Battle of the Atlantic II
The Battle of the Atlantic, actually a campaign extending for the duration of World War II (1939–1945), was one of the key contests of the entire war. Without victory here, Britain would have been forced to sue for peace, and no invasion of the European continent via the English Channel would have been possible. The Germans waged the battle with some surface raiders, the most notorious of which was the battleship Bismarck (sunk on May 27, 1941), but chiefly they employed submarines. Italian submarines also took part. The decisive point came in the spring of 1943
The Battle of the Atlantic was a grim no-holds-barred struggle. Vessels were torpedoed without warning and often at night. Chances of crew survival were slight, especially in the case of tankers, the primary U-boat targets. Death might come with the explosion of a torpedo striking the ship or from subsequent internal blasts. Crewmen might be trapped below decks as the mortally wounded ship sank. Burning oil extending hundreds of yards from a vessel lengthened the odds of survival. If there was time to man the lifeboats, crew members might find themselves face to face with the U-boat that had sunk them as it surfaced to survey the destruction. Some U-boat captains provided assistance, but there were also reports of lifeboats and survivors in the water being gunned down. Other ships in the convoy could not stop to assist survivors, lest they themselves become targets.
On the outbreak of war, the Allies had promptly reinstituted the convoy system of World War I (1914–1918). Convoys were predicated on reducing the number of targets and the assumption that the more targets there were, the more likely they were to be found. In the convoys, numbers of merchant ships traveled together, with escorting destroyers and destroyer escorts patrolling the flanks. The U-boats would still get their kills, but the percentage of losses was significantly less, and the attackers ran the risk of being hunted down and sunk by the escorting surface warships.
Early in the war commander of German submarines Vizeadmiral Karl Dönitz had few boats. German leader Adolf Hitler had wanted a balanced navy, and Grossadmiral Eric Raeder had been busy building just that. For the German Navy at least, the war came three or four years too early. Germany began the war with 56 U-boats, only a slight improvement from the numbers of August 1914. Despite a shift from surface ship construction to building U-boats, only 37 new U-boats were commissioned in the first year of the war; the earlier plan had been to build 100 in that time frame.
It was 1941 before the U-boat construction program really got going. Although 230 new U-boats were under construction in April, only 32 were available for operations that month. Dönitz asserted that he would have won the Battle of the Atlantic in 1941 or 1942 had he possessed, at the beginning of the war, the 300 U-boats he deemed necessary. It is probably a false claim, for a higher rate of sinking of merchantmen would certainly have forced the Allies to shift military assets to the struggle, including long-range aircraft to Coastal Command, earlier than was the case.
Dönitz’s submarines also lacked effective radar until near the end of the war, and they struggled—at least in the first year—with defective torpedoes. Dönitz believed that this cost at least two U-boats in premature explosions and that faulty magnetic torpedo detonators prevented the sinking of the British battleships Ark Royal and Nelson.
Dönitz developed new tactics, the most important of which was the Rudeltaktik (Wolf Tactic, known to the Allies as the Wolf Pack). Groups of up to 15–20 submarines would spread out along the Atlantic sea-lanes. Merchantmen traveling alone would be immediately attacked; in the event of a convoy sighting, the submarine would shadow it and radio for reinforcements. The closest U-boats would then converge for a night surface attack, which would maximize confusion for the defenders and minimize the possibility of submarine detection. The submarines would then submerge and reorganize for a second attack.
To enable his submarines to remain on station for longer periods, Dönitz sent out milk-cow supply submarines. The German Navy’s B-Dienst intelligence service also broke the British convoy codes, enabling Dönitz to direct his boats to where he believed enemy ships would be. The Germans also used aircraft, particularly the long-range Focke-Wolfe Fw-200, with considerable effectiveness against Allied convoys in the eastern Atlantic within range of German air bases. Yet Dönitz was handicapped because Luftwaffe commander Reichsmarschall Hermann Göring would not provide planes to reconnoiter at sea, and Hitler often ordered the Uboats to undertake missions for which they were not designed.
The British received an important assist in May 1941 when the U.S. Navy began escorting convoys between the United States and Iceland. In June 1941 Canada created the Canadian Escort Force for the same purpose. Indeed, the Royal Canadian Navy (RCN) played a key role in the struggle. Comprising only 6 destroyers and 5 minesweepers at the beginning of the war, the RCN grew by war’s end to 2 light carriers, 2 light cruisers, 15 destroyers, 60 frigates, 118 corvettes, and many other vessels. Virtually all these ships were committed to the Battle of the Atlantic.
By June 1941 the Germans had sent to the bottom some 5.7 million tons of Allied shipping, with British shipyards able to launch only 800,000 replacement tons. Large Italian submarines, a number of them operating out of Bordeaux, also sank 500,000 tons of shipping in the course of the war. A significant increase in U-boat strength enabled the Germans to virtually control the Atlantic for more than a year after America’s entry into the war.
Beginning in February 1942 in Operation paukenschlag (drumbeat), Dönitz sent 19 U-boats to the U.S. Atlantic coast. These found easy pickings, with tankers and other ships sailing alone and the U.S. shoreline brightly illuminated at night. The U-boats sank 81 ships. Finally the United States organized coastal convoys, and in May Dönitz redirected his submarines southward. Dönitz was then aided by the initiation of British and American convoys in the Arctic to the Soviet Union, which diluted their ability to protect convoys in the Atlantic. He also dispatched some large U-boats into the South Atlantic and the Indian Ocean, but supply problems and attacks by surface ships led to their recall. Dönitz was aided by the dispersal of Allied warships to protect the initiation of British and American convoys in the Arctic to the Soviet Union.
By August 1942 Dönitz had 300 submarines at his disposal. The effect of this increase was augmented when, the month before, Germany changed its naval codes. This opened the critical period in the struggle for control of the Atlantic.
In January 1943 Hitler, displeased by the lack of results from his capital ships, sacked Raeder and appointed Dönitz to head the navy. Dönitz intensified the Uboat war, and early in the year the toll of Allied shipping falling prey to submarines rose precipitously. By March, Britain had food reserves sufficient only for three months. By May, half of the world’s 5,600 merchant ships of 1939 had been lost. But large, fast, unescorted converted luxury liners could outrun U-boats and make the trip safely, as could heavily protected troop transports.
Although experts disagree, the turning point in the Battle of the Atlantic probably came with Royal Navy commander Peter W. Gretton’s ONS-1 convoy. From April 28 to May 6, 1943, Gretton’s 46 merchant ships steamed across the North Atlantic, dueling with 51 U-boats. Gretton lost 13 of his ships, but 7 U-boats were sunk (5 by escorts and 2 by aircraft).
The Allies were on the offensive thereafter. Coastal Command aircraft, equipped with lightweight 10-centimeter radar and working in conjunction with Royal Navy corvettes, attacked U-boats entering and leaving French bases in the Bay of Biscay. In May 1943 Dönitz lost 38 U-boats, a dozen more than were built; at the same time only 41 merchantmen were lost. In June the U.S. Navy Tenth Fleet began operating hunter-killer teams in the Atlantic, and in October 1943 the Allies acquired air bases in the Azores from Portugal.
Aircraft proved vital; they could deflect German bomber attacks and do battle with surfaced submarines before they could dive. One solution was to send fighter aircraft along with a convoy, and the British equipped a number of merchantmen with a forward catapult that held a modified Hurricane fighter. After launch and intercept, the fighter would try to make landfall or else land in the water.
A far more satisfactory solution was to fit a flight deck to a merchant ship hull. The German cargo-passenger ship Hannover, taken in the West Indies in March 1940, became the first escort carrier, entering service in June 1941 as the flushdeck aircraft carrier Audacity, with six fighters. Additional escort carriers appeared in the form of U.S.-built conversions on C-3 hulls from the Maritime Commission: the Archer and the Avenger-class ships.
Originally contracted by the Royal Navy, they were transferred under Lend-Lease and entered service in the first half of 1942. Designed for 15 aircraft each, these escort carriers (CVEs or Jeep carriers) were slow (16.5 knots), but they proved invaluable. U.S. CVE captains had complete freedom of action to mount hunt-andkill missions. Teams composed of an escort carrier and half a dozen destroyers or new destroyer escorts sank 53 U-boats and captured another; they were probably the single most important U.S. contribution to the struggle against the U-boats.
Long-range aircraft were essential in closing the Mid-Atlantic gap, but the RAF’s preoccupation with strategic bombing meant that Coastal Command possessed few aircraft suitable for this purpose. Bomber Command’s air marshal Arthur Harris finally made air assets available. The U.S. Consolidated PBY Catalina and PB2Y Coronado and the British Short Sunderland flying boats proved invaluable, as did long-range B-24 Liberator and British Lancaster bombers.
Finally, in August 1944 RAF Bomber Command Squadron 617 (the “Dam Busters”) began attacks with specially designed Tallboy bombs against the concrete- reinforced U-boat pens of the Bay of Biscay. U-boats in port were now vulnerable, and in the last year of the war 57 U-boats were destroyed by bombing, compared with only five in the previous five years. This shows what might have been accomplished had the bombers been directed against the submarines earlier. Indeed, after March 1943 aircraft were probably the chief factor in the defeat of the U-boats. Between March 1943 and May 1945 a total of 590 U-boats were destroyed, compared to only 194 in the previous three and a half years of war. Of these, 290 were by aircraft, 174 by ships, and the remainder through a combination of the two or other causes.
In the first few months of 1945, Dönitz sent to sea new snorkel-equipped Uboats that were able to operate submerged while at the same time taking in air from the surface. During January to April these sank some 253,000 tons of Allied shipping, most of it in waters around the British Isles. The Allies countered with hunterkiller teams of destroyer escorts and escort carriers. The last German submarine sinking of an Allied merchant ship occurred on May 6, 1945.In the 69-month Battle of the Atlantic, the longest campaign of the war, German U-boats sank 2,850 Allied and neutral merchant ships, 2,520 of them in the Atlantic and Indian oceans, as well as many warships, from aircraft carriers to destroyers and smaller ships. The Germans lost 1 large battleship, 1 pocket battleship, some armed merchant raiders, and 650 U-boats, 522 of them in the Atlantic and Indian oceans.
Doenitz, Karl. Memoirs: Ten Years and Twenty Days. Translated by R. H. Stevens in collaboration with David Woodward. Annapolis, MD: Naval Institute Press, 1990.
German, Tony. The Sea Is at Our Gates: The History of the Canadian Navy. Toronto: McClelland and Stewart, 1990.
Middlebrook, Martin. Convoy. New York: William Morrow, 1977.
Padfield, Peter. Dönitz: The Last Führer, Portrait of a Nazi War Leader. New York: Harper and Row, 1984.
Y’Blood, William T. Hunter-Killer: U.S. Escort Carriers in the Battle of the Atlantic. Annapolis, MD: Naval Institute Press, 1983.