. "She operated as part of the Pola Flotilla based in Cattaro. UB-52 was sunk on 23 May 1918 at by HMS H4, all hands lost."@en . . . . "SM UB-52"@en . . . . . . . . . . "--05-20"^^ . . . . "300"^^ . . . . "She operated as part of the Pola Flotilla based in Cattaro. UB-52 was sunk on 23 May 1918 at by HMS H4, all hands lost."@en . . . . . . . . . "UB-148 at sea, a U-boat similar to UB-52."@en .