U - 27 - class submarine ( Austria - Hungary ) The " U - 27 " class was a class of eight submarine s or U - boats built for and operated by the Austro - Hungarian Navy ( ) during World War I . The class was based upon the German Type UB II design of the German Imperial Navy and was constructed under license in Austria - Hungary . After the Austro - Hungarian Navy had filled its most urgent needs for submarines after the outbreak of World War I , they selected the German Type UB II design for its next group of submarines in mid 1915 . Orders for the first six boats were placed in October 1915 with the Austrian firm of Cantiere Navale Triestino and the Hungarian firm of Ganz Danubius . Two more boats were ordered in 1916 , bringing the class total to eight . The boats were just over long and were armed with two bow torpedo tubes , a deck gun , and a machine gun . For propulsion they were equipped with twin diesel engines for surface running and twin electric motors for subsurface movement . Although the class was based on the German design , the Austro - Hungarian U - boats were heavier and slightly faster underwater , but less heavily armed than their German counterparts All eight boats were commissioned into the Austro - Hungarian Navy between 1917 and 1918 and saw active service during the war . and were the most successful in terms of ships sunk and gross register tonnage sunk , respectively . Two boats sank only one ship each , and a third , , sank no ships . " U - 30 " was also the only boat of the class to be lost during the war . The remaining seven were ceded to France and Italy as war reparations and six were scrapped by 1920 ; the seventh sank while being towed to Bizerta for scrapping . Background . Austria - Hungary ' s U - boat fleet was largely obsolete at the outbreak of World War I . The Austro - Hungarian Navy satisfied its most urgent needs by purchasing five Type UB I submarines that comprised the from Germany , by raising and recommissioning the sunken French submarine " Curie " as , and by building four submarines of the that were based on the 1911 Danish " Havmanden " class . After these steps alleviated their most urgent needs , the Austro - Hungarian Navy selected the German Type UB II design for its newest submarines in mid 1915 . The Germans were reluctant to allocate any of their wartime resources to Austro - Hungarian construction , but were willing to sell plans for up to six of the UB II boats to be constructed under license in Austria - Hungary . The Navy agreed to the proposal and purchased the plans from AG Weser of Bremen . Design . The " U - 27 " - class boats were coastal submarines that displaced surfaced and submerged . The boats had a single hull with saddle tank s , and were long with a beam of and a draft of . For propulsion , they featured two shafts , twin diesel engines of for surface running , and twin electric motors of for submerged travel . The boats were capable of while surfaced and while submerged . Although there is no specific notation of a range for the " U - 27 " class , the German UB II boats , upon which the class was based , had a range of over at surfaced , and at submerged . The " U - 27 " class boats were designed for a crew of 23 – 24 . The " U - 27 " class boats were armed with two bow torpedo tubes and carried a complement of four torpedoes . They were also equipped with a 75 mm / 26 ( 3 . 0 in ) deck gun and an machine gun . Differences from the Type UB II submarines . Although the " U - 27 " design was based on the German Type UB II submarine , there were some differences between the two designs . The Austro - Hungarian boats were slightly heavier than their German counterparts , by only while surfaced , but by while submerged . The UB II boats were shorter by about in length , but nearly identical in beam and draft . Both types of submarines were rated at the same on the surface , but the Austro - Hungarian boats were reported as over faster underwater even though the electric motors of the two classes had comparable power output . The German boats were more typically more heavily armed than their Austro - Hungarian cousins , and featured two larger torpedo tubes — vs . — and many sported a larger deck gun — vs . . Construction . With the plans purchased , the Austro - Hungarian Navy began the intricate political negotiations to assign the six boats — to be designated " U - 27 " to " U - 32 " — between Austrian and Hungarian firms . Of the initial order of six boats , two were allocated to the Austrian firm of Cantiere Navale Triestino ( CNT ) operating out of the Pola Navy Yard , and the balance to the Hungarian firm of Ganz Danubius in Fiume . The Navy ordered the first six boats of the class on 12 October 1915 . The first six boats were all laid down between late 1915 and early 1916 . Later in 1916 , the seventh boat of the class , , was laid down , after having been presented to the Navy as a gift by the " Österreichischen Flottenverein " , and an eighth , , as a replacement for , which had been lost in May . The seventh and eighth boats were constructed by CNT at the Pola Navy Yard . Shortages of labor and materials plagued subcontractors and , consequently , the delivery dates for the boats were not met . However , the first six boats had all entered service by the middle of 1917 . The first of the class to be launched was on 19 October 1916 , followed closely behind by three days later . The final boat launched was " U - 41 " on 11 November 1917 . The " U - 27 " class boats were the last domestically built submarines completed for the Austro - Hungarian Navy . Service career . All the boats of the " U - 27 " class , the most numerous of all the Austro - Hungarian submarine classes , saw active service , and all but one boat had wartime successes ; sank no ships during her career , and disappeared after the end of March 1917 , the only boat of the class to be lost during the war . and " U - 41 " also had little success , each credited with sinking a single ship . At the other end of the spectrum , " U - 27 " , the lead boat of the class , sank the largest number of ships , 33 , and sank the greatest amount of tonnage , . At the end of the war , " U - 27 " and were surrendered at Pola , while " U - 28 " and " U - 40 " were surrendered at Venice . All four of these boats were ceded to Italy as war reparations and were scrapped by 1920 . " U - 29 " , " U - 31 " , and " U - 41 " were half of the six submarines at Cattaro , and were all awarded to France . The boats were towed from Cattaro to Bizerta , but " U - 29 " foundered en route ; " U - 31 " , " U - 41 " , and the others were scrapped within twelve months of their arrival there . Class members . SM " U - 27 " . " U - 27 " , the lead boat of the class , was built by the Austrian firm of Cantiere Navale Triestino ( CNT ) at the Pola Navy Yard and launched on 19 October 1916 . She was commissioned on 24 February 1917 . During the war , she sank the British destroyer , damaged the Japanese destroyer " Sakaki " , and sank or captured 34 other ships totaling . " U - 27 " was surrendered at Pola at war ' s end and handed over to Italy as a war reparation in 1919 and was broken up the following year . " Conway ' s All the World ' s Fighting Ships , 1906 – 1921 " calls " U - 27 " Austria - Hungary ' s " most successful submarine " . SM " U - 28 " . " U - 28 " was built by CNT at the Pola Navy Yard and launched on 8 January 1917 . The boat was commissioned on 26 June 1917 . Under the command of Zdenko Hudeček , " U - 28 " sank ten ships totaling and damaged another . She was surrendered to the Italians at Venice in 1919 and scrapped in 1920 . SM " U - 29 " . " U - 29 " was built by the Hungarian firm of Ganz Danubius at Fiume and launched on 21 October 1916 . She was commissioned on 21 January 1917 , the first of the class to be commissioned . Under commander Leo Prásil , " U - 29 " sank three British steamers ( ) and damaged the British protected cruiser . " U - 29 " was at Cattaro at the end of the war and awarded to France as war reparation in 1920 , but foundered while under tow to Bizerta for scrapping . SM " U - 30 " . " U - 30 " was built by Danubius at Fiume , launched on 27 December 1916 , and commissioned on 17 February 1917 . The boat , under the command of " Linienschiffsleutnant " Friedrich Fähndrich , sailed from Cattaro on 31 March 1917 and was never heard from again . " U - 30 " sank no ships during her brief career . SM " U - 31 " . " U - 31 " was built by Danubius at Fiume and launched on 28 March 1917 . She was commissioned on 24 April 1917 . In addition to damaging the British light cruiser in October 1918 , during the battle of Durazzo . " U - 31 " sank one other ship , an Italian vessel of . She was scrapped in Bizerta after she was awarded to France in 1920 . SM " U - 32 " . " U - 32 " was built by Danubius at Fiume and launched on 11 May 1917 . The boat was commissioned on 29 June 1917 . " U - 32 " hit five ships of , sinking four and damaging one . At Pola at war ' s end , the boat was handed over to Italy and scrapped in 1920 . SM " U - 40 " . " U - 40 " was ordered after the funds to purchase the boat were presented by the " Östereichischen Flottenverein " as a gift to the Austro - Hungarian Navy . She was built by CNT at the Pola Navy Yard , launched on 21 April 1917 . and commissioned on 4 August 1917 . During the war , " U - 40 " sank two ships and damaged two others , hitting a total of Commonwealth shipping . The Italian destroyer " Ardea " claimed to have sunk " U - 40 " in a depth charge attack on 26 April 1918 , but the boat was surrendered to Italy at Venice in 1919 and broken up . SM " U - 41 " . " U - 41 " was ordered as a replacement for which had been sunk in May 1916 . She was built by CNT at the Pola Navy Yard and launched on 11 November 1917 . During construction , " U - 41 " was lengthened about to accommodate the diesel engines on hand that were to have been installed in " U - 6 " . " U - 41 " was commissioned on 19 February 1918 , the last boat of the class , and the last Austro - Hungarian boat completed and commissioned into the Austro - Hungarian Navy . " U - 41 " sank a single French steamer of during her short wartime career , and was at Cattaro at war ' s end . She was ceded to France in 1920 and towed to Bizerta , where she was scrapped within the year .