 Germany began its second submarine offensive against shipping in February 1916 , the month U @-@ 70 had joined the 4th Flotilla . As in the first submarine offensive , U @-@ boats were sent independently around Scotland to patrol the Irish Sea and the western entrance to the English Channel . U @-@ 70 sank her first ship on 16 March , when she dispatched the British sailing vessel Willie 60 nautical miles ( 110 km ; 69 mi ) northwest by west of Fastnet Rock . The same day she also damaged the British cargo ship Berwindale , en route to Avonmouth with a load of wheat from Galveston , Texas . Throughout the rest of March and into early April , U @-@ 70 sank an additional five ships of 14 @,@ 557 gross register tons ( GRT ) ; the largest being the British cargo vessel Eagle Point , carrying a load of hay and oats from Saint John , New Brunswick , torpedoed and sunk on 28 March . Near the end of April 1916 , Admiral Reinhard Scheer , the new commander @-@ in @-@ chief of the High Seas Fleet ( under which U @-@ 70 's 4th Flotilla operated ) , called off the merchant shipping offensive and ordered all boats at sea to return , and all boats in port to remain there . 
