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 submarines 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 GERMAN SUBMARINE U-123, 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 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.

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 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 U.S. East Coast at the time of the first attacks, including seven at anchor in New York Harbor.

When GERMAN SUBMARINE 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.

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.
 * Reinhard Hardegen in GERMAN SUBMARINE U-123 sank seven ships totalling 46,744 tons before he ran out of torpedoes and returned to base;
 * Ernst Kals in GERMAN SUBMARINE U-130 sank six ships of 36,988 tons;
 * Robert-Richard Zapp in GERMAN SUBMARINE U-66 sank five ships of 33,456 tons;
 * Heinrich Bleichrodt in GERMAN SUBMARINE U-109 sank four ships of 27,651 tons; and
 * Ulrich Folkers on his first patrol in GERMAN SUBMARINE U-125 sank only a single 6,666 ton vessel, for which he was criticized by Dönitz (although he would later win the Knight's Cross of the Iron Cross.)



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 River-class frigate 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 USS Reuben James (DD-245)) 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-boats 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 USS Roper (DD-147) sank the GERMAN SUBMARINE U-85. 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.

Chronology of attacks off the U.S. East Coast

 * 14 January – The Panamanian tanker Norness sunk by GERMAN SUBMARINE U-123 at 40.44°N, -70.908°W
 * 18 January – The United States tanker Allan Jackson sunk by GERMAN SUBMARINE U-66 at 35.95°N, -74.33°W (23 of 35 crewmen perished)
 * 18 January – The United States tanker Malay damaged by U-123 at 35.42°N, -75.38°W (5 crewmen perished)
 * 19 January – The United States steamship City of Atlanta sunk by GERMAN SUBMARINE U-123 at 35.7°N, -75.35°W (43 of 46 crewmen perished)
 * 19 January – The Canadian steamship Lady Hawkins sunk by U-66 at 35°N, -72.5°W
 * 22 January – The United States freighter Norvana sunk by U-123 south of Cape Hatteras (no survivors)
 * 23 January – The United States collier Venore sunk by U-66 at 35.83°N, -75.33°W (17 of 41 crewmen perished)
 * 25 January – The United States tanker Olney damaged by GERMAN SUBMARINE U-125 at 37.92°N, -74.93°W
 * 26 January – The United States freighter West Ivis sunk by U-125 (all 45 crewmen perished)
 * 27 January – The United States tanker Francis E. Powell sunk by U-130 at 37.75°N, -74.88°W (4 of 32 crewmen perish)
 * 27 January – The United States tanker Halo damaged by U-130 at 35.55°N, -75.33°W
 * 30 January – The United States tanker Rochester sunk by GERMAN SUBMARINE U-106 at 37.17°N, -73.97°W (3 of 32 crewmen perished)
 * 31 January – The British tanker San Arcadio sunk by GERMAN SUBMARINE U-107 at 38.17°N, -63.83°W
 * 31 January – The British tanker Tacoma Star sunk by U-109 at 37.55°N, -69.35°W
 * 2 February – The United States tanker W.L.Steed sunk by GERMAN SUBMARINE U-103 at 38.42°N, -72.72°W (34 of 38 crewmen perished)
 * 3 February – The Panamanian freighter San Gil sunk by U-103 at 38.08°N, -74.67°W (2 of 40 crewmen perished)
 * 4 February – The United States tanker India Arrow sunk by U-103 at 38.8°N, -73.67°W (26 of 38 crewmen perished)
 * 5 February – The United States tanker China Arrow sunk by U-103 at 38.73°N, -73.3°W
 * 6 February – The United States freighter Major Wheeler sunk by U-107 (all 35 crewmen perish)
 * 8 February – The British freighter Ocean Venture sunk by U-108 at 37.08°N, -74.75°W
 * 10 February – The Canadian tanker Victolite sunk by GERMAN SUBMARINE U-564 at 36.2°N, -67.23°W
 * 15 February – The Brazilian steamship Buarque sunk by U-432 at 36.58°N, -75.33°W
 * 18 February – The Brazilian tanker Olinda sunk by U-432 at 37.5°N, -75°W
 * 19 February – The United States tanker Pan Massachusetts sunk by GERMAN SUBMARINE U-128 at 28.45°N, -80.13°W (20 of 38 crewmen perished)
 * 20 February – The United States freighter Azalea City sunk by U-432 at 38°N, -73°W (All 38 crewmen perished)
 * 21 February – The United States tanker Republic sunk by GERMAN SUBMARINE U-504 at 27.08°N, -80.25°W (5 of 29 crewmen perished)
 * 22 February – The United States tanker Cities Service Empire sunk by U-128 at 28°N, -80.27°W (14 of 50 crewmen perished)
 * 22 February – The United States tanker W.D.Anderson sunk by U-504 at 27.15°N, -79.93°W (35 of 36 crewmen perished)
 * 26 February – The United States bulk carrier Marore sunk by U-432 at 35.55°N, -74.97°W
 * 26 February – The United States tanker R.P.Resor sunk by U-578 at 39.78°N, -73.43°W (47 of 49 crewmen perished)
 * 28 February – The United States destroyer USS Jacob Jones (DD-130) sunk by U-578 at 38.7°N, -74.65°W
 * 7 March – The United States freighter Barbara sunk by U-126 at 20°N, -73.93°W
 * 7 March – The United States freighter Cardonia sunk by U-126 at 19.88°N, -73.45°W
 * 7 March – The Brazilian steamship Arbabutan sunk by GERMAN SUBMARINE U-155 at 35.25°N, -73.92°W
 * 9 March – The Brazilian steamship Cayru sunk by GERMAN SUBMARINE U-94 at 39.16°N, -72.03°W
 * 10 March – The United States tanker Gulftrade sunk by U-588 at 39.84°N, -73.87°W
 * 11 March – The United States freighter Texan sunk by U-126 at 21.53°N, -76.4°W
 * 11 March – The United States freighter Caribsea sunk by U-158 at 34.67°N, -76.16°W
 * 12 March – The United States tanker John D. Gill sunk by U-158 at 35.92°N, -77.65°W (4 crewmen perished)
 * 12 March – The United States freighter Olga sunk by U-126 at 23.65°N, -77°W
 * 12 March – The United States freighter Colabee damaged by U-126 at 22.23°N, -77.58°W
 * 13 March – The United States schooner Albert F. Paul sunk by U-332 at 26°N, -72°W (no survivors)
 * 13 March – The Chilean freighter Tolten sunk by GERMAN SUBMARINE U-404 at 40.16°N, -73.84°W (15 of 16 crewmen perished)
 * 14 March – The United States collier Lemuel Burrows sunk by U-404 at 39.2°N, -74.27°W
 * 15 March – The United States tanker Ario sunk by U-158 at 34.33°N, -76.65°W (7 of 36 crewmen perished)
 * 15 March – The United States tanker Olean sunk by U-158 at 34.4°N, -76.48°W
 * 16 March – The United States tanker Australia sunk by U-332 at 35.12°N, -75.37°W
 * 16 March – The British tanker San Demetrio sunk by U-404 at 37.05°N, -73.84°W
 * 17 March – The United States tanker Acme damaged by GERMAN SUBMARINE U-124 at 35.1°N, -76.67°W
 * 17 March – The Greek freighter Kassandra Louloudi sunk by U-124 four mile off Diamond Shoals gas buoy
 * 17 March – The Honduran freighter Ceiba sunk by U-124 at 35.72°N, -73.82°W
 * 18 March – The United States tanker E.M.Clark sunk by U-124 at 34.84°N, -75.58°W
 * 18 March – The United States tanker Papoose sunk by U-124 at 34.28°N, -76.65°W
 * 18 March – The United States tanker W.E.Hutton sunk by U-332 at 34.08°N, -76.67°W (13 of 36 crewmen perished)
 * 19 March – The United States freighter Liberator sunk by U-332 at 35.08°N, -75.5°W (5 crewmen perished)
 * 20 March – The United States tanker Oakmar sunk by U-71 at 36.35°N, -68.84°W (6 of 36 crewmen perished)
 * 21 March – The United States tanker Esso Nashville sunk by U-124 at 33.58°N, -77.37°W
 * 21 March – The United States tanker Atlantic Sun damaged by U-124
 * 22 March – The United States tanker Naeco sunk by U-124 at 33.98°N, -76.67°W (24 of 39 crewmen perished)
 * 25 March – The Dutch tanker Ocana sunk by GERMAN SUBMARINE U-552 at 42.6°N, -64.42°W
 * 26 March – The United States Q-ship USS Atik (AK-101) sunk by U-123 at 36°N, -70°W (All 139 crewmen perished)
 * 26 March – The United States tanker Dixie Arrow sunk by U-71 at 34.98°N, -75.55°W (11 of 33 crewmen perished)
 * 26 March – The Panamanian tanker Equipoise sunk by U-160 at 36.6°N, -74.75°W
 * 29 March – The United States steamship City of New York sunk by U-160 at 35.27°N, -74.42°W (24 of 157 crewmen perished)
 * 31 March – The United States tug Menominee and barges Allegheny and Barnegat sunk by GERMAN SUBMARINE U-754 at 37.57°N, -75.42°W
 * 31 March – The United States tanker Tiger sunk by U-754 (1 of 43 crewmen perishes)
 * 3 April – The United States freighter Otho sunk by U-754 at 36.42°N, -71.95°W (31 of 53 crewmen perished)
 * 4 April – The United States tanker Byron D. Benson sunk by U-552 at 36.13°N, -75.53°W (9 of 37 crewmen perished)
 * 6 April – The United States tanker Bidwell damaged by U-160 34.42°N, -75.95°W (1 of 33 crewmen perishes)
 * 7 April – The Norwegian freighter Lancing sunk by U-552 off Cape Hatteras
 * 7 April – The British tanker British Splendour sunk by U-552 off Cape Hatteras
 * 8 April – The United States tanker Oklahoma damaged by U-123 at 31.3°N, -80.98°W (19 of 37 crewmen perished)
 * 8 April – The United States tanker Esso Baton Rouge damaged by U-123 at 31.22°N, -80.08°W (3 of 39 crewmen perished)
 * 9 April – The United States freighter Esparta sunk by U-123 30.77°N, -81.18°W (1 of 40 crewmen perishes)
 * 9 April – The United States freighter Malchace sunk by U-160 at 34.47°N, -75.93°W (1 of 29 crewmen perished)
 * 9 April – The United States tanker Atlas sunk by U-552 at 34.45°N, -76.27°W (2 of 34 crewmen perished)
 * 9 April – The tanker Tamaulipas sunk by U-552 at 34.42°N, -76°W (2 of 37 crewmen perished)
 * 10 April – The United States tanker Gulfamerica sunk by U-123 at 30.23°N, -81.3°W (19 of 48 crewmen perished)
 * 11 April – The United States tanker Harry F. Sinclair Jr. damaged by U-203 at 34.42°N, -76.5°W (10 of 36 crewmen perished)
 * 11 April – The British steamship Ulysses sunk by U-160 at 34.38°N, -75.58°W
 * 12 April – The Panamanian tanker Stanvac Melbourne sunk by U-203 at 33.88°N, -77.48°W
 * 12 April – The United States freighter Leslie sunk by U-123 at 28.62°N, -80.42°W (3 of 32 crewmen perished)
 * 14 April – The British freighter Empire Thrush sunk by U-203 at 35.2°N, -75.23°W
 * 14 April – The United States freighter Margaret sunk by GERMAN SUBMARINE U-571 at 35.2°N, -75.23°W (All 29 crewmen perished)
 * 15 April – The United States freighter Robin Hood sunk by U-575 at 38.65°N, -66.63°W (14 of 38 crewmen perished)
 * 16 April – The United States freighter Alcoa Guide sunk by U-123 at 35.57°N, -70.13°W (6 of 34 crewmen perished)
 * 17 April – The Argentine tanker Victoria damaged by GERMAN SUBMARINE U-201 at 36.68°N, -68.8°W
 * 18 April – The United States tanker Axtell J. Byles damaged by U-136 at 35.53°N, -75.32°W
 * 19 April – The United States freighter Steel Maker sunk by U-136 at 33.08°N, -70.6°W (1 of 45 crewmen perished)
 * 20 April – The United States freighter West Imboden sunk by U-752 at 41.23°N, -65.9°W
 * 21 April – The United States freighter Pipestone County sunk by U-576 at 37.58°N, -66.33°W
 * 21 April – The United States freighter San Jacinto sunk by U-201 at 31.16°N, -70.75°W (14 of 183 crewmen perished)
 * 29 April – The United States tanker Mobiloil sunk by U-108 at 26.16°N, -66.25°W
 * 29 April – The United States tanker Federal sunk by GERMAN SUBMARINE U-507 at 21.22°N, -76.08°W (5 of 33 crewmen perished)
 * 2 May – The United States armed yacht USS Cythera (PY-26) sunk by GERMAN SUBMARINE U-402 off North Carolina (66 of 68 crewmen perish)
 * 4 May – The United States tanker Norlindo sunk by U-507 at 24.95°N, -84°W (5 of 28 crewmen perish)
 * 4 May – The United States tanker SS Munger T. Ball sunk by U-507 at 25.28°N, -83.95°W (30 of 34 crewmen perished)
 * 4 May – The United States tanker Joseph M. Cudahy sunk by U-507 at 25.95°N, -83.95°W (27 of 37 crewmen perished)
 * 4 May – The United States freighter Delisle damaged by GERMAN SUBMARINE U-564 at 27.03°N, -80.05°W (2 of 36 crewmen perished)
 * 5 May – The United States freighter Afoundria sunk by U-108 at 20°N, -73.5°W
 * 5 May – The United States tanker Java Arrow damaged by GERMAN SUBMARINE U-333 at 27.5°N, -80.13°W (2 of 47 crewmen perished)
 * 6 May – The United States tanker Halsey sunk by U-333 at 27.23°N, -80.05°W (5 of 28 crewmen perished)
 * 6 May – The United States freighter Alcoa Puritan sunk by U-507 at 28.67°N, -88.37°W
 * 8 May – The United States freighter Ohioan sunk by U-564 at 26.52°N, -79.97°W (15 of 37 crewmen perished)
 * 10 May – The United States tanker Aurora damaged by U-506 at 28.58°N, -90°W (1 of 50 crewmen perished)
 * 12 May – The United States tanker Virginia sunk by U-507 at 28.88°N, -89.48°W (27 of 41 crewmen perished)
 * 13 May – The United States tanker Gulfprince damaged by U-507 at 28.53°N, -91°W
 * 13 May – The United States tanker Gulfpenn sunk by U-506 at 28.48°N, -89.2°W (13 of 38 crewmen perished)
 * 13 May – The United States freighter David McKelvy sunk by U-506 at 28.5°N, -89.92°W (17 of 36 crewmen perished)
 * 15 May – The United States freighter Nicarao sunk by U-751 at 25.33°N, -74.32°W (8 of 39 crewmen perished)
 * 16 May – The United States tanker Sun damaged by U-506 at 28.68°N, -90.32°W
 * 16 May – The United States tanker William C. McTarnahan damaged by U-506 at 28.87°N, -90.33°W (18 of 38 crewmen perished)
 * 16 May – The United States tanker Gulfoil sunk by U-506 at 28.68°N, -90.32°W (21 of 40 crewmen perish)
 * 19 May – The United States freighter Heredia sunk by U-506 at 27.53°N, -91°W (36 of 62 crewmen perished)
 * 19 May – The United States freighter Ogontz sunk by U-103 at 23.5°N, -86.62°W (19 of 41 crewmen perished)
 * 20 May – The United States tanker Halo sunk by U-506 at 28.7°N, -90.13°W (21 of 42 crewmen perished)
 * 20 May – The United States freighter George Calvert sunk by U-752 at 22.92°N, -84.43°W (3 of 61 crewmen perished)
 * 21 May – The United States freighter Plow City sunk by U-588 at 39.13°N, -69.95°W (1 of 30 crewmen perished)
 * 26 May – The United States tanker Carrabulle sunk by U-106 at 26.15°N, -89.35°W (22 of 40 crewmen perished)
 * 26 May – The United States freighter Atenas damaged by U-106 at 25.84°N, -89.08°W
 * 30 May – The United States freighter Alcoa Shipper sunk by GERMAN SUBMARINE U-404 at 37.82°N, -65.25°W (7 of 32 crewmen perished)
 * 1 June – The United States freighter West Notus sunk by U-404 at 34.16°N, -68.33°W (4 of 40 crewmen perished)
 * 1 June – The United States freighter Hampton Roads sunk by U-106 at 23°N, -85.7°W (5 of 28 crewmen perished)
 * 3 June – The United States freighter M.F. Elliott sunk by GERMAN SUBMARINE U-502 off the Florida Keys (13 of 45 crewmen perished)
 * 10 June – The United States tanker Hagan sunk by U-157 at 22°N, -77.5°W (6 of 44 crewmen perished)
 * 12 June – The United States tanker Cities Service Toledo sunk by U-158 at 29.03°N, -91.98°W (15 of 45 crewmen perished)

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 corvettes 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:


 * GERMAN SUBMARINE U-85: sunk on 14 April by the destroyer USS Roper (DD-147) in position 35.917°N, -75.217°W off Cape Hatteras, the first sinking in U.S. waters
 * GERMAN SUBMARINE U-352: sunk on 9 May by the cutter USS Icarus in position 34.2°N, -76.583°W off Cape Hatteras
 * GERMAN SUBMARINE U-157: sunk on 13 June by the cutter USS Thetis in position 24.217°N, -82.05°W off Havana, Cuba
 * GERMAN SUBMARINE U-158: sunk on 30 June by a Mariner aircraft (USN VP-74) in position 32.833°N, -67.467°W west of Bermuda
 * GERMAN SUBMARINE U-215: sunk on 3 July by the Armed ASW Trawler HMS Le Tiger in position 41.48°N, -66.38°W by depth charges
 * GERMAN SUBMARINE U-701: sunk on 7 July by a Lockheed Hudson aircraft in position 34.833°N, -74.917°W off Cape Hatteras
 * GERMAN SUBMARINE U-153: sunk on 13 July by the destroyer USS Lansdowne in position 9.933°N, -81.483°W off Colón, Panama
 * GERMAN SUBMARINE U-576: sunk on 15 July by two Kingfisher aircraft and ramming by the U.S. motor vessel Unicoi in position 34.85°N, -75.367°W off Cape Hatteras
 * GERMAN SUBMARINE U-166: sunk on 30 July by the US Navy patrol craft, PC 566, in position 28.517°N, -90.75°W in the Gulf of Mexico, the only U-boat sunk in the Gulf of Mexico during World War II