This convoy must not get through—U-boats pursue, attack and sink. This was the signal that Admiral Dnitz sent to the commanders of the 21 U-boats of the Markgraf wolf-pack on September 9, 1941 just before the United States entered the war. Sixty-three merchant ships were strung out in 12 columns abreast, covering 25 miles of inhospitable ocean. They set sail from Nova Scotia at a time when the German U-boats were sinking more than one hundred ships a month and the US Navy could do nothing but stand-by and watch—at least officially. ...The American ships had served their purpose, for although they had taken great pains not to be associated with SC42's official escort, the mere presence of these modern, powerful men-of-war had contributed to the withdrawal of the U-boats. The battle lasted for seven days and covered 1,200 miles of ocean.