The next patrol began on 25 October and ended on 26 November 1941 in Saint-Nazaire. This was also Koitschka's last war patrol as first watch officer on "U-552". On "U-552"s sixth war patrol into the North Atlantic, east of Grand Banks of Newfoundland, Topp sank the destroyer on 31 October 1941, the first United States Navy warship to be lost in World War II while it escorted Convoy HX 156. The torpedo struck a forward magazine, blowing the ship apart. All of her officers and over 100 of the crew went down with the ship. The destruction of the "Reuben James" facilitated a worsening of already rapidly deteriorating diplomatic relations between Nazi Germany and the still nominally neutral United States of America. President Franklin D. Roosevelt used the incident to shift public opinion toward a confrontational stance with the European Axis powers. Support for the Neutrality Acts of the 1930s gradually eroded. On 13 November 1941 amendments to the act allowed for the arming of US merchant ships, their operation in the war zone, and active assistance to the British Empire to increase the tonnage available to it. Hitler and the Nazi leadership wished to keep the US neutral and the order to minimise contact at sea remained in force, at least until Operation Barbarossa had destroyed the Soviet Union. Roosevelt did not publicly mention the destroyer was escorting a British convoy, was not flying the Ensign of the United States, and was in the process of dropping depth charges on another U-boat when it was engaged and sunk.