 SM UB @-@ 50 was a German Type UB III submarine or U @-@ boat in the German Imperial Navy ( German : Kaiserliche Marine ) during World War I. The U @-@ boat was ordered on 20 May 1916 . She was commissioned into the Pola Flotilla of the German Imperial Navy on 12 July 1917 as SM UB @-@ 50 . 
