"This convoy must not get through -- U-boats pursue, attack and sink." This was the signal that Admiral Donitz sent to the commanders of the 21 U-boats of the Markgraf wolf-pack on 9 September 1941 just before the US 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 convoy's escort of one destroyer and three corvettes of the Royal Canadian Navy, all untried in combat, was hopelessly outclassed when the battle for SC42 commenced. The battle lasted for 7 days and covered 1200 miles of ocean.