Escorting slow convoy ONS 7 bound for Halifax , Canada , she sank the German submarine U-657 off Cape Farewell , Greenland on the night of 17 May .
Swale was to have better fortunes two months later .
Escorting slow convoy ONS 7 bound for Halifax , Canada , she sank the German submarine U-657 off Cape Farewell , Greenland on the night of 17 May .
Swale was to have better fortunes two months later .