 UB @-@ 50 started out her third patrol by finding and sinking the 9 GRT Italian sailboat S. Giuseppe B. off the coast of Africa . She sank the 8 @,@ 293 GRT British steamer City of Lucknow two days later 50 nautical miles ( 93 km ; 58 mi ) northeast of the <unk> Rocks . On Christmas Day , 1917 , UB @-@ 50 sank the Sant ’ Antonio , an 843 GRT Italian sailing vessel , by gunfire near Bizerte . On New Year 's Day , 1918 , the Egyptian Transport , a 4 @,@ 648 GRT British steamer , was damaged during an attack by UB @-@ 50 , which killed five men . It was later beached but refloated . Two days later , the <unk> , a 4 @,@ 253 GRT British steamer carrying coal , was sunk by UB @-@ 50 , which also sunk the <unk> , a 3 @,@ 649 GRT British steamer also carrying coal later that day . Four days later , UB @-@ 50 torpedoed the Arab , a 4 @,@ 191 GRT British steamer coal off the coast of Cape Serrat , killing 21 . 
