The Battle of the Atlantic new born

Germany in 1941. War in Europe for two years. The Nazis at the height of their power. Since the beginning of the war, there has been a frontline in the west where the traces of horrible fights disappear on the spot:The Battle of the Atlantic. England, traditionally the leading naval power worldwide was to be cut off from all supplies by a blockade while the balance of power is not in favor of the German Kriegsmarine. Their commander-in-chief complains that "the war was five years early." That a victory seems achievable at the beginning is the result of a weapon that was only known in Germany at the height of perfection and drill: submarines.