The last American merchant ship sunk in the undeclared war was the unarmed SS Sagadahoc, which was stopped in the South Atlantic on December 3 by the submarine U-124. The German commander, deciding the ship carried contraband, ordered its 35-man crew into lifeboats. The Sagadahoc was then sunk. However, one sailor failed to leave the ship and went down with her. He was probably the last sailor to die in the unofficial war in the Atlantic.
The undeclared naval war between the United States and Germany was coming to an end. Four days after the Sagadahoc was sunk, the Japanese bombed Pearl Harbor. On December 11, 1941, Germany and Italy declared war on the United States.