The United States of America took a huge blow at Pearl Harbor in 1941, which prompted them join the war alongside the British. Before that event, America was already delivering economic help and acted as an observer party of the Allies, leasing ships and approving loans to help the war effort.
The Germans adopted the total war doctrine which meant that they waged war against the standard rules of warfare. This led to the declaration of the unrestricted submarine war on the Allied merchant and transport ships which were assigned to deliver supplies and weapons to the British Isles.
German submarines in the period 1940-1941, managed to gain significant success in the Atlantic theater of the War against the British ships. This was due to lack of radar equipment and high-frequency finding devices of the Allied vessels. The ships were equipped mostly with sonars that could detect submerged submarines, but were helpless against surface raids that the Germans often practiced at night.
Black submarines were practically invisible during night-time which provoked paranoia among the crewman stationed on the ships. The Germans called this period “The Happy Time”, for they could sink ships with little or no casualties on their side.
One day after the events of Pearl Harbor, the Germans declared war on the United States. Since the Atlantic Ocean separated the United States from the battlefields of Europe, the sea became the stage of the initial conflict between the new enemies.
Grand Admiral of the Reich, Karl Donitz devised a plan in December 1941, in which he set out to harass the ships moving by the coastal line of the North American continent. He called it Operation Drumbeat. The Germans sent three of their Type IX long-range U-boats to the coastal waters of the US. They were assigned to stay submerged during the day and ambush merchant ships during night. The British intelligence picked up movement from the port of Lorient in France and informed the Canadian and American Navies.
The British experience in the submarine wars of the Atlantic during the first two years of World War Two suggested the use of some precautionary measures. The British Royal Navy noted that all coastal cities should stay in the state of blackout during night-time, that all ships should travel in convoys and that all navigational markers and lighthouses should be put out of commission, as they could help the enemy more than they would help the Allies. In addition they strongly advised that all available sea and air forces should be put to use in patrolling the coast, thus restricting the U-boats freedom of movement.
None of these recommendations were taken seriously by the American coastal defense in the first several months of the US official involvement in the war. The US Eastern Sea Frontier Command believed that the ships are safer if they travel alone, as then they prove to be poor targets for the Germans, who would be more interested in an entire convoy. The blackout order was not given, but was rather only advised to coastal boardwalk communities, not including significant tourist sites such as New York and other large cities of the Eastern Coast.
The Eastern Sea Frontier defense was poorly armed for anti-submarine combat. At their disposal were vintage gunboats dating back to 1905, some 1919 vintage patrol boats, four converted yachts and seven Coast Guard cutters which were the only vessels capable of defending convoys from a U-boat attack.