 The boat was commissioned into the Austro-Hungarian Navy in July 1910, and served as a training boat—sometimes making as many as ten cruises a month—through the beginning of the First World War in 1914.The submarine had only one wartime success, which was sinking a French destroyer in March 1916.Later that year, in May, "U-6" became entangled in anti-submarine netting deployed as part of the Otranto Barrage.