Operation Drumbeat

The Second Happy Time, also known among German submarine commanders as the American shooting season, was the informal name for a phase in the Battle of the Atlantic during which Axis submarines attacked merchant shipping and Allied naval vessels along the east coast of North America. The first "Happy Time" was in 1940–41 in the North Atlantic and North Sea.

The Second Happy Time lasted from January 1942 to about August of that year and involved several German naval operations including Operation Paukenschlag (or Operation Drumbeat) and Operation Neuland. German submariners named it the happy time or the golden time as defense measures were weak and disorganized, and the U-boats were able to inflict massive damage with little risk. During this period, Axis submarines sank 609 ships totaling 3.1 million tons and the loss of thousands of lives, mainly those of merchant mariners, against a loss of only 22 U-boats. Although less than losses during the 1917 campaign of the First World War, it was roughly one quarter of all shipping sunk by U-boats during the entire Second World War.

Historian Michael Gannon called it "America's Second Pearl Harbor" and placed the blame for the nation's failure to respond quickly to the attacks on the inaction of Admiral Ernest J. King, commander-in-chief of the U.S. fleet. Others however have pointed out that the belated institution of a convoy system was at least in substantial part due to a severe shortage of suitable escort vessels, without which convoys were seen as actually more vulnerable than lone ships.

Upon Germany's declaration of war on the United States on 11 December 1941 just after the attack on Pearl Harbor, the U.S. was, on paper at least, in a fortunate position. Where the other combatants on the Allied side had already lost thousands of trained sailors and airmen, and were experiencing shortages of ships and aircraft, the U.S. was at full strength (save for its recent losses at Pearl Harbor). The U.S. had the opportunity to learn about modern naval warfare by observing the conflicts in the North Sea and the Mediterranean, and through a close relationship with the United Kingdom. The U.S. Navy had already gained significant experience in countering U-boats in the Atlantic, particularly from April 1941 when President Franklin D. Roosevelt extended the "Pan-American Security Zone" east almost as far as Iceland. The United States had massive manufacturing capacity, including certainly the largest and possibly the most advanced electrical engineering industry in the world. Finally, the U.S. had a favorable geographical position from a defensive point of view: the port of New York, for example, was 3,000 miles to the west of the U-boat bases in Brittany.

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