The Second Happy Time (German: Zweite glückliche Zeit; officially Unternehmen Paukenschlag (transl. Operation Drumbeat), and also known among German submarine commanders as the "American Shooting Season") was 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. Adolf Hitler and Benito Mussolini declared war on the United States on 11 December 1941, and as a result their navies could begin the Second Happy Time.
The Second Happy Time lasted from January 1942 to about August of that year and involved several German naval operations, including 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, against a loss of only 22 U-boats. This led to the loss of thousands of lives, mainly those of merchant mariners. Although fewer than the losses during the 1917 campaign of the First World War, those of this period equaled roughly one quarter of all ships 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 United States Navy (USN). As King also refused British offers to provide the US navy with their own ships, the belated institution of a convoy system was in large 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 US 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 US was at full strength (save for its recent losses at Pearl Harbor). The US 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 USN 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 and a favorable geographical position from a defensive point of view: the port of New York, for example, was 4,800 kilometres (3,000 mi) to the west of the U-boat bases in Brittany.
U-boat commander Vizeadmiral Karl Dönitz saw the entry of the US into the war as a golden opportunity to strike heavy blows in the tonnage war and Hitler ordered an assault on America on 12 December 1941. The standard Type VII submarine had insufficient range to patrol off the coast of North America (although, in due time, Type VII submarines were successfully able to patrol off the eastern seaboard of North America, due to refueling, rearming, and resupply logistical support by Type XIV submarine tender); the only suitable weapons he had on hand were the larger Type IX. These were less maneuverable and slower to submerge, making them much more vulnerable than the Type VIIs. They were also fewer in number.
The American response in early 1942 was hampered by poor organization and doctrine, and a lack of anti-submarine warfare (ASW) aircraft, ships, and personnel.
The USN entered the war without the equivalent of the British Black Swan-class sloop or the River-class frigate despite previous involvement in the Atlantic (see USS Reuben James.) The massive new naval construction program prioritized other types of ships. Fleet destroyers did not have the qualities for ASW; the ideal ASW escort had relatively low speed; carried a large number of depth charges; was highly maneuverable; and had long endurance. The 50 World War I-era destroyers transferred to Britain in the 1941 Destroyers for Bases Agreement would have been poor ASW escorts, even had they been retained, due to poor maneuverability.
The USN had some destroyers available on the east coast at the time of the first attacks. It had previously recalled at least 25 Atlantic Convoy Escort Command Destroyers, including seven at anchor in New York Harbor. It initially refused to use them as escorts even as losses mounted. When the first destroyers were finally released, their employment was hampered by poor doctrine. They were assigned to offensive patrols rather than escorting convoys due to public and political pressure. As late as March, USN escort doctrine was aggressive with an emphasis on destroying attackers, rather than stopping losses. The option of pressing small civilian ships into service as rudimentary convoy escorts in early 1942 was not exercised.
Even if escorts had been available, the USN was unprepared to perform "Naval Control of Shipping" (NCS), the control and tracking of shipping (in convoy or sailing independently), although it had already received the reference material from Canada. Without escorts, the US could not take advantage of the existing Allied NCS. For shipping in the western Atlantic north of the equator, NCS was handled by the Royal Canadian Navy (RCN) since the start of the war; the RCN only passed the responsibility to the USN in July 1942.
Operationally, the USN's ASW effort was fragmented. In theory, Admiral King was responsible for coordinating all ASW activities, including the development of doctrine. In practice, King's many other responsibilities prevented him from doing an adequate job. Therefore, the three Atlantic operational commands – the Atlantic Fleet, the Eastern Sea Frontier, and the Gulf Sea Frontier – were left to develop their own ASW tactics individually. The issue was not resolved until May 1943 with the formation of the United States Tenth Fleet.
British experience in the first two years of World War II, which included the massive losses incurred to their shipping during the First Happy Time confirmed that ships sailing in convoy – with or without escort – were far safer than ships sailing alone. The British recommended that merchant ships should avoid obvious standard routings wherever possible; navigational markers, lighthouses, and other aids to the enemy should be removed, and a strict coastal blackout be enforced. In addition, any available air and sea forces should perform daylight patrols to restrict the U-boats' flexibility. For several months, none of the recommendations were followed. Coastal shipping continued to sail along marked routes and burn normal navigation lights. Boardwalk communities ashore were only 'requested' to 'consider' turning their illuminations off on 18 December 1941, but not in the cities; they did not want to offend the tourism, recreation and business sectors.
The primary target area was the Eastern Sea Frontier, commanded by Rear-Admiral Adolphus Andrews and covering the area from Maine to North Carolina. Andrews had practically no modern forces to work with: on the water he commanded seven Coast Guard cutters, four converted yachts, three 1919-vintage patrol boats, two gunboats dating back to 1905, and four wooden submarine chasers. About 100 aircraft were available, but these were short-range models only suitable for training. As a consequence of the traditionally antagonistic relationship between the USN and the United States Army Air Forces (USAAF), all larger aircraft remained under USAAF control, and in any case the USAAF was neither trained nor equipped for ASW.
Immediately after war was declared on the United States, Dönitz began to implement Operation Paukenschlag (often translated as "drumbeat" or "drumroll", and literally as "timpani beat"). Only six of the twenty operational Type IX boats were available, and one of those six encountered mechanical trouble. This left just five long-range submarines for the opening moves of the campaign.