthy was informed on the morning of 28 October that an armistice was imminent, and used this news to maintain order and prevent a mutiny among the fleet. While a mutiny was avoided, tensions remained high and morale was at an all-time low. The situation was so stressful for members of the navy that the captain of ''Prinz Eugen'', Alexander Milosevic, committed suicide in his quarters aboard the battleship.{{sfn|Sondhaus|1994|pp=350–351}}

On 29 October, the [[State of Slovenes, Croats and Serbs#National Council|National Council]] in [[Zagreb]] announced Croatia's dynastic ties to Hungary had come to a formal conclusion. The National Council also called for Croatia and Dalmatia to be unified, with Slovene and Bosnian organizations pledging their loyalty to the newly formed government. This new provisional government, while throwing off Hungarian rule, had not yet declared independence from Austria-Hungary. Thus Emperor Karl&nbsp;I's government in Vienna asked the newly formed [[State of Slovenes, Croats and Serbs]] for help maintaining the fleet stationed at Pola and keeping order among the navy. The National Council refused to assist unless the Austro-Hungarian Navy was first placed under its command.{{sfn|Sondhaus|1994|pp=351–352}} Emperor Karl&nbsp;I, still attempting to save the Empire from collapse, agreed to the transfer, provided that the other "nations" which made up Austria-Hungary would be able to claim their fair share of the value of the fleet at a later time.{{sfn|Sondhaus|1994|p=352}} All sailors not of Slovene, Croatian, Bosnian, or Serbian background were placed on leave for the time being, while the officers were given the choice of joining the new navy or retiring.{{sfn|Sondhaus|1994|p=352}}{{sfn|Sokol|1968|pp=136–137, 139}}

The Austro-Hungarian government thus decided to hand over the bulk of its fleet to the State of Slovenes, Croats and Serbs without a shot being fired. This was considered preferential to handing the fleet to the Allies, as the new state had declared its neutrality. Furthermore, the newly formed state had also not yet publicly dethroned Emperor Karl&nbsp;I, keeping the possibility of reforming the Empire into a triple monarchy alive. The transfer to the State of Slovenes, Croats and Serbs began on the morning of 31 October, with Horthy meeting representatives from the South Slav nationalities aboard his flagship, ''Viribus Unitis''. After "short and cool" negotiations, the arrangements were settled and the handover was completed that afternoon. The Austro-Hungarian Naval Ensign was struck from ''Viribus Unitis'', and was followed by the remaining ships in the harbor. After the transfer, Horthy took with him from his personal cabin a portrait of Emperor Franz Joseph&nbsp;I, which the late Emperor had gifted to the battleship, along with the ceremonial silk ensign of ''Viribus Unitis'', and Horthy's own personal admiral's flag. That evening ''Viribus Unitis'' was renamed ''Jugoslavija''.{{sfn|Koburger|2001|p=118}} Control over the battleship, and the head of the newly established navy for the State of Slovenes, Croats and Serbs, fell to Captain [[Janko Vuković]], who was raised to the rank of admiral and took over Horthy's old responsibilities as Commander-in-Chief of the Fleet.{{sfn|Sondhaus|1994|pp=353–354}}{{sfn|Sokol|1968|pp=136–137, 139}}

On 1 November 1918, the transfer being still unknown to Italy, two men of the Italian Regia Marina, Raffaele Paolucci and [[Raffaele Rossetti]], rode a primitive manned torpedo (nicknamed ''[[Mignatta]]'' or "leech") into the naval base at Pola. Using limpet mines, they attacked ''Jugoslavija'' and the freighter ''Wien''.<ref name="Warhola" /> Traveling down the rows of battleships, the two men encountered ''Jugoslavija'' at around 4:40&nbsp;am. Rossetti placed one canister of TNT on the hull of the battleship, timed to explode at 6:30&nbsp;am. He then flooded the second canister, sinking it on the harbor floor close to the ship.  The men had no [[Scuba set|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 ''Viribus Unitis'', along with most of the Austro-Hungarian fleet, to the State of Slovenes, Croats and Serbs. They were taken aboard ''Jugoslavija'', where they informed her new captain of what they had done but did not reveal the exact position of the explosives.<ref name="Warhola" /> Vuković then arranged for the two prisoners to be taken safely to the sister ship ''Tegetthoff'', and ordered the evacuation of the ship.{{sfn|Noppen|2012|p=44}} The explosion did not happen at 6:30&nbsp;am as predicted and Vuković, believing mistakenly that the Italians had lied, returned to the ship with many sailors. When the mines exploded shortly afterwards at 6:44&nbsp;am, the battleship sank in 15&nbsp;minutes; Vuković and 300–400 of the crew went down with her. The second explosive canister, lying on the bottom, exploded close to the freighter ''Wien'', resulting in her sinking.<ref name="Warhola" /> The two Italians were interned for a few days until the end of the war and were honored by the [[Kingdom of Italy (1861–1946)|Kingdom of Italy]] with the [[Gold Medal of Military Valor]].<ref name="difesa.it Rossetti" /><ref name="difesa.it Paolucci" />{{sfn|Halpern|1987|p=567}}{{sfn|Sokol|1968|p=139}}