U - 10 - class submarine The " U - 10 " class was a class of five submarine s or U - boats of the Austro - Hungarian Navy ( ) during World War I . The class was similar to the German Type UB I submarine of the German Imperial Navy ( ) ; the first two boats delivered to Austria - Hungary had previously been commissioned in Kaiserliche Marine . The " U - 10 " class as a whole did not have much wartime success , with three of the boats sinking either one or no ships . Only one boat , sank more than of enemy ships . Of the five submarines of the class , only was sunk during the war ; the remaining four were delivered as war reparations and broken up by 1920 . Background . The Austro - Hungarian Navy ' s U - boat fleet at the beginning of World War I consisted of six largely experimental submarines , two of which were not operational . The Navy did have five s under construction in Germany , but a perceived inability to sail the completed submarines past Gibraltar to Pola led to a hasty decision to sell them to Germany , a severe setback for Austria - Hungary ' s U - boat fleet . In order to bolster their fleet , which had already been boosted by the recovery and commissioning of the French submarine " Curie " as " U - 14 " in 1915 , the Austro - Hungarian Navy purchased five German UB - type coastal submarines , which had the advantages of short construction time and the ability to be shipped by rail — which avoided the perceived pitfalls of sea delivery . The first contract in February 1915 secured the purchase of and , initially commissioned as the German Type UB I U - boats " UB - 1 " and " UB - 15 " , respectively . A further contract on 1 April 1915 , purchased three more boats , , , and . Design and construction . The " U - 10 " - class boats were small coastal submarines that displaced surfaced and submerged . For propulsion , they featured a single shaft , a single diesel engine for surface running , and a single electric motor for submerged travel . The boats were capable of while surfaced and while submerged at a diving depth of up to . All five had slightly different conning tower configurations , but were all designed for a crew of 17 officers and men . The lead boat of the class , " U - 10 " , was built by Germaniawerft of Kiel , while the other four were constructed by AG Weser of Bremen . All five were transported by rail in sections to Pola , where they only needed riveting together to be complete , a process that typically took about two weeks . " U - 10 " was the first ship of the class launched , as the German " UB - 1 " on 22 January 1915 . The other four boats were launched by April . " UB - 1 " and " UB - 15 " were initially commissioned into the " Kaiserliche Marine " in January and April , respectively , each with German commanders and crew , but with an Austro - Hungarian Navy officer for piloting and training purposes , but both were commissioned into the " K . u . K . Kriegsmarine " with Austro - Hungarian crews by July . The other three ships were never manned by German crews and had all been commissioned by early October when each is listed in sources with a commanding officer . Armament . The " U - 10 " class boats were equipped with two torpedo tubes located in the front and carried a complement of two torpedoes . The German Type UB I submarines were additionally equipped with a machine gun , but it is not clear from sources if " U - 10 " and " U - 11 " , the former German boats , were either equipped with them or , if so , retained them in Austro - Hungarian service . In October 1916 , all the boats except " U - 11 " received 37 mm / 23 ( 1 . 5 in ) quick - firing ( QF ) guns . " U - 11 " received a 66 mm / 18 ( 2 . 6 in ) gun originally planned for " U - 14 " ( which received a larger gun instead ) . In November 1917 , the 37 mm guns were replaced by 47 mm / 23 ( 1 . 9 in ) QF guns . War activities . All five boats of the " U - 10 " class took part in the war , but , as a class , had limited success . Although " UB - 1 " and " UB - 15 " had each had sunk a single ship while commissioned in the German Imperial Navy during 1915 , neither boat sank any ships in Austro - Hungarian service . " U - 17 " torpedoed a single ship , the Italian destroyer " Impetuoso " , which sank on 10 July 1916 . " U - 16 " sank two small sailing ships in late 1915 and torpedoed and sank the Italian destroyer " Nembo " on 16 October 1916 . " U - 15 " was the most successful of the class , sinking six ships for a total of . On a single day , 25 June 1916 , " U - 15 " sank the Italian auxiliary cruiser and the French destroyer " Fourche " in the Strait of Otranto , accounting for almost half of her wartime successes . Of the five boats , only " U - 16 " was sunk during the war , shortly after sinking " Nembo " . The only other casualty among the class involved " U - 10 " , which hit a mine near Caorle and was beached with heavy damage . Although she was looted by Austro - Hungarian Army troops , she was later towed to Trieste for repairs which remained incomplete at the war ' s end . After the end of fighting in November 1918 , the four surviving class members — " U - 10 " , " U - 11 " , " U - 15 " , and " U - 17 " — were all turned over to Italy as war reparations and scrapped at Pola by 1920 . Class members . SM " U - 10 " . SM " U - 10 " was the lead boat of the " U - 10 " class of submarines for the Austro - Hungarian Navy , but was originally named " UB - 1 " as a part of the German Imperial Navy . She was laid down on 1 November 1914 in Germany and shipped by rail to Pola where she was assembled and launched on 22 January 1915 . Commissioned one week later as SM " UB - 1 " , she sank one Italian torpedo boat in her German service . In July , she was handed over to the Austro - Hungarian Navy and commissioned as SM " U - 10 " . She was the target of an unsuccessful torpedo attack by a British submarine in May 1917 . In July 1918 , " U - 10 " hit a mine and was beached with heavy damage . She was towed to Trieste for repairs which remained unfinished at the war ' s end . She was handed over to Italy as a war reparation and scrapped in 1920 . SM " U - 11 " . SM " U - 11 " was also originally a part of the German Imperial Navy , under the name " UB - 15 " . She was laid down on 9 November 1914 in Germany and shipped by rail to Pola where she was assembled , launched , and commissioned as SM " UB - 15 " on 11 April 1915 . In her only wartime success , she sank an Italian submarine in German service in early June . Shortly thereafter , she was delivered to the Austro - Hungarian Navy and commissioned as SM " U - 11 " on 14 June . In early 1916 , " U - 11 " made a torpedo attack on a British submarine but missed . She was delivered to Italy as a war reparation and scrapped in 1920 . SM " U - 15 " . SM " U - 15 " was constructed in Germany and shipped by rail to Pola where she was assembled and launched in September 1915 and commissioned on 6 October . " U - 15 " was the most successful boat of the " U - 10 " class , sinking six ships totaling more than . She survived the war and was ceded to Italy as a war reparation and scrapped in 1920 . SM " U - 16 " . SM " U - 16 " was constructed in Germany and shipped by rail to Pola where she was assembled and launched on 26 April 1915 and commissioned on 6 October . " U - 16 " sank one ship in November 1915 and seized another in December . While operating in the Adriatic off the coast of Albania in mid - October 1916 , " U - 16 " sank an Italian destroyer acting as a convoy escort . " U - 16 " was sunk in the ensuing action , but sources are not clear on the exact cause of her sinking . SM " U - 17 " . SM " U - 17 " was constructed in Germany and shipped by rail to Pola where she was assembled and launched on 21 April 1915 and commissioned on 6 October . " U - 17 " sank an Italian destroyer in July 1916 as part of an effort to disrupt the Otranto Barrage but sank no other ships during the war . The boat survived the war and was delivered to Italy as a war reparation and scrapped in 1920 .