 In April 1917 , UB @-@ 42 was operating in the Mediterranean when she made attacks on three ships . On 14 April , Wernicke torpedoed the British Acacia @-@ class sloop HMS Veronica 45 nautical miles ( 83 km ; 52 mi ) off Alexandria , damaging the 1 @,@ 200 t vessel . Two days later , UB @-@ 42 sank the 86 @-@ ton Egyptian sailing ship off Gaza and , a week after that , sank a 15 @-@ ton Italian sailing vessel , Boro , east of Rhodes in the Aegean Sea . 
