On 18 December 1941, Adm Karl Doenitz dispatched five of his long range Type IX U-Boats from Lorient, France on Operation Paukenschlag or Operation Drumbeat. British Intelligence picked up on the departure and warned the Canadians and Americans that they were most likely heading to the Western Atlantic. They indeed were: each U-boat was stuffed with to capacity with food, fuel and torpedoes for an extended patrol off the US coast. Each had tour guides of the coasts of their respective patrol zones, many of which included harbor maps, and in many cases, military installations.
President Roosevelt established the Pan American Security Zone after Germany declared war on 11 December, and the Eastern Sea Frontier included the Atlantic coast. But the unfortunate rear admiral who pulled that duty had only seven coast guard cutters, four yachts, and a smattering of civilian sailing ships. In any case it didn’t matter: cargos ships traveled with their running lights on, there was no blackout along the coast, and no convoy system between American ports was adopted for months.
The first ship sunk off the American coast was on 14 January when U-123 put a torpedo into the Norwegian tanker Norness, within sight of Long Island. (There were 13 American destroyers sitting idle in New York harbor.) Those five Uboats would submerge during the day, and attack on the surface at night against targets brightly silhouetted by the coastal lights, many with civilians watching along the coast. The Germans sank 160,000 tons of shipping in two weeks, more than the last six months combined.
U boat crews called the next six months, “Die Glueckliche Zeit” or “The Happy Time”.