 The fall , on the other hand , brought Wainwright increased activity . After spending the first two weeks of September in repairs at Birkenhead , near Liverpool , she departed the yard at Laird Basin at about 07 : 00 on the 14th to return to Queenstown . Three quarters of an hour into the afternoon watch , she received orders sending her to the scene of a submarine attack against an Allied merchantman some 15 nautical miles ( 28 km ) south @-@ southeast of Helvick Head , Ireland . Wainwright rang up full speed , made off for the reported location , and began a search for the U @-@ boat in conjunction with a British dirigible and other surface units . Near the end of the second dog watch , she sighted the submarine 's conning tower and bow about 6 nautical miles ( 11 km ) off . 
