SM UB - 43 SM " UB - 43 was a Type UB II submarine or U - boat for the German Imperial Navy ( ) during World War I . " UB - 43 " was sold to the Austro - Hungarian Navy ( ) during the war . In Austro - Hungarian service the " B " was dropped from her name and she was known as SM " U - 43 or U - XLIII as the lead boat of the Austro - Hungarian " U - 43 " class . " UB - 43 " was ordered in July 1915 and was laid down at the AG Weser shipyard in Bremen in September . " UB - 43 " was a little more than in length and displaced between , depending on whether surfaced or submerged . She was equipped to carry a complement of four torpedoes for her two bow torpedo tube s and had an deck gun . As part of a group of six submarines selected for Mediterranean service , " UB - 43 " was broken into railcar sized components and shipped to Pola where she was assembled and launched in early April 1916 , and commissioned later in the month . Over the next year the U - boat sank twenty - two ships , which included the Peninsular and Oriental liner . " UB - 43 " also damaged the British cruiser . The German Imperial Navy was having difficulties filling submarine crews with trained men and offered to sell " UB - 43 " and a sister boat , , to the Austro - Hungarian Navy . After the terms were agreed to in June 1917 , both boats were handed over at Pola . When commissioned into the Austro - Hungarian Navy , the " B " in her designation was dropped so that she became " U - 43 " or " U - XLIII " . She damaged one Italian steamer in limited Austro - Hungarian service through the end of the war . " U - 43 " was ceded to France as a war reparation in 1920 and broken at Bizerta that same year . Design and construction . The German UB II design improved upon the design of the UB I boats , which had been ordered in September 1914 . In service , the UB I boats were found to be too small and too slow . A major problem was that , because they had a single propeller shaft / engine combo , if either component failed , the U - boat became almost totally disabled . To rectify this flaw , the UB II boats featured twin propeller shafts and twin engines ( one shaft for each engine ) , which also increased the U - boat ' s top speed . The new design also included more powerful batteries , larger torpedo tubes , and a deck gun . As a UB II boat , " U - 43 " could also carry twice the torpedo load of her UB I counterparts , and nearly ten times as much fuel . To accommodate all of these changes the boats ' had larger hulls , and surface and submerged displacements more than twice those of the UB I boats . The Imperial German Navy ordered " UB - 43 " from AG Weser on 31 July 1915 as one of a series of six UB II boats ( numbered from to ) . " UB - 43 " was long and abeam . She had a single hull with saddle tank s and had a draft of when surfaced . She displaced while submerged but only on the surface . The submarine was equipped with twin diesel engines and twin electric motors — for surfaced and submerged running , respectively — that drove twin propeller shafts . " UB - 43 " had a surface speed of up to and could go as fast as while underwater . The U - boat could carry up to of diesel fuel , giving her a range of 6 , 940 nautical miles at 5 knots ( 12 , 850 km at 9 . 3 km / h ) . Her electric motors and batteries provided a range of 45 nautical miles at 4 knots ( 83 km at 7 . 4 km / h ) while submerged . " UB - 43 " was equipped with two bow torpedo tube s and could carry four torpedo es . The U - boat was also armed with an 88 mm / 26 ( 3 . 5 in ) deck gun and an machine gun . " UB - 43 " was laid down by AG Weser at its Bremen shipyard on 3 September 1915 . As one of six U - boats selected for service in the Mediterranean while under construction , " UB - 43 " was broken into railcar - sized components and shipped overland to the Austro - Hungarian port of Pola . Shipyard workers from Weser assembled the boat and her five sisters at Pola , where she was launched on 8 April . German Imperial Navy career . SM " UB - 43 " was commissioned into the German Imperial Navy on 24 April 1916 under the command of " Oberleutnant zur See " Dietrich Niebuhr ; " UB - 43 " was the only U - boat command for the 27 - year - old officer . " UB - 43 " was assigned to the Navy ' s Pola Flotilla ( ) in which she remained throughout her German career . Although the flotilla was based in Pola , the site of the main Austro - Hungarian Navy base , boats of the flotilla operated out of the Austro - Hungarian base at Cattaro which was located farther south and closer to the Mediterranean . German U - boats typically returned to Pola only for repairs . Under Niebuhr ' s command , " UB - 43 " had no success , and he was replaced by " Kapitänleutnant " Hans von Mellenthin on 29 August . After two weeks under von Mellenthin ' s command , " UB - 43 " sank her first ship . While east of Malta , the British steamer " Italiana " with her cargo of hay destined for Salonica was torpedoed and sunk . Three days later , and some closer to Malta , von Mellenthin sank a pair of British steamers . " Dewa " was in ballast headed for Port Said when attacked by " UB - 43 " ; three of the steamer ' s crew lost their lives in the attack . " Lord Tredegar " was carrying a general cargo when she was sent down with the loss of four men . " The Wall Street Journal " reported that the sinking of " Lord Tredegar " resulted in a loss of $ 1 , 000 , 000 for her American insurer . In October , von Mellenthin and " UB - 43 " sank an additional two ships . On 10 October , the British tanker " Elax " , carrying fuel oil from Rangoon was sunk off Cape Matapan without casualties . Three days later , two men were killed when " UB - 43 " torpedoed and sank their ship , the British steamer " Welsh Prince " , of . On 18 November , the British Admiralty , released a report that listed all of " UB - 43 " s first five victims as evidence of German wrongdoing . According to the British report , " Italiana " , " Dewa " , " Lord Tredegar " , and " Elax " — four of the twenty - two ships listed — had all been torpedoed without warning . This type of attack was counter to German pledges to adhere cruiser warfare , which required that ships be allowed time for the crews to escape before any attack could commence . " UB - 43 " s fifth victim , " Welsh Prince " , was on another list of 107 British ships sunk whose lifeboats had been fired upon by German submarines . In the meantime , " UB - 43 " had continued sinking British ships , sending down five in a nine - day span in early November . " Statesman " , a 6 , 153 - ton steamer carrying a general cargo , was first on 3 November ; six crewmen were killed when the ship went down east of Malta . The following day , the 3 , 937 - ton " Clan Leslie " and the 5 , 398 - ton " Huntsvale " were sunk in the same area . " Clan Leslie " was carrying a general cargo from Bombay when sunk with three casualties . Seven were killed when " Huntsvale " , traveling in ballast for Algiers , was sunk . On 6 November , " UB - 43 " torpedoed the Peninsular and Oriental liner off Cape Matapan . According to contemporary news accounts , gunners on " Arabia " fired upon " UB - 43 " after the liner was torpedoed , but recorded no hits . All 437 passengers aboard the steamer , en route from Sydney to London when attacked , were rescued after an hour in the water . The liner went down 90 minutes after the torpedo struck . Eleven died in the attack , including two of " Arabia " s engineers killed in the initial blast of the torpedo . Six days after " Arabia " s sinking , " UB - 43 " sank the 3 , 383 - ton British steamer " Kapunda " east of Malta . " Kapunda " s loss brought the U - boat ' s November tally to 26 , 774 gross register tons , which accounted for more than 15 % of the November tally for all German U - boats in the Mediterranean . " UB - 43 " and von Mellenthin sank three more British steamers in December : " Bretwalda " on the 13th , and " Russian " and " Westminster " on the 14th . " Bretwalda " — which had escaped destruction from a mine laid by in August 1915 — and her cargo of jute were sent down from Malta . " Russian " , at 8 , 825 tons , was the largest ship sunk by " UB - 43 " ; the horse transport ship was sailing in ballast from Salonica when she went down with 28 of her crewmen . After " UB - 43 " torpedoed " Westminster " , the U - boat shelled the survivors in their lifeboats , according to authors R . H . Gibson and Maurice Prendergast . Fifteen men from " Westminster " died in the sinking . " UB - 43 " sank no ships over the next eight weeks . Author Paul Halpern reports that the majority of the German U - boats in the Mediterranean fleet were undergoing repairs and refits at Pola and Cattaro during January . Although no specific mention is made of repairs done on " UB - 43 " , the U - boat ' s inactivity in this period may be for that reason . Unrestricted submarine warfare . On 1 February 1917 , Kaiser Wilhelm II personally approved a resumption of unrestricted submarine warfare in order to try to force the British to make peace . The new rules of engagement specified that no ship was to be left afloat , although British reports for several of " UB - 43 " s victims suggest that von Mellenthin was already operating in this manner . Under these new rules of engagement , " UB - 43 " first sank the Greek steamer " Miaoulis " from Benghazi on 24 February , while she was carrying cottonseed to London . Two days later , the turret hull steamer " Clan Farquhar " , carrying cotton and coal for London , was torpedoed and sunk . After the attack , which killed 49 of her crew , the ship ' s second engineer was taken captive by von Mellenthin . On the 27th , " Brodmore " and her cargo of frozen meat from Majunga were sunk off Libya ( and her master taken prisoner ) , and on the 28th the Japanese steamer " Shinsei Maru " was sunk nearby . It was nearly a month later before von Mellenthin and " UB - 43 " sank their next target . On 26 March , the British steamer " Ledbury " , carrying wheat from Karachi , was sunk from Benghazi . Eight days later , " Vasilefs Constantinos " , a Greek steamer of , was sunk in the Ionian Sea ; the " Constantinos " was the last ship sunk by " UB - 43 " under von Mellenthin ' s command . On 9 April , von Mellenthin was succeeded by " Oblt . " Horst Obermüller , a 26 - year - old first time U - boat commander . Under von Mellenthin ' s command , " UB - 43 " had sunk of merchant shipping . On 1 May , Obermüller sank the American - owned ( but British - flagged ) tanker " British Sun " carrying a load of fuel oil . According to a report in " The New York Times " , the 5 , 565 - ton vessel , valued at $ 2 , 500 , 000 , was " one of the finest " tankers . The collier " Repton " was sent down off Cape Matapan six days later ; three of the British steamer ' s crewmen died in the attack . Later in the month , the Greek steamer " Dorothy " and her cargo of wheat from Karachi were sunk from Cap D ' Armi . " UB - 43 " s final attack of note was upon the cruiser , torpedoed east of Malta . " Grafton " was damaged but suffered no casualties . The - displacement British ship was brought safely into port at Malta . On 21 July , " UB - 43 " was decommission ed at Pola and handed over to the Austro - Hungarian Navy . In her German Imperial Navy career of fourteen months , " UB - 43 " sank twenty - two merchant ships totaling , and damaged one warship with a displacement of . Austro - Hungarian Navy service . In November 1916 , the German Imperial Navy , having a hard time finding trained submarine crews , inquired to find out if its ally Austria - Hungary was interested in purchasing some of its Mediterranean submarines . A general agreement led to protracted negotiations , which stalled over the outflow of Austro - Hungarian gold reserves to Germany . But , with all of the details worked out , the two parties agreed on the sale of " UB - 43 " and sister ship to Austria - Hungary in June 1917 . When handed over by the Germans on 21 July , " UB - 43 " was in a " worn out condition " . Despite the rough condition of the boat , the U - boat was commissioned into the Austro - Hungarian Navy on 30 July 1917 as SM " U - 43 " , dropping the " B " from her former designation . " Linienschiffsleutnant " Friedrich Schlosser was installed as the new commander of the U - boat , which remained at Pola for the next three months undergoing repairs . Departing that port on 1 November , " U - 43 " made way to Cattaro , and then went out on patrol . Schlosser torpedoed the Italian steamer " Orione " on 16 November , but the Italian ship did not sink ; she was towed to safety in Taranto . On 30 November , a leak on " U - 43 " partially flooded the boat and caused her to sink to a depth of before she was bought under control and raised to the surface . The flooding damaged the U - boat ' s electrical systems , preventing her from submerging on her return to port for repairs . An unidentified submarine launched a torpedo at the surfaced " U - 43 " , but the torpedo ' s aim was off and it passed harmlessly in front of the bow . The boat made port at Cattaro on 1 December and at Pola on 6 December for two months of repairs . During " U - 43 " s time under repair , Schlosser was reassigned to command , and " Linienschiffsleutnant " Eugen Hornyák Edler von Horn was named to take his place aboard " U - 43 " on 18 January 1918 . Under von Horn , " U - 43 " patrolled off Cattaro , having to crash dive at least once to escape attack from enemy torpedo boats . On 17 March , while returning to Cattaro from patrol , the crew of the Austro - Hungarian destroyer mistook " U - 43 " for an enemy submarine and rammed her , damaging the diving plane s . " U - 43 " sailed for Fiume for three months of repairs . The U - boat returned to action in June and patrolled off Montenegro , Durazzo , and Cattaro for the next five months . On 13 June , " U - 43 " was slightly damaged in an air raid on Cattaro and , on 5 September , had to crash dive to avoid another air attack while off Cattaro . On 20 September , the boat rendezvoused with " U - 47 " and received a French prisoner of war . The prisoner was the only survivor of the French submarine , which " U - 47 " had torpedoed the night before . At the end of the war , " U - 43 " was at Cattaro . In her Austro - Hungarian Navy career , " U - 43 " damaged a single merchant ships of 4 , 016 gross register tons . " U - 43 " was ceded to France as a war reparation in 1920 , towed to Bizerta , and broken up there within a year . Ships sunk or damaged . As the German " UB - 43 " . < nowiki > * < / nowiki > damaged but not sunk As the Austro - Hungarian " U - 43 " . < nowiki > * < / nowiki > damaged but not sunk