In mid-1940, German submariners enjoyed a period nicknamed the Happy Time (Die Glückliche Zeit) during which they were able to sink 282 Allied ships in the Atlantic Ocean totaling 1,489,795 tons. As the British improved convoy techniques, the Happy Time in late 1940, but German submarines continued to pose a serious threat for Allied shipping in the Atlantic.
Long before the United States entered the war it had been violating its neutrality by sending supplies and surplus warships to the United Kingdom. American politicians claimed that transports of any nation docking at American ports could do trade without restriction, but they also knew that only British and French vessels made visits to the United States. With this policy in place, however, it was inevitable that attacks on American “neutral” shipping occurred. On 31 Oct 1941, while escorting a British convoy, the American destroyer USS Reuben James was torpedoed and sunk by German submarine U-562; 115 of the 160 aboard were killed as the result of the first American naval vessel sunk by the Germans before the war started for the United States. Isolationist sentiments still ran strong in the US, however, and President Roosevelt could not rally enough support based on this event to declare an alliance with Britain; all he could do was, as he had already ordered months prior, to continue US Navy patrols across the Atlantic Ocean, going as far as Iceland.
The position of the United States changed when it declared war on Germany on 11 Dec 1941, three days after the declaration of war on Japan. German Admiral Karl Dönitz immediately planned for his long-range submarines to strike the American coastal waters. Codenamed Operation Paukenschlag (Drumbeat or Timpani Beat), five Type IX submarines departed Lorient, France on 18 Dec 1941. The British Y service picked up signals from these submarines; Rodger Winn of the London Submarine Tracking Room suspected that these submarines might be heading to the Western Atlantic, and warned the Canadians and the Americans of a “heavy concentration of U-boats off the North American seaboard”. Rear Admiral Frank Leighton of the US Combined Operations and Intelligence Center received the message and passed it on to, among others, Rear Admiral Adolphus Andrews who was in charge of coastal defense along the Maine to North Carolina coast, but he could do little against attacks by modern German submarines as his fleet only consisted of 7 US Coast Guard cutters, four yachts, and several WW1-vintage vessels. While Andrews’ inaction was due to lack of resources under his command, the fact that little other actions were taken could only be blamed on personal failure; American coastal shipping continued to continue with lights on, and lighthouses continued to operate and provide navigational aid to the enemy. On 12 Jan 1942, Andrews received another warning, but he refused to group coastal shipping into convoys (a sentiment shared by US Navy Admiral Ernest King). Two days later, on 14 Jan, German submarine U-123 struck within sight of Long Island, New York, United States, sinking Norwegian tanker Norness; the Andrews did not dispatch any of his 13 destroyers in New York harbor to investigate. On the night of 15 Jan, seeing no ships came to pursue, U-123 sank British tanker Coimbra off Sandy Hook, New Jersey, United States. U-123’s crew was pleasantly surprised to still see no actions taken against these attacks, and continued to operate off New Jersey with impunity, sinking five more ships before heading back to France. U-123’s sister ships U-130, U-66, U-109, and U-125 collectively sank 16 ships, making the grand total 23. When all five of the Type IX submarines returned to France, Dönitz actually criticized U-125’s commanding officer Ulrich Folkers for his lack of aggressiveness, having destroyed only one Allied ship. Dönitz later wrote that on this first expedition to the American coast each commander “had such an abundance of opportunities for an attack that he could not by any means utilize them all: there were times when there were up to ten ships in sight, sailing with all lights burning on peacetime courses.”
The success led to second and third waves of German submarines being sent to the American coast; around this time, the nickname Second Happy Time began to surface, with the initial 1940 success as the First Happy Time. In addition to the long-range Type IX submarines, shorter range submarines were being dispatched to North America as well, with all available space used for extra food, water, and fuel to extend the submarines’ range.
In Mar 1942, 24 British Royal Navy anti-submarine trawlers and 10 Corvettes were deployed on the east coast of the United States to help alleviate the situation. In the same month, Royal Canadian Navy expanded its area of operations so that it could escort convoys sailing between Boston, Massachusetts, the United States and Halifax, Nova Scotia, Canada.
The first successful sinking of a German submarine would not occur until 14 Apr 1942 when the destroyer USS Roper sank U-85. In the same month, Andrews finally agreed to implement a limited convoy system and only allowing ships to travel in daylight. By mid-May 1942, full convoys were finally in operation and the number of Allied ships sunk off the American coast immediately decreased. Dönitz quickly noticed the change in American tactics and scaled-down submarine operations off the American coast. Starting in Jul 1942, the British RAF Coastal Command transferred No. 53 Squadron to various bases in North America to bolster anti-submarine defenses. Noting that the Americans and the Allies finally began to tighten defenses on the US coast, Dönitz called off this campaign. During the Second Happy Time which lasted more than seven months, the Germans sank 609 ships totaling 3,100,000 tons at the cost of only 22 submarines. This number would represent about 25% of all Allied shipping sunk by German submarines during this period.