U-boats withdrawn from the US coast

On 19 July 1942 the commander of the German U-boat arm, Admiral Karl Dönitz, recalled from the Cape Hatteras area the last two boats still operating off the Atlantic coast of the United States, U-754 and U-458 – at least, that is how the American historian Clay Blair and the uboat.net website identify them. This ended the campaign that had opened half a year earlier with Operation Drumbeat (Paukenschlag) and that German crews called the “second happy time”. The Germans had not been driven out of the western Atlantic. The east coast of America, however, had ceased to pay, and Dönitz, faithful to the principle of the “tonnage war”, moved his boats to where it was easier to sink ships.

From the Bucket Brigade to convoys

In the spring of 1942 the Americans gradually made up lost ground. From April ships sailed along the coast by day, in short hops between protected anchorages, in what was called the Bucket Brigade. The coast was dimmed, and the sinking of U-85 by the destroyer USS Roper on 14 April showed that U-boats could not operate there with impunity. The breakthrough, however, was the introduction of proper convoys. On 14 May the first coastal convoy sailed from Hampton Roads to Key West, and soon convoys were also running regularly between Hampton Roads and New York and further north, to Boston and Halifax. In the summer the system began to be linked into a network of interlocking routes, so that a ship could make the whole voyage from the Caribbean to New York under escort. The full system, with hubs at New York and Guantánamo Bay, did not start operating until the end of August.

Equally important was what happened in the air. Over the shipping lanes flew navy and army patrol aircraft, seaplanes, navy airships from bases in New Jersey and North Carolina, and civilian aircraft of the Civil Air Patrol, some of them armed with bombs. An aircraft rarely sank a U-boat, but it forced it to dive, and a submerged boat was slow and blind. Crews reported that by day they could not surface without risking air attack, and by night they came upon ships sailing in formation under escort.

German losses in July

At the turn of June and July the defences began to take their toll. On 3 July the minelayer U-215 under Kapitänleutnant Fritz Hoeckner, sent to lay mines off Boston, torpedoed the American Liberty ship Alexander Macomb from one of the convoys in the waters between New England and Nova Scotia. The British armed trawler HMS Le Tiger of the escort found the U-boat and sank it with depth charges. Its entire crew of nearly fifty was lost. The wreck was not found until 2004.

Four days later, on 7 July, off Cape Hatteras, the crew of a twin-engined Lockheed Hudson of the Army Air Forces’ 396th Bombardment Squadron caught Kapitänleutnant Horst Degen’s U-701 on the surface. In June this boat had laid mines at the entrance to Chesapeake Bay, which damaged several vessels, and at the end of the month it had sunk the tanker William Rockefeller off Hatteras. Hit by two bombs, U-701 sank. Seventeen men escaped from the hull, but after almost two days in the water, with no boat and no drinking water, only seven were still alive, including Degen. They were found and picked up by a US Coast Guard seaplane.

On 15 July, again off North Carolina, Kapitänleutnant Hans-Dieter Heinicke’s U-576 attacked convoy KS-520, bound from Hampton Roads to Key West. It sank the Nicaraguan freighter Bluefields and damaged two other ships, but after firing its salvo it accidentally broached in the middle of the convoy. The gun crew of the American merchant ship Unicoi opened fire on it, and two Vought OS2U Kingfisher seaplanes dropped depth charges. The boat went down with all 45 of her crew. Her wreck, lying more than 200 metres down some 30 nautical miles off Hatteras, was found in 2014 by an expedition of the American ocean agency NOAA, a few hundred metres from the wreck of Bluefields. The day before, a Coast Guard aircraft had damaged U-402 with depth charges.

In all, according to uboat.net’s figures, seven U-boats were sunk during the six-month campaign in American waters, from the coast of New England to the Caribbean. U-85, U-352, U-701 and U-576 were lost off the east coast of the United States, the rest further south. Only members of the crews of U-352 and U-701 survived. In itself this was not much, but the July losses, combined with dwindling successes, settled Dönitz’s decision.

Dönitz’s decision

From the outset Dönitz treated American waters as the best hunting ground of the moment, not as an end in itself. What counted in his calculations was how many tons an average boat sank per day on patrol. From May that figure fell rapidly off the east coast. Ships sailed in convoys, often close inshore, in shallow waters where a submerged boat was easy to detect and hard to hide, with aircraft circling overhead. Sinking lone tankers silhouetted against the lights of coastal towns was a thing of the past, and the risk of losing a boat had clearly increased. Earlier, in the spring, the weight of the campaign had shifted to the Caribbean and the Gulf of Mexico. By mid-July only two boats were left off the coast of the United States.

It is often written that Dönitz withdrew the last U-boats “in response to the increasingly effective American convoy system”. That is an accurate shorthand. It needs only to be supplemented by the growing role of air power, and by the fact that the withdrawal concerned only the US east coast. U-754 did not head straight home but went north. On 28 July, off Cape Sable in Nova Scotia, it machine-gunned the American fishing trawler Ebb, killing five fishermen. On 31 July, south of Yarmouth, it was spotted by a Royal Canadian Air Force Hudson and sunk with depth charges. Its entire crew of 43 was lost. U-boats continued to operate in Canadian waters: in July U-132 was attacking convoys in the Gulf of St Lawrence.

The toll of the “second happy time”

The figures depend on which waters and which period a tally covers. According to frequently cited calculations, in the first half of 1942 U-boats sank 397 ships of more than 2 million gross register tons in waters guarded by the Americans, including the Gulf of Mexico and the Caribbean. Some 5,000 people were killed, most of them merchant seamen. Broader tallies, covering January–August 1942 and the whole of the western Atlantic, speak of more than 600 ships and about 3 million tons, at a cost of 22 U-boats. The waters off North Carolina alone, known as “Torpedo Alley”, hold more than 80 wrecks from that period, according to the US National Park Service. The Germans’ own losses were disproportionately small. For the Allies it was the worst period of the entire Battle of the Atlantic.

Place in the war

The withdrawal of the U-boats from the coast of the United States did not mean the end of the threat in the western Atlantic. In the summer and autumn of 1942 Dönitz’s boats reaped a rich harvest in the Caribbean, especially around Trinidad, from where tankers and bauxite ore carriers sailed, and also off the coasts of Brazil and West Africa. The sinking of several Brazilian passenger ships in August led Brazil to declare war on Germany and Italy on 22 August 1942.

Above all, however, Dönitz returned to the convoys of the North Atlantic. He had more and more boats, as the shipyards were delivering a dozen or more a month, sometimes over twenty, and the Type XIV supply submarines allowed wolf packs to patrol the mid-ocean for long periods. There, in the “air gap” beyond the reach of aircraft from North America, Iceland and Britain, the convoys were protected only by their escort ships. As early as the turn of July and August wolf packs struck convoys ON 115 and SC 94, and in the autumn and winter of 1942–1943 the convoy battles in the mid-Atlantic reached their greatest intensity. They were decided only in May 1943, when Allied long-range aircraft, escort carriers, radar and the reading of German ciphers turned the tide of the battle.

The summer of 1942 on America’s east coast showed that these same means worked: a convoy with an escort and an aircraft overhead robbed submarines of their advantage. The lesson that the British had learned in 1939–1941 the US Navy absorbed half a year late and at the cost of hundreds of ships.