Second Happy Time The Second Happy Time ( codenamed Operation " Paukenschlag " or Operation Drumbeat ) , also known among German submarine commanders as the American shooting season was the informal name for a phase in the Second Battle of the Atlantic during which Axis submarine s attacked merchant shipping along the east coast of North America . The first " Happy time " was in 1940 – 41 . The Second Happy Time lasted from January 1942 to about August of that year . 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 the second happy time , Axis submarines sank 609 ships totaling 3 . 1 million tons for the loss of only 22 U - boats . This was roughly one quarter of all shipping sunk by U - boats during the entire Second World War . Background . When war broke out between Germany and the United States on 11 December 1941 , the U . S . was in a fortunate position . Where the other combatants had already lost thousands of trained sailors and airmen , and were experiencing shortages of ships and aircraft , the U . S . was at full strength . 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 countering U - boats in the Atlantic , particularly from April 1941 when President 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 . U - boat commander " Vizeadmiral " Karl Dönitz saw the entry of the U . S . into the war as a golden opportunity to strike heavy blows in the tonnage war . The standard Type VII U - boat had insufficient range to patrol off the coast of North America , the only suitable weapons he had on hand were the larger Type IX boats . These were less maneuverable and slower to submerge , making them much more vulnerable than the Type VIIs . They were also fewer in number . Opening moves . Immediately after war was declared on the United States , Dönitz began to implement Operation " Paukenschlag " ( often translated as " drumbeat " or " drumroll " , but it literally means " 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 . Loaded with the maximum possible amounts of fuel , food and ammunition , the first of the five Type IXs left Lorient in France on 18 December 1941 , the others following over the next few days . Each carried sealed orders to be opened after passing 20°W , and directing them to different parts of the North American coast . No charts or sailing directions were available : " Kapitänleutnant " Reinhard Hardegen of , for example , was provided with two tourist guides to New York , one of which contained a fold - out map of the harbor . Each U - boat made routine signals on exiting the Bay of Biscay , which were picked up by the British Y service and plotted in Rodger Winn ' s London Submarine Tracking Room , they were then able to follow the progress of the Type IXs across the Atlantic , and cable an early warning to the Royal Canadian Navy . Working on the slimmest of evidence , Winn correctly deduced the target area and passed a detailed warning to Admiral Ernest J . King , the commander - in - chief of the U . S . fleet , in the United States of a " heavy concentration of U - boats off the North American seaboard " , including the five boats already on station and further groups that were in transit , 21 U - boats in all . Rear - Admiral Frank Leighton of the U . S . Combined Operations and Intelligence Center then informed the responsible area commanders , but little or nothing else was done . The primary target area was the " North Atlantic Coastal 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 boat s , two gunboat s dating back to 1905 , and four wooden submarine chaser s . 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 U . S . Navy and the Army Air Forces , all larger aircraft remained under USAAF control , and in any case the USAAF was neither trained nor equipped for anti - submarine work . American response . 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 . British recommendations were 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 enforced . In addition , any available air and sea forces should perform daylight patrols to restrict the U - boats ' flexibility . None of this was attempted by the Americans . 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 . On 12 January 1942 Admiral Andrews was warned that three or four U - boats were about to commence operations against coastal shipping , but he refused to institute a convoy system on the grounds that this would only provide the U - boats with more targets . Despite the urgent need for action , little was done to try to combat the U - boats . The USN was desperately short of specialized anti - submarine vessels . President Roosevelt ' s 1941 decision to " loan " fifty obsolete World War I - era destroyer s to Britain in exchange for foreign bases , was largely irrelevant . These destroyers had a large turning circle that made them ineffective for anti - submarine work , however their firepower would have been a significant defense against surface attack , which was the major threat in the early part of World War II . The massive new naval construction program had prioritized other types of ships . While freighters and tankers were being sunk in coastal waters , the destroyers that were available remained inactive in port . At least 25 Atlantic Convoy Escort Command Destroyers had been recalled to the U . S . East Coast at the time of the first attacks , including seven at anchor in New York Harbor . When sank the 9 , 500 ton Norwegian tanker " Norness " within sight of Long Island in the early hours of 14 January , no warships were dispatched to investigate , allowing the " U - 123 " to sink the 6 , 700 ton British tanker " Coimbra " off Sandy Hook on the following night before proceeding south towards New Jersey . By this time there were 13 destroyers idle in New York Harbor , yet none were employed to deal with the immediate threat , and over the following nights " U - 123 " was presented with a succession of easy targets , most of them burning navigation lamps . At times , " U - 123 " was operating in coastal waters that were so shallow that they barely allowed it to conceal itself , let alone evade a depth charge attack . 1st wave of U - boats . For the five Type IX boats in the first wave of Operation Drumbeat , it was a bonanza . They cruised along the coast , safely submerged through the day , and surfacing at night to pick off merchant vessels outlined against the lights of the cities . When the first wave of U - boats returned to port in early February , Dönitz wrote that each commander " had such an abundance of opportunities for attack that he could not by any means utilise them all : there were times when there were up to ten ships in sight , sailing with all lights burning on peacetime courses . " A significant failure in U . S . pre - war planning was the lack of any ships suitable for convoy escort work . Escort vessels travel at relatively slow speeds , carry a large number of depth - charges , must be highly manoeuvrable and must stay on station for long periods . Fleet destroyers were equipped for high speed and offensive action and were not the ideal design for this type of work . There was no equivalent of the British " Black Swan " class sloops or the in the U . S . inventory when the war started . This blunder , highly surprising , given that the USN had been involved in anti - submarine work in the Atlantic ( see ) was marginally aggravated by the loss of the obsolete destroyers " loaned " to Britain through Lend - Lease , although these were not considered suitable , as they are vulnerable to counter - attack and lacked the maneuverability to combat submarines . There was also a lack of aircraft suitable for anti - submarine patrol and aircrew trained to use them . Offers of civilian ships and aircraft to act as the Navy ' s " eyes " were repeatedly turned down , only to be accepted later when the situation was clearly critical and the admiral ' s claims to the contrary had become discredited . 2nd and 3rd waves of U - boats . Meanwhile , the second wave of Type IX U - boats had arrived in American waters , and the third wave ( Operation Neuland ) had reached its patrol area off the oil ports of the Caribbean . With such easy pickings available and all Type IX U - boats already committed , Dönitz began sending shorter - range Type VII U - boat s to the U . S . East Coast as well . This required extraordinary measures : cramming every conceivable space with provisions , filling the fresh water tanks with diesel oil , and crossing the Atlantic at very low speed on a single engine to conserve fuel . In the United States there was still no concerted response to the attacks . Overall responsibility rested with Admiral King , but he was preoccupied with the Japanese onslaught in the Pacific . Admiral Andrews ' North Atlantic Coastal Frontier was expanded to take in South Carolina and renamed the Eastern Sea Frontier , but most of the ships and aircraft needed remained under the command of Admiral Royal E . Ingersoll , Commander - in - Chief , Atlantic Fleet , who was often at sea and unavailable to make decisions . Rodger Wynn ' s detailed weekly U - boat situation reports from the Submarine Tracking Room in London were available but ignored . US Propaganda . Popular alarm at the sinkings was dealt - with by a combination of secrecy and misleading propaganda . The US Navy confidently announced that many of the U - boats would " never enjoy the return portion of their voyage " but that unfortunately , details of the sunken U - boats could not be made public lest the information aid the enemy . All citizens who had witnessed the sinking of a U - boat were asked to help keep the secrets safe . The first sinking of a U - boat by a U . S . Navy ship off the coast of the United States did not occur until 14 April 1942 , when the destroyer sank the . It has come to light in recent years that the famous " Loose Lips Sink Ships " propaganda campaign in the U . S . that started in 1942 , was not so much designed to deny German agents knowledge of vessels ' sailing times , but rather to keep American civilian morale up by reducing communication about how much shipping was being sunk during Operation " Drumbeat " . Allied counter - measures get under way . The decision to implement convoys and blackout coastal towns to make ships more difficult to see came slowly . The situation began to change in April when Andrews implemented a limited convoy system in which ships traveled only during daylight hours . Full convoys were in operation by mid - May , resulting in an immediate reduction of Allied shipping losses off the East Coast as Dönitz withdrew the U - boats to seek easier pickings elsewhere . The convoy system was later extended to the Gulf of Mexico with similar dramatic effects , thus proving that King and Andrews ' initial rejection of the convoy system was wrong . In March , 24 Royal Navy anti - submarine trawlers and 10 corvette s were transferred from the UK for the defense of the U . S . East Coast . That same month the Royal Canadian Navy began escorting convoys between Boston and Halifax . The British also transferred 53 Squadron , RAF Coastal Command to Quonset Point , Rhode Island to shield New York Harbor during July 1942 . This squadron moved to Trinidad in August , with a U . S . squadron , to protect the critical sea - lanes from the Venezuelan oil fields back to Norfolk , Virginia until the end of 1942 . Royal Navy and Royal Canadian Navy ships took over escort duties in the Caribbean and on the Aruba – New York tanker run . Fast CU convoys were organized to maintain petroleum fuel stockpiles in the British Isles . The " Kriegsmarine " , while enormously effective during this period , did not go without losses . Sinkings of German U - boats at the hands of United States forces during this time included :