addition, four of the German Type UB Is assigned to the Pola Flotilla based at the Austro-Hungarian Navy's main naval base at Pola were assigned Austro-Hungarian designations. (as U-9) (as U-7) (as U-8) (as U-26) These four boats remained under commission in the German Imperial Navy, retained German crews and commanders, and received orders from the German flotilla commander at Pola. Bulgarian Navy Germany and Bulgaria negotiated the purchase of two UB I boats for the Bulgarian Navy, and , in 1916. Two crews of Bulgarian sailors were sent to Kiel for training. Before the purchase could be completed, UB-7 was sunk, leaving only one boat for Bulgaria. On 25 May 1916, UB-8 was officially transferred to Bulgaria for the remainder of the war. Podvodnik No. 18 (the former German UB-8) Service records Key Notes Footnotes Citations References 01 Type UB I Type UB I 1914 introductions 1914 in Germany