U-43-class submarine (Austria-Hungary)

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 the most urgent needs, In November 1916, Germany had inquired to find out if Austria-Hungary were interested in purchasing existing German submarines because Germany was having a hard time finding trained submarine crews. After protracted negotiations, which had stalled over the outflow of Austro-Hungarian gold reserves to Germany, an agreement to purchase two submarines—UB-43 and UB-47—was reached in June 1917. == Design ==

The UB II design The German UB II design of coastal submarines was a development from the design of the UB I boats, which had been originally ordered in September 1914. During their trials, the UB I boats were found to be too small and too slow, but in-service use revealed another problem. The UB I boats had a single propeller shaft/engine combo such that if either component failed, the U-boat became almost totally disabled. The UB II boats featured twin propeller shafts and twin engines (one shaft for each engine) which not only alleviated this problem, but also had the added benefit of increasing the top speed. The new design also included more powerful batteries, The UB II boats could also carry twice the torpedo load of their predecessors, and nearly ten times as much fuel. Like all of the UB II boats from different manufacturers and contract groups, the U-43 group had distinct specifications. This group displaced surfaced and submerged. and were long with a beam of and a draft of . == Construction ==

The six-boat group that included UB-43 and UB-47 was ordered in July 1915, and both boats had been laid down in early September. This group was selected by the German Admiralstab for deployment to the Mediterranean, but, unlike the smaller UB I boats, they could not as easily be transported overland by rail. Weser prepared the boats for rail shipment by cutting the boat sections longitudinally, and sent all the materials, along with German shipyard workers, to Pola, where the boats were reassembled. UB-43 was launched in early April 1916, while UB-47 followed in June. == Class members ==

SM U-43 UB-43 was ordered by the Imperial German Navy on 31 July 1915 and was laid down by AG Weser of Bremen on 3 September. In April 1917, von Mellenthin was replaced by Oberleutnant zur See Horst Obermüller who commanded the ship for the next three months, The submarine's successes while under German command were not matched under Austro-Hungarian; she damaged a single ship in November 1917 in her only successful attack. U-47 was surrendered to France as a war reparation in 1920 and was broken up at Bizerta. SM U-47 UB-47 was ordered by the Imperial German Navy on 31 July 1915 and was laid down at Bremen by AG Weser on 4 September. Steinbauer also damaged three ships with a combined gross register tonnage of 16,967. Under the command of Hans Hermann Wendlandt, who had replaced Steinbauer in April 1917, UB-47 sank an additional seven ships ( and 350 tons) through 21 July, at which time the ship was decommissioned and handed over to the Austro-Hungarian Navy. U-47s success under Austro-Hungarian command was less than that under the German flag; only three ships ( and 351 tons) were sunk through the end of the war. U-47 was surrendered to France as a war reparation in 1920 and was broken up at Bizerta. == Notes ==