SM UB - 45 SM " UB - 45 " was a Type UB II submarine or U - boat built for and operated by the German Imperial Navy ( ) during World War I . " UB - 45 " operated in the Mediterranean and the Black Seas , and was sunk by a mine in November 1916 . " UB - 45 " was ordered in July 1915 and was laid down at the AG Weser shipyard in Bremen in September . " UB - 45 " 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 - 45 " was broken into railcar - sized components and shipped to Pola where she was assembled and then launched and commissioned in May 1916 . In five patrols in her six - month career , " UB - 45 " sank four ships of . In early November 1916 , " UB - 45 " was departing from the base at Varna , Bulgaria , when the U - boat struck a mine and sank rapidly . Fifteen of the twenty men on board were killed in the attack ; one of the five crewmen rescued from " UB - 45 " later died from his injuries . " UB - 45 " s wreck was located and raised by the Bulgarian Navy in the 1930s with an eye toward rebuilding the submarine . Engineers from AG Weser determined that restoration of the submarine was feasible , but this was never accomplished . Remains recovered from the wreck were buried in Varna after a funeral procession through town in November 1938 . 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 - 45 " could also carry twice the torpedo load of her UB I counterparts , and nearly ten times as much fuel . To contain all of these changes the hull was larger , and the surface and submerged displacement was more than double that of the UB I boats . The German Imperial Navy ordered " UB - 45 " from AG Weser on 31 July 1915 as one of a series of six UB II boats ( numbered from to ) . " UB - 45 " 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 - 45 " 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 - 45 " was equipped with two bow torpedo tube s and could carry four torpedo es . The U - boat was also armed with a 8 . 8 cm KL / 40 ( 3 . 5 in ) deck gun . " UB - 45 " 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 - 45 " 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 12 May 1916 . Service career . SM " UB - 45 " was commissioned into the German Imperial Navy on 26 May 1916 under the command of " Oberleutnant zur See " Karl Palis . " UB - 45 " , Palis ' second U - boat command , was assigned to the Navy ' s Pola Flotilla ( ) . 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 . In mid - July , " UB - 45 " s first success occurred when in three days she sank two steamers . The first , " Virginia " , was sunk on the 16th while carrying salt destined for Calcutta . Two men on board the 4 , 279 - ton British ship were lost when she went down off Cape Matapan . Two days later , the French ship " Ville de Rouen " was sunk southwest of Cape Matapan . The 4 , 721 - ton " Ville de Rouen " would be " UB - 45 " ' s largest victim . Germany ' s conquest of Romania provided the German Imperial Navy with sufficient fuel oil for submarines to operate in the Black Sea . " UB - 45 " and three of her sister ships in the Pola Flotilla were ordered to Constantinople and , en route , had to navigate through the Dardanelles , which had been heavily mined by the Allies in the middle of 1916 . " UB - 45 " joined the Constantinople Flotilla ( ) on 12 August . The German submarines in the Black Sea accomplished little , sinking only six ships between August and the end of the year ; " UB - 45 " accounted for two of these while in the Black Sea . On 31 August , " UB - 45 " sank the 2 , 660 - ton Italian steamer " Tevere " off Poti . " Tevere " had been requisitioned by the Imperial Russian Navy and was in use as a transport ship at the time . Two days later , the U - boat torpedoed the 3 , 701 - ton " Gioconda " , another Russian transport , off Trebizond . " Gioconda " was the last ship sunk by " UB - 45 " . At 14 : 30 on 6 November , " UB - 45 " was departing Varna , Bulgaria , under escort by the Bulgarian torpedo boat " Strogi " that had cleared a path through Russian mine s . At what was thought to be the edge of the minefield , " UB - 45 " swung around " Strogi " s port side directly into a second minefield that had been laid by Russian forces the night before . A Hertz horn mine exploded between " UB - 45 " s control room and engine room with enough force to break the boat in half . " UB - 45 " sank so rapidly that the only survivors were three men on the conning tower and two on deck , all of whom were injured ; the other fifteen men on board perished in the attack . One of the survivors died from the severity of his wounds the following day . In 1932 , the Bulgarian Navy conceived a plan to search for the wreck of " UB - 45 " with the intent of raising it for restoration as a training vessel , or , at the very least , to recover the sunken U - boat ' s deck gun . An additional consideration was the recovery of the remains of " UB - 45 " s crew . On 19 July 1934 , after a two - year search , Bulgarian minesweeper s discovered the location of the wreck , which was resting at position , near the then Bulgarian – Romanian border . " UB - 45 " s wreck was raised in an operation that cost several times less than the cost of a new 8 . 8 - centimeter gun . The remains recovered were buried on 26 February 1936 in a Varna cemetery , after a procession through the town . Engineers from AG Weser , " UB - 45 " s German builder , inspected the hulk and determined that repair of the wreck was feasible . A restoration of the submarine to operating condition , as either a training vessel or a military , would cost 21 million leva ( about US $ 250 , 000 in 1936 dollars ) , significantly less than the 56 to 65 million leva ( $ 680 , 000 to $ 790 , 000 ) that a comparable new submarine would cost . Ultimately , the Bulgarian Navy opted to order new submarines from Germany rather than repair " UB - 45 " . " UB - 45 " s deck gun was reused , however , and one of the U - boat ' s diesel engines was restored to operating condition and used on the training ship " Assen " .