Second Happy Time
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. Adolf Hitler and Benito Mussolini declared war on the United States on 11 December 1941 so 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 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,:p292 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.
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 and Hitler ordered an assault on America on 12 December 1941. 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.
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.
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 U-123, for example, was provided with two tourist guides to New York, one of which contained a fold-out map of the harbor.:p137
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, which 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, 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 Edwin T. Layton of the U.S. Combined Operations and Intelligence Center then informed the responsible area commanders, but little or nothing else was done.:Chapter 9
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 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.:p182
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. :p186 On 12 January 1942, Admiral Andrews was warned that "three or four U-boats" were about to commence operations against coastal shipping (in fact there were three),:p212 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 destroyers 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 US East Coast at the time of the first attacks, including seven at anchor in New York Harbor.:p238
When U-123 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.
For the five Type IX boats in the first wave of attack, known as 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.
- Reinhard Hardegen in U-123 sank seven ships totalling 46,744 tons before he ran out of torpedoes and returned to base;
- Ernst Kals in U-130 sank six ships of 36,988 tons;
- Robert-Richard Zapp in U-66 sank five ships of 33,456 tons;
- Heinrich Bleichrodt in U-109 sank four ships of 27,651 tons; and
- Ulrich Folkers on his first patrol in U-125 sank one 6,666 ton vessel, the West Ivis (he was criticized by Dönitz for his poor performance, although he would later win the Knight's Cross of the Iron Cross.):p271
When the first wave of U-boats returned to port through the early part of February, Dönitz wrote that each commander "had such an abundance of opportunities for 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."
A significant flaw in U.S. pre-war planning was the failure to provide ships suitable for convoy-escort work. Escort vessels travel at relatively slow speeds; carry a large number of depth charges; must be highly maneuverable; and must stay on station for long periods. The fleet destroyers equipped for high speed and offensive action that were available were not the ideal design for this type of escort work. When the war started, the U.S. had no equivalent of the more effective British Black Swan-class sloops or the River-class frigate in their inventory. This blunder was highly surprising since the American Navy (USN) had previously been involved in anti-submarine work in the Atlantic (see USS Reuben James) and at the time was marginally aggravated by the loss of the destroyers "loaned" to Britain through Lend-Lease; however, these vessels would have been largely obsolete for anti-submarine purposes due to their counter-attack vulnerability and inherent inability to maneuver as required to combat submarines. The U.S. also lacked both aircraft suitable for anti-submarine patrol and any aircrew trained to use them at that time.
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[who?] to the contrary had become discredited.
Meanwhile, the second wave of Type IX U-boats had arrived in North 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-boats to the U.S. East Coast as well. This required extraordinary measures: cramming every conceivable space with provisions, some even 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.
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.
Chronology of attacks
- 14 January – Panamanian tanker Norness sunk by U-123 at 
- 18 January – U.S. tanker Allan Jackson sunk by U-66 at (23 of 35 crewmen perished)
- 18 January – U.S. tanker Malay damaged by U-123 at  (5 crewmen perished)
- 19 January – U.S. steamship City of Atlanta sunk by U-123 at (43 of 46 crewmen perished)
- 19 January – Canadian steamship Lady Hawkins sunk by U-66 at 
- 22 January – U.S. freighter Norvana sunk by U-123 south of Cape Hatteras (no survivors)
- 23 January – U.S. collier Venore sunk by U-66 at  (17 of 41 crewmen perished)
- 25 January – U.S. tanker Olney damaged by U-125 at 
- 26 January – U.S. freighter West Ivis sunk by U-125 (all 45 crewmen perished)
- 27 January – U.S. tanker Francis E. Powell sunk by U-130 at  (4 of 32 crewmen perished)
- 27 January – U.S. tanker Halo damaged by U-130 at 
- 30 January – U.S. tanker Rochester sunk by U-106 at (3 of 32 crewmen perished)
- 31 January – U.S. San Arcadio sunk by U-107 at 
- 31 January – U.S. Tacoma Star sunk by U-109 at 
- 2 February – U.S. tanker W.L. Steed sunk by U-103 at (34 of 38 crewmen perished)
- 3 February – Panamanian freighter San Gil sunk by U-103 at  (2 of 40 crewmen perished)
- 4 February – U.S. tanker India Arrow sunk by U-103 at  (26 of 38 crewmen perished)
- 5 February – U.S.s tanker China Arrow sunk by U-103 at 
- 6 February – U.S. freighter Major Wheeler sunk by U-107 (all 35 crewmen perished)
- 8 February – British freighter Ocean Venture sunk by U-108 at 
- 10 February – Canadian tanker Victolite sunk by U-564 at 
- 15 February – Brazilian steamship Buarque sunk by U-432 at 
- 18 February – Brazilian tanker Olinda sunk by U-432 at 
- 19 February – U.S. tanker Pan Massachusetts sunk by U-128 at (20 of 38 crewmen perished)
- 20 February – U.S. freighter Azalea City sunk by U-432 at  (All 38 crewmen perished)
- 21 February – U.S. tanker Republic sunk by U-504 at (5 of 29 crewmen perished)
- 22 February – U.S. tanker Cities Service Empire sunk by U-128 at  (14 of 50 crewmen perished)
- 22 February – U.S. tanker W.D. Anderson sunk by U-504 at  (35 of 36 crewmen perished)
- 26 February – U.S. bulk carrier Marore sunk by U-432 at 
- 26 February – U.S. tanker R.P. Resor sunk by U-578 at  (47 of 49 crewmen perished)
- 28 February – U.S. destroyer Jacob Jones sunk by U-578 at 
- 7 March – U.S. freighter Barbara sunk by U-126 at 
- 7 March – U.S. freighter Cardonia sunk by U-126 at 
- 7 March – Brazilian steamship Arbabutan sunk by U-155 at 
- 9 March – Brazilian steamship Cayru sunk by U-94 at 
- 10 March – U.S. tanker Gulftrade sunk by U-588 at 
- 11 March – U.S. freighter Texan sunk by U-126 at 
- 11 March – U.S. freighter Caribsea sunk by U-158 at 
- 12 March – U.S. tanker John D. Gill sunk by U-158 at  (4 crewmen perished)
- 12 March – U.S. freighter Olga sunk by U-126 at 
- 12 March – U.S. freighter Colabee damaged by U-126 at 
- 13 March – U.S. schooner Albert F. Paul sunk by U-332 at  (no survivors)
- 13 March – Chilean freighter Tolten sunk by U-404 at (15 of 16 crewmen perished)
- 14 March – U.S. collier Lemuel Burrows sunk by U-404 at 
- 15 March – U.S. tanker Ario sunk by U-158 at  (7 of 36 crewmen perished)
- 15 March – U.S. tanker Olean sunk by U-158 at 
- 16 March – U.S. tanker Australia sunk by U-332 at 
- 16 March – British tanker San Demetrio sunk by U-404 at 
- 17 March – U.S. tanker Acme damaged by U-124 at 
- 17 March – Greek freighter Kassandra Louloudi sunk by U-124 four mile off Diamond Shoals gas buoy
- 17 March – Honduran freighter Ceiba sunk by U-124 at 
- 18 March – U.S. tanker E.M. Clark sunk by U-124 at 
- 18 March – U.S. tanker Papoose sunk by U-124 at 
- 18 March – U.S. tanker W.E. Hutton sunk by U-332 at  (13 of 36 crewmen perished)
- 19 March – U.S. freighter Liberator sunk by U-332 at  (5 crewmen perished)
- 20 March – U.S. tanker Oakmar sunk by U-71 at  (6 of 36 crewmen perished)
- 21 March – U.S. tanker Esso Nashville sunk by U-124 at 
- 21 March – U.S. tanker Atlantic Sun damaged by U-124
- 22 March – U.S. tanker Naeco sunk by U-124 at  (24 of 39 crewmen perished)
- 25 March – Dutch tanker Ocana sunk by U-552 at 
- 26 March – U.S. Q-ship USS Atik sunk by U-123 at (All 139 crewmen perished)
- 26 March – U.S. tanker Dixie Arrow sunk by U-71 at  (11 of 33 crewmen perished)
- 26 March – Panamanian tanker Equipoise sunk by U-160 at 
- 29 March – U.S. steamship City of New York sunk by U-160 at  (24 of 157 crewmen perished)
- 31 March – U.S. tug Menominee and barges Allegheny and Barnegat sunk by U-754 at 
- 31 March – U.S. tanker Tiger sunk by U-754 (1 of 43 crewmen perishes)
- 3 April – U.S. freighter Otho sunk by U-754 at  (31 of 53 crewmen perished)
- 4 April – U.S. tanker Byron D. Benson sunk by U-552 at  (9 of 37 crewmen perished)
- 6 April – U.S. tanker Bidwell damaged by U-160  (1 of 33 crewmen perishes)
- 7 April – Norwegian freighter Lancing sunk by U-552 off Cape Hatteras
- 7 April – British tanker British Splendour sunk by U-552 off Cape Hatteras
- 8 April – U.S. tanker Oklahoma damaged by U-123 at  (19 of 37 crewmen perished)
- 8 April – U.S. tanker Esso Baton Rouge damaged by U-123 at  (3 of 39 crewmen perished)
- 9 April – U.S. freighter Esparta sunk by U-123  (1 of 40 crewmen perishes)
- 9 April – U.S. freighter Malchace sunk by U-160 at  (1 of 29 crewmen perished)
- 9 April – U.S. tanker Atlas sunk by U-552 at  (2 of 34 crewmen perished)
- 9 April – tanker Tamaulipas sunk by U-552 at  (2 of 37 crewmen perished)
- 10 April – U.S. tanker Gulfamerica sunk by U-123 at  (19 of 48 crewmen perished)
- 11 April – U.S. tanker Harry F. Sinclair Jr. damaged by U-203 at  (10 of 36 crewmen perished)
- 11 April – British steamship Ulysses sunk by U-160 at 
- 12 April – Panamanian tanker Stanvac Melbourne sunk by U-203 at 
- 12 April – U.S. freighter Leslie sunk by U-123 at  (3 of 32 crewmen perished)
- 14 April – British freighter Empire Thrush sunk by U-203 at 
- 14 April – U.S. freighter Margaret sunk by U-571 at (All 29 crewmen perished)
- 15 April – U.S. freighter Robin Hood sunk by U-575 at  (14 of 38 crewmen perished)
- 16 April – U.S. freighter Alcoa Guide sunk by U-123 at  (6 of 34 crewmen perished)
- 17 April – Argentine tanker Victoria damaged by U-201 at 
- 18 April – U.S. tanker Axtell J. Byles damaged by U-136 at 
- 19 April – U.S. freighter Steel Maker sunk by U-136 at  (1 of 45 crewmen perished)
- 20 April – U.S. freighter West Imboden sunk by U-752 at 
- 21 April – U.S. freighter Pipestone County sunk by U-576 at 
- 21 April – U.S. freighter San Jacinto sunk by U-201 at  (14 of 183 crewmen perished)
- 29 April – U.S. tanker Mobiloil sunk by U-108 at 
- 29 April – U.S. tanker Federal sunk by U-507 at (5 of 33 crewmen perished)
- 2 May – U.S. armed yacht Cythera sunk by U-402 off North Carolina (66 of 68 crewmen perished)
- 4 May – U.S. tanker Norlindo sunk by U-507 at  (5 of 28 crewmen perished)
- 4 May – U.S. tanker Munger T. Ball sunk by U-507 at (30 of 34 crewmen perished)
- 4 May – U.S. tanker Joseph M. Cudahy sunk by U-507 at  (27 of 37 crewmen perished)
- 4 May – U.S. freighter Delisle damaged by U-564 at (2 of 36 crewmen perished)
- 5 May – U.S. freighter Afoundria sunk by U-108 at 
- 5 May – U.S. tanker Java Arrow damaged by U-333 at (2 of 47 crewmen perished)
- 6 May – U.S. tanker Halsey sunk by U-333 at  (5 of 28 crewmen perished)
- 6 May – U.S. freighter Alcoa Puritan sunk by U-507 at 
- 8 May – U.S. freighter Ohioan sunk by U-564 at  (15 of 37 crewmen perished)
- 10 May – U.S. tanker Aurora damaged by U-506 at  (1 of 50 crewmen perished)
- 12 May – U.S. tanker Virginia sunk by U-507 at  (27 of 41 crewmen perished)
- 13 May – U.S. tanker Gulfprince damaged by U-507 at 
- 13 May – U.S. tanker Gulfpenn sunk by U-506 at  (13 of 38 crewmen perished)
- 13 May – U.S. freighter David McKelvy sunk by U-506 at  (17 of 36 crewmen perished)
- 15 May – U.S. freighter Nicarao sunk by U-751 at  (8 of 39 crewmen perished)
- 16 May – U.S. tanker Sun damaged by U-506 at 
- 16 May – U.S. tanker William C. McTarnahan damaged by U-506 at  (18 of 38 crewmen perished)
- 16 May – U.S. tanker Gulfoil sunk by U-506 at  (21 of 40 crewmen perished)
- 19 May – U.S. freighter Heredia sunk by U-506 at  (36 of 62 crewmen perished)
- 19 May – U.S. freighter Ogontz sunk by U-103 at  (19 of 41 crewmen perished)
- 20 May – U.S. tanker Halo sunk by U-506 at  (21 of 42 crewmen perished)
- 20 May – U.S. freighter George Calvert sunk by U-752 at  (3 of 61 crewmen perished)
- 21 May – U.S. freighter Plow City sunk by U-588 at  (1 of 30 crewmen perished)
- 26 May – U.S. tanker Carrabulle sunk by U-106 at  (22 of 40 crewmen perished)
- 26 May – U.S. freighter Atenas damaged by U-106 at 
- 30 May – U.S. freighter Alcoa Shipper sunk by U-404 at (7 of 32 crewmen perished)
- 1 June – U.S. freighter West Notus sunk by U-404 at  (4 of 40 crewmen perished)
- 1 June – U.S. freighter Hampton Roads sunk by U-106 at  (5 of 28 crewmen perished)
- 3 June – U.S. freighter M.F. Elliott sunk by U-502 off the Florida Keys (13 of 45 crewmen perished)
- 10 June – U.S. tanker Hagan sunk by U-157 at  (6 of 44 crewmen perished)
- 12 June – U.S. tanker Cities Service Toledo sunk by U-158 at  (15 of 45 crewmen perished)
The decision to implement convoys and blackout coastal towns to make ships more difficult to see came slowly. The situation began to change on 1 April when Andrews restricted ships to traveling only during daylight hours between protected anchorages. On 14 May 1942 the first coastal convoy sailed from Hampton Roads for Key West; and convoys later extended northward to Boston, where they connected with the BX convoys to Halifax initiated by the Royal Canadian Navy in March. Full convoys produced 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 corvettes were transferred from the UK for the defense of the U.S. East Coast. 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 Allied forces during this time included:
- U-85: sunk on 14 April by the destroyer USS Roper in position off Cape Hatteras, the first sinking in U.S. waters
- U-352: sunk on 9 May by the cutter USCGC Icarus in position off Cape Hatteras
- U-157: sunk on 13 June by the cutter USCGC Thetis in position off Havana, Cuba
- U-158: sunk on 30 June by a Mariner aircraft (USN VP-74) in position west of Bermuda
- U-215: sunk on 3 July by the Armed ASW Trawler HMS Le Tiger in position by depth charges
- U-701: sunk on 7 July by a Lockheed Hudson aircraft in position off Cape Hatteras
- U-153: sunk on 13 July by the destroyer USS Lansdowne in position off Colón, Panama
- U-576: sunk on 15 July by two Vought OS2U Kingfisher aircraft and ramming by the U.S. motor vessel Unicoi in position off Cape Hatteras
- U-166: sunk on 30 July by the US Navy patrol craft, PC 566, in position in the Gulf of Mexico, the only U-boat sunk in the Gulf of Mexico during World War II
- U-165 sunk on 27 September 1942 by a Vickers Wellington of 311/Q Squadron, RAF (with a Czech aircrew)
- U-132 sunk on 5 November 1942 by aircraft of No. 120 Squadron RAF.
- U-517 sunk 17 November 1942 by Fairey Albacores of 817 Naval Air Squadron from the aircraft carrier HMS Victorious.
- U-553 lost at sea 28 January 1943
- U-69 active in the east coast operations, rammed and sunk on 17 February 1943 by HMS Fame
- U-106 active in the east coast operations, sunk 2 August 1943, by aircraft attack by No. 461 Squadron RAAF flown by Flight Lieutenant A. F. Clarke.
- Miller, Nathan: War at Sea: A Naval History of World War II. Oxford University Press, 1997, p. 295. ISBN 0-19-511038-2
- Duncan Redford; Philip D. Grove (2014). The Royal Navy: A History Since 1900. I.B. Tauris. p. 182
- Michael Gannon, Operation Drumbeat: the dramatic true story of Germany's first U-boat attacks along the American coast in World War II, 1990, Harper and Row publishers, ISBN 0-06-016155-8
- Churchill, Winston (1950). The Hinge of Fate. Boston: Houghton Mifflin Company. p. 111.
- Timothy J. Ryan and Jan M. Copes To Die Gallantly – The Battle of the Atlantic, 1994 Westview Press, Chapter 7.
- Blair p.438
- Fairbank White, David – Bitter Ocean – The dramatic story of the Battle of the Atlantic 1939–1945, 2006, Headline Publishing Group ISBN 978-0-7553-1089-0, p. 146
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- Fairbank White, p. 147
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- Churchill, Winston (1950). The Hinge of Fate. Boston: Houghton Mifflin Company. pp. 122&123.
- Fairbank White, p. 149
- "The Battle of the Atlantic". iwm.org.uk.
- Cressman (2000) p.106
- Cressman (2000) p.108
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- Cressman (2000) p.110
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- Boyle, Alan (6 May 2015). "How an Expedition to Study a Sunken Nazi U-Boat Rescued a Reputation". NBC News. Retrieved 7 May 2015.
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- Behrens, C. B. A. Merchant Shipping and the Demands of War. London: H.M. Stationery Office, 1955.
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- Blair, Clay Hitler's U-Boat War: The Hunters 1939–1942 Random House (1996) ISBN 0394588398
- Morison, Samuel Eliot. A History of U.S. Naval Operations in World War II Vol. I: The Battle of the Atlantic, September 1939 – May 1943. Boston: Little, Brown, 1947.
- Churchill, Winston. The Second World War Vol. IV: The Grand Alliance. Boston: Houghton Mifflin, 1950.
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- Fairbank White, David. Bitter Ocean: The dramatic story of the Battle of the Atlantic 1939–1945, 2006, Headline Publishing Group, ISBN 9780755310890.
- Gannon, Michael. Operation Drumbeat: The Dramatic True Story of Germany's First U-Boat Attacks Along the American Coast in World War II. New York: Harper & Row, 1990. ISBN 0060161558.
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- No 53 Squadron, Royal Air Force, list of bases
- More information about RN Armed Trawlers and the Royal Naval Patrol Service in WW2