SM UB-52 [SEP] vessel class
SM UB-52
SM "UB-52" was a German Type UB III submarine or U-boat in the German Imperial Navy () during World War I. She was commissioned into the Pola Flotilla of the German Imperial Navy on 9 August 1917 as SM "UB-52".
She operated as part of the Pola Flotilla based in Cattaro. "UB-52" was sunk by torpedo on 23 May 1918 at by the British submarine enforcing the Otranto Barrage at the southern end of the Adriatic, with all hands lost. 
Construction.
with a deck-mounted machine gun. "UB-13" was broken into sections and shipped by rail to Antwerp for reassembly. She was launched in March 1915 and commissioned as SM "UB-13" in April.
"UB-13" spent her entire career in the Flanders Flotilla and sank 11 merchant ships, about half of them British fishing vessels. In March 1916, "UB-13" was responsible for sinking the Dutch ocean liner , raising the ire of the Dutch public. "Tubantia" was the largest neutral vessel sunk during