SMS Szent István SMS " Szent István " was a dreadnought of the Austro - Hungarian Navy , the only one built in the Hungarian part of Austria - Hungary . The Ganz & Company ' s Danubius Yard in Hungarian - owned Fiume ( Rijeka ) was awarded the contract to build the battleship in return for the Hungarian government agreeing to the 1910 and 1911 naval budgets . She was named after Hungary ' s first Christian king , Saint Stephen ( ) . She , and her sister ships , were regarded as very compact and powerful ships and were the first dreadnoughts in service with triple main - gun turrets . Her completion was delayed by the start of World War I , but she was commissioned in December 1915 . She spent the bulk of the war at anchor in Pola ( Pula ) , leaving harbour generally only for gunnery training . Her final mission began on the evening of 9 June 1918 when she sailed to rendezvous with the other dreadnoughts for an attack on the Otranto Barrage , scheduled for the following day . Two Italian MAS , a type of Motor Torpedo Boat , discovered " Szent István " and her half - sister early in the morning of 10 June 1918 while returning after a night patrol off the Dalmatian coast . They penetrated past her escorts and torpedoed her twice abreast her boiler rooms . They flooded , which knocked out power to the pumps , and " Szent István " capsized less than three hours after being torpedoed . All but 89 of her crew were rescued . She is the only battleship whose sinking was filmed during World War I . Her wreck was discovered in the mid - 1970s , upside down , off the Croatian island of Premuda . She has been declared a protected site by the Croatian Ministry of Culture and casual diving is forbidden . Design . " Szent István " differed from her half - sisters mainly in her machinery . She only had two shafts and two turbines , unlike the four shaft arrangement of the other ships of her class . External differences included a platform built around the fore funnel which extended from the bridge to the after funnel and on which several searchlights were installed . A further distinguishing feature was the modified ventilator trunk in front of the mainmast . She was the only ship of her class not to be fitted with torpedo nets . General characteristics . " Szent István " had an overall length of , a beam of , and a draught of at deep load . She displaced at load and at deep load . The skeg for each propeller shaft was a solid , blade - like fitting , unlike the strut - type skegs used in her half - sisters , that had such a high transversal resistance that the rudder could only be laid at a maximum angle of 10° at full speed to avoid a heavy list . The hull was built with a double bottom deep with a reinforced inner bottom that consisted of two layers of plates . " Szent István " had two AEG - Curtis steam turbines , each of which was housed in a separate engine - room . The turbines were powered by twelve Babcock & Wilcox boilers in two boiler rooms . The turbines were designed to produce a total of , enough for her designed speed of , but no figures from her 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 . " Szent István " 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 pivot mounts 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 . The waterline armour belt of the " Tegetthoff " - class dreadnoughts measured thick 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 the bow or the stern . It was continued to the bow by a small patch of armour . The upper armour belt had a maximum thickness of , but it thinned to 110 millimeters 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 of armour , except for the turret and conning tower roofs which were thick . The thickness of the decks ranged from in two layers . The underwater protection system consisted of the extension of the double bottom up to the lower edge of the waterline armour belt , with a thin plate acting as the outermost bulkhead . It was backed by a torpedo bulkhead that consisted of two layered 25 - millimetre plates . The total thickness of this system was only which made it incapable of containing a torpedo warhead detonation or mine explosion without rupturing . Construction . " Szent István " was laid down on 29 January 1912 at Ganz & Company ' s Danubius yard at Fiume ( Rijeka ) , the only large Hungarian shipyard in Croatia as , commemorating the Hungarian national hero . Ganz & Company was awarded the contract to build the battleship in return for the Hungarian government agreeing to the 1910 and 1911 naval budgets . This involved great expense by the Hungarian government , as the yard had hitherto only built smaller merchant ships for , amongst others , , and therefore had to be itself refitted for the building of larger vessels . However she was renamed " " by order of the Emperor Franz Joseph before she was launched on 17 January 1914 . It was customary for either the Emperor or his heir to be present at the launching of a major warship , but Franz Joseph was too feeble and his heir , Archduke Franz Ferdinand , refused to be there as a consequence of his anti - Hungarian attitudes . Franz Joseph sent a telegram of congratulations that negated the snub offered by his heir . During the launching itself there was an accident when the starboard anchor had to be dropped to prevent the ship from hitting a ship carrying spectators , but the anchor chain had not been shackled to the ship and it struck two dockworkers , killing one and crushing the arm of the other . Her fitting out was delayed by the start of the war , but she was finally commissioned on 13 December 1915 . Service . " Szent István " was based at Pola ( Pula ) for the duration of her career . In fact she rarely left 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 . Only 5 . 7 % of her life was spent at sea ; for the rest of the time she swung at anchor in Pola Harbour . She was never even drydocked to get her bottom cleaned . 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 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 . Sinking . By 1918 , the Allies had strengthened their blockade on the Strait of Otranto . As a result , it was becoming more difficult for German and Austro - Hungarian U - boats to get through the strait and into the Mediterranean . In response to these new measures at blockading the straits , the new commander of the Austro - Hungarian Navy , Konteradmiral Miklós Horthy decided to launch an attack on the Allied defenders with battleships , scout cruisers , and destroyers . During the night of 8 June , Horthy left the naval base of Pola with " Viribus Unitis " and " Prinz Eugen " . At about 11 : 00 pm on 9 June 1918 " Szent István " and " Tegetthoff " , escorted by one destroyer and six torpedo boat s , departed Pola , after some troubles getting the harbour defense barrage opened . They were en route to the harbour at Slano , north of Dubrovnik ( Ragusa ) to rendezvous with " Viribus Unitis " and " Prinz Eugen " , for a coordinated attack on the Otranto Barrage . At about 3 : 15 am on 10 June , two Italian 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 " Capitano di corvetta " Luigi Rizzo , who had sunk the Austro - Hungarian coastal defense ship in Trieste six months before . 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 to hit the ship . " MAS 15 " fired her two torpedoes successfully at 3 : 25 am at " Szent István " . Both boats evaded any pursuit although " MAS 15 " had to discourage the torpedo boat by dropping depth charge s in her wake . " Tegetthoff " thought that the torpedoes were fired by submarine s and pulled out of the formation and started to zigzag to throw off any further attacks . She repeatedly fired on suspected submarine periscope s until she rejoined her half - sister at 4 : 45 . " Szent István " was hit by two 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 s 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 Bay of Brgulje at low speed . 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 pointless effort to counter the list and their ready ammunition was thrown overboard . An attempt by " Tegetthoff " to take the crippled battleship into tow was also abandoned after it became clear that " Szent István " was doomed . Flooding continued , and " Szent István " capsized at 6 : 05 am off Premuda Island . Only 89 sailors died — 41 from Hungary — the low death toll partly attributed to the fact that all sailors with the KuK Navy had to learn to swim before entering active service . Film footage exists of " Szent István " s last half - hour , taken by " Linienschiffsleutnant " Meusburger of the " Tegetthoff " with his own camera as well as by an official film crew . The two films were later spliced together and exhibited in the United States during the Great Depression . The wreck of the " Szent István " was located in the mid - 1970s by the SFR Yugoslav Navy . She is upside down at a depth of . Her bow broke off when it hit the seabed while the stern was still afloat , but is immediately adjacent to the rest of the heavily encrusted hull . The two holes from the torpedo hits are visible in the side of the ship as is another deep hole which may be from a torpedo fired at " Tegetthoff " by " MAS 21 " . She is a protected site of the Croatian Ministry of Culture and diving is forbidden without permission . In 2008 , divers from Hungary placed a wreath on the " Szent István " s wreck during a ceremony that was attended by members of the Austrian and Croatian governments . All three countries were once part of the Austro - Hungarian Empire . Consequences . Konteradmiral Miklós Horthy , commander of the proposed attack , cancelled the attack because he thought that the Italians had discovered his plan and ordered the ships to return to Pola . In fact 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 . " Capitano di fregata " Luigi Rizzo was awarded his second Gold Medal of Military Valor , his first was for sinking the pre - dreadnought battleship in 1917 , and appointed a knight in the Order of the Crown of Italy . After the war " MAS 15 " was installed in the Monument to Vittorio Emanuele II as part of the Museo del Risorgimento in Rome . The anniversary of the sinking has been celebrated by the Regia Marina , and its successor , the Marina Militare , as its Navy Day ( ) . Notes . Explanatory notes Citations