SM U-10 (Austria-Hungary)

U-10 was a small, coastal submarine that displaced 127 tonnes (125 long tons) surfaced and 142 tonnes (140 long tons) submerged. She featured a single shaft, a single 60 bhp (45 kW) Daimler diesel engine for surface running, and a single 120 shp (89 kW) electric motor for submerged travel.[1] U-10 was capable of up to 6.5 knots (12.0 km/h; 7.5 mph) while surfaced and 5.5 knots (10.2 km/h; 6.3 mph) while submerged at a diving depth of up to 50 metres (160 ft).[6] She was designed for a crew of 17 officers and men.[1]

U-10 was equipped with two 45 cm (17.7 in) torpedo tubes located in the front and carried a complement of two torpedoes.[1] German Type UB I submarines were additionally equipped with a 8 mm (0.31 in) machine gun, but it is not clear from sources if U-10, as a former German boat, was either equipped with one or, if so, retained it in Austro-Hungarian service.[6] In October 1916, U-10's armament was supplemented with a 37-mm/23 (1.5 in) quick-firing (QF) gun. This gun was replaced by a 47 mm (1.9 in)/33 QF gun in November 1917.[1]

Construction of UB-1 was started on 1 November 1914 at Germaniawerft in Kiel. After her assembly was complete UB-1 was launched on 22 January 1915.[1]

After extended negotiations between Austria-Hungary and Germany, in March 1915 it was decided for Germany to supply five submarines of the UB I type. This model was familiar to the Austro-Hungarian Navy since the Imperial German Navy had reassembled UB3, UB 8, and UB 9 at the Pola Navy Yard. The first boat was bought on April 4, 1915, a "sample" UB 1 boat.[7] This submarine was shipped by rail in sections to Pola, where the sections were riveted together.[1] Though there is no record of how long it took for UB-1's parts to be assembled, a sister boat, UB-3, shipped from Germany in mid-April 1915, was assembled in about two weeks.[8]

SM UB-1 was commissioned into the German Imperial Navy under the command of Oberleutnant zur See Franz Wäger on 29 January.[2] An Austro-Hungarian Navy officer was assigned to the boat for piloting and training purposes. On 26 June 1915, UB-1 sank an Italian torpedo boat 5 PN in the Gulf of Venice.[3]

On 4 June 1915, after being disassembled into three sections and transported by rail to Pola for reassembling,[7] UB-1 was handed over to the Austro-Hungarian Navy and commissioned as U-10 under the command of Linienschiffsleutnant Karl Edler von Unczowski.[1]

British submarine H4 had an encounter with U-10 on 11 May 1917. While cruising off Pola, H4 came across U-10 and fired a spread of two torpedoes at the submarine. The torpedoes were aimed to be 5° apart at a distance of 365 metres (400 yd) which was apparently too wide, because the captain of H4 observed the torpedoes miss just ahead and just astern of U-10.[9]

On 9 July 1918, U-10 hit an Italian mine near Caorle in the northern Adriatic Sea at position 45°30′N 13°00′E,[10] 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 unfinished at war's end; all of the 13 crew personnel were saved.[11] U-10 was handed over to Italy as a war reparation and scrapped at Pola by 1920.[1] U-10 sank no ships in her Austro-Hungarian service.[4]