UB-8 was transferred to the Bulgarian Navy in May 1916, and UB-7 disappeared in the Black Sea in October 1916, leaving UB-14 as the sole remaining German Type UB I in the flotilla; she was surrendered at Sevastopol in November 1918 to French armies stationed there during the Russian Civil War. Austro-Hungarian Navy UB-1 and the still incomplete UB-15 were sold to the Austria-Hungary in February 1915; both were dismantled and shipped to Pola in May. After one cruise under the German flag, each boat was commissioned into the Austro-Hungarian Navy. The pair—renamed U-10 and U-11, respectively—were joined by U-15, U-16, and U-17 in October. Known as the U-10 or the Okarina () class as a part of the Austro-Hungarian Navy, the five boats operated primarily in the Adriatic in patrols off Italy and Albania. U-10 (ex UB-1) hit a mine in July 1918 and was beached, but had not been repaired by the end of the war. U-16 was sunk after she torpedoed an Italian destroyer in October 1916, and the remaining three (and the unrepaired U-10) were ceded to Italy at the end of the war. Bulgarian Navy After UB-8 was transferred to the Bulgarian Navy in May 1916, she was renamed Podvodnik No. 18 (in Cyrillic: Подводник No. 18). She was Bulgaria's first submarine, and was engaged primarily in coastal defense duties off Bulgaria's main Black Sea port of Varna. Podvodnik No. 18 survived the war and was ceded to France after the Treaty of Neuilly-sur-Seine. List of Type UB I submarines A total of 20 Type UB I submarines were built, 17 for the German Imperial Navy and three for the Austro-Hungarian Navy. Two of the German submarines—UB-1 and UB-15—were sold to Austria-Hungary and commissioned into the Austro-Hungarian Navy as U-10 and U-11, respectively. Those two and a further three built by AG Weser comprised the virtually identical U-10 class for the Austro-Hungarian Navy. Another of the German submarines, UB-8, was sold to Bulgaria in May 1916, becoming Podvodnik No. 18. German Imperial Navy (became the Austro-Hungarian U-10, July 1915) (became the Bulgarian Podvodnik No. 18, May 1916) (became the Austro-Hungarian U-11, June 1915) Austro-Hungarian Navy In the Austro-Hungarian Navy the Type UB I boats were known as the U-10 class, which consisted of two former German Type UB I boats and three built specifically for Austria-Hungary. (the former German UB-1) (the former German UB-15) In