Battle of the Atlantic
The Battle of the Atlantic, the longest continuous military campaign[11][12] in World War II, ran from 1939 to the defeat of Nazi Germany in 1945, covering a major part of the naval history of World War II. At its core was the Allied naval blockade of Germany, announced the day after the declaration of war, and Germany's subsequent counter-blockade. The campaign peaked from mid-1940 through to the end of 1943.
For the Atlantic naval campaign of World War I, see Atlantic U-boat campaign of World War I.
The Battle of the Atlantic pitted U-boats and other warships of the German Kriegsmarine (Navy) and aircraft of the Luftwaffe (Air Force) against the Royal Navy, Royal Canadian Navy, United States Navy, and Allied merchant shipping. Convoys, coming mainly from North America and predominantly going to the United Kingdom and the Soviet Union, were protected for the most part by the British and Canadian navies and air forces. These forces were aided by ships and aircraft of the United States beginning September 13, 1941.[13] The Germans were joined by submarines of the Italian Regia Marina (Royal Navy) after Germany's Axis ally Italy entered the war on June 10, 1940.
As an island country, the United Kingdom was highly dependent on imported goods. Britain required more than a million tons of imported material per week in order to survive and fight. In essence, the Battle of the Atlantic involved a tonnage war; the Allied struggle to supply Britain, and the Axis attempt to stem the flow of merchant shipping that enabled Britain to keep fighting. Rationing in the United Kingdom was also used with the aim of reducing demand, by reducing wastage and increasing domestic production and equality of distribution. From 1942 onward, the Axis also sought to prevent the build-up of Allied supplies and equipment in the UK in preparation for the invasion of occupied Europe. The defeat of the U-boat threat was a prerequisite for pushing back the Axis in Western Europe. The outcome of the battle was a strategic victory for the Allies—the German tonnage war failed—but at great cost: 3,500 merchant ships and 175 warships were sunk in the Atlantic for the loss of 783 U-boats and 47 German surface warships, including 4 battleships (Bismarck, Scharnhorst, Gneisenau, and Tirpitz), 9 cruisers, 7 raiders, and 27 destroyers. This front ended up being highly significant for the German war effort: Germany spent more money on producing naval vessels than it did every type of ground vehicle combined, including tanks.[14]
The Battle of the Atlantic has been called the "longest, largest, and most complex" naval battle in history.[15] The campaign started immediately after the European war began, during the so-called "Phoney War", and lasted more than five years, until the German surrender in May 1945. It involved thousands of ships in a theatre covering millions of square miles of ocean. The situation changed constantly, with one side or the other gaining advantage, as participating countries surrendered, joined and even changed sides in the war, and as new weapons, tactics, counter-measures and equipment were developed by both sides. The Allies gradually gained the upper hand, overcoming German surface-raiders by the end of 1942 and defeating the U-boats by mid-1943, though losses due to U-boats continued until the war's end. British Prime Minister Winston Churchill later wrote "The only thing that really frightened me during the war was the U-boat peril. I was even more anxious about this battle than I had been about the glorious air fight called the 'Battle of Britain'."[16]
Name[edit]
On 5 March 1941, the First Lord of the Admiralty, A. V. Alexander, asked Parliament for "many more ships and great numbers of men" to fight "the Battle of the Atlantic", which he compared to the Battle of France, fought the previous summer. [17] The first meeting of the Cabinet's "Battle of the Atlantic Committee" was on March 19.[18] Churchill claimed to have coined the phrase "Battle of the Atlantic" shortly before Alexander's speech,[19] but there are several examples of earlier usage.[e]
Background[edit]
Following the use of unrestricted submarine warfare by Germany in the First World War, countries tried to limit or abolish submarines. The effort failed. Instead, the London Naval Treaty required submarines to abide by "cruiser rules", which demanded they surface, search[20] and place ship crews in "a place of safety" (for which lifeboats did not qualify, except under particular circumstances)[21] before sinking them, unless the ship in question showed "persistent refusal to stop...or active resistance to visit or search".[22] These regulations did not prohibit arming merchantmen,[23] but doing so, or having them report contact with submarines (or raiders), made them de facto naval auxiliaries and removed the protection of the cruiser rules.[24]
The Treaty of Versailles forbade the Germans to operate U-boats and reduced the German surface fleet to a few obsolete ships. When three of these obsolete ships had to be replaced, the Germans opted to construct the Deutschland-class of panzerschiffe ( armoured ships ) or "pocket battleships" as they were nicknamed by foreign navies. These ships were designed for commerce raiding on distant seas, to operate as a raider hunting for independently sailing ships, and to avoid combat with superior forces.[25]
The Anglo-German Naval Agreement of 1935 allowed Hitler to renounce the treaty of Versailles, and to build a fleet 35% the size of Britain's fleet. A building program for four battleships, two aircraft carriers, five heavy cruisers, destroyers and U-boats was immediately initiated. With the agreement, Hitler thought that conflict with the UK was very unlikely and hence the fleet was designed for commerce raiding against the French rather than to try to challenge command of the sea.[26][27] The commander of the German U-boats, Karl Dönitz, had his own opinions. In contrast with Hitler and Raeder, the chief of the German Navy, he judged that war with the UK was inevitable and that not a large surface fleet was needed, but that U-boats could defeat the British. According to his calculations, a fleet of 300 medium Type VII U-boats could sink a million tons of ships a month and within a year sink enough of the about 3,000 British merchant ships ( comprising 17,5 million tons ) in order to strangle the British economy.[28][29][30] In the first world war, U-boats had been defeated mainly by the convoy system, but Dönitz thought this could be overcome with the Rudeltaktik: a patrol line of U-boats searched for a convoy and when one was found all U-boats converged and attacked together at night on the surface.[31] Aircraft nor ASDIC were considered a serious threat at the time: ASDIC could not detect a surfaced submarine and its range was less than that of an elektric torpedo, aircraft could not operate at night and during day an alert U-boat could dive before the aircraft attacked.[32] Dönitz could not convince Raeder of his ideas, each time the U-boat fleet was expanded, Raeder opted to build a mixture of coastal, medium and large submarines, even minelayers and U-cruisers. Even when in 1938 Hitler realised he would sooner or later have to oppose the UK and launched his Plan Z, only a minority of the planned 239 U-boats were medium U-boats.[33]
The German occupation of Norway in April 1940, the rapid conquest of the Low Countries and France in May and June, and the Italian entry into the war on the Axis side in June transformed the war at sea in general and the Atlantic campaign in particular in three main ways:
The completion of Hitler's campaign in Western Europe meant U-boats withdrawn from the Atlantic for the Norwegian campaign now returned to the war on trade. So at the very time the number of U-boats on patrol in the Atlantic began to increase, the number of escorts available for the convoys was greatly reduced.[47] The only consolation for the British was that the large merchant fleets of occupied countries like Norway and the Netherlands came under British control. After the German occupation of Denmark and Norway, Britain occupied Iceland and the Faroe Islands, establishing bases there and preventing a German takeover.
It was in these circumstances that Winston Churchill, who had become Prime Minister on 10 May 1940, first wrote to President Franklin Roosevelt to request the loan of fifty obsolescent US Navy destroyers. This eventually led to the "Destroyers for Bases Agreement" (effectively a sale but portrayed as a loan for political reasons), which operated in exchange for 99-year leases on certain British bases in Newfoundland, Bermuda and the West Indies, a financially advantageous bargain for the United States but militarily beneficial for Britain, since it effectively freed up British military assets to return to Europe. A significant percentage of the US population opposed entering the war, and some American politicians (including the US Ambassador to Britain, Joseph P. Kennedy) believed that Britain and its allies might actually lose. The first of these destroyers were only taken over by their British and Canadian crews in September, and all needed to be rearmed and fitted with ASDIC. It was to be many months before these ships contributed to the campaign.
[edit]
United Kingdom[edit]
During the Second World War nearly one third of the world's merchant shipping was British. Over 30,000 men from the British Merchant Navy died between 1939 and 1945. More than 2,400 British ships were sunk. The ships were crewed by sailors from all over the British Empire, including some 25% from India and China, and 5% from the West Indies, Middle East and Africa. The British officers wore uniforms very similar to those of the Royal Navy. The ordinary sailors, however, had no uniform and when on leave in Britain they sometimes suffered taunts and abuse from civilians who mistakenly thought the crewmen were shirking their patriotic duty to enlist in the armed forces. To counter this, the crewmen were issued with an 'MN' lapel badge to indicate they were serving in the Merchant Navy.
The British merchant fleet was made up of vessels from the many and varied private shipping lines, examples being the tankers of the British Tanker Company and the freighters of Ellerman and Silver Lines. The British government, via the Ministry of War Transport (MoWT), also had new ships built during the course of the war, these being known as Empire ships.
United States[edit]
In addition to its existing merchant fleet, United States shipyards built 2,710 Liberty ships totalling 38.5 million tons, vastly exceeding the 14 million tons of shipping the German U-boats were able to sink during the war.
Canada[edit]
Information obtained by British agents regarding German shipping movements led Canada to conscript all its merchant vessels two weeks before actually declaring war, with the Royal Canadian Navy taking control of all shipping August 26, 1939. At the outbreak of the war, Canada possessed 38 ocean-going merchant vessels. By the end of hostilities, in excess of 400 cargo ships had been built in Canada. More than 70 Canadian merchant vessels were lost. An estimated 1,500 merchant sailors were killed, including eight women.[139]
At the end of the war, Rear Admiral Leonard Murray, Commander-in-Chief Canadian North Atlantic, remarked, "...the Battle of the Atlantic was not won by any Navy or Air Force, it was won by the courage, fortitude and determination of the British and Allied Merchant Navy."[140]
Norway[edit]
Before the war, Norway's Merchant Navy was the fourth largest in the world and its ships were the most modern. The Germans and the Allies both recognised the great importance of Norway's merchant fleet, and following Germany's invasion of Norway in April 1940, both sides sought control of the ships. Norwegian Nazi puppet leader Vidkun Quisling ordered all Norwegian ships to sail to German, Italian or neutral ports. He was ignored. All Norwegian ships decided to serve at the disposal of the Allies. The vessels of the Norwegian Merchant Navy were placed under the control of the government-run Nortraship, with headquarters in London and New York.
Nortraship's modern ships, especially its tankers, were extremely important to the Allies. Norwegian tankers carried nearly one-third of the oil transported to Britain during the war. Records show that 694 Norwegian ships were sunk during this period, representing 47% of the total fleet. At the end of the war in 1945, the Norwegian merchant fleet was estimated at 1,378 ships. More than 3,700 Norwegian merchant seamen died.
Assessment[edit]
It is maintained by G. H. Persall[141] that "the Germans were close" to economically starving England, but they "failed to capitalize" on their early war successes. Others, including Blair[142] and Alan Levine, disagree; Levine states this is "a misperception", and that "it is doubtful they ever came close" to achieving this.[143]
The focus on U-boat successes, the "aces" and their scores, the convoys attacked, and the ships sunk, serves to camouflage the Kriegsmarine's manifold failures. In particular, this was because most of the ships sunk by U-boats were not in convoys, but sailing alone, or having become separated from convoys.
At no time during the campaign were supply lines to Britain interrupted; even during the Bismarck crisis, convoys sailed as usual (although with heavier escorts). In all, during the Atlantic campaign only 10% of transatlantic convoys that sailed were attacked, and of those attacked only 10% on average of the ships were lost. Overall, more than 99% of all ships sailing to and from the British Isles during World War II did so successfully.
Despite their efforts, the Axis powers were unable to prevent the build-up of Allied invasion forces for the liberation of Europe. In November 1942, at the height of the Atlantic campaign, the US Navy escorted the Operation Torch invasion fleet 3,000 mi (4,800 km) across the Atlantic without hindrance, or even being detected. In 1943 and 1944 the Allies transported some 3 million American and Allied servicemen across the Atlantic without significant loss. By 1945 the USN was able to wipe out a wolf-pack suspected of carrying V-weapons in the mid-Atlantic, with little difficulty.
Third, and unlike the Allies, the Germans were never able to mount a comprehensive blockade of Britain. Nor were they able to focus their effort by targeting the most valuable cargoes, the eastbound traffic carrying war materiel. Instead they were reduced to the slow attrition of a tonnage war. To win this, the U-boat arm had to sink 300,000 GRT per month in order to overwhelm Britain's shipbuilding capacity and reduce its merchant marine strength.
In only four out of the first 27 months of the war did Germany achieve this target, while after December 1941, when Britain was joined by the US merchant marine and ship yards the target effectively doubled. As a result, the Axis needed to sink 700,000 GRT per month; as the massive expansion of the US shipbuilding industry took effect this target increased still further. The 700,000 ton target was achieved in only one month, November 1942, while after May 1943 average sinkings dropped to less than one tenth of that figure.
By the end of the war the Allies had built over 38 million tons of new shipping.
The reason for the misperception that the German blockade came close to success may be found in post-war writings by both German and British authors. Blair attributes the distortion to "propagandists" who "glorified and exaggerated the successes of German submariners", while he believes Allied writers "had their own reasons for exaggerating the peril".[142]
Dan van der Vat suggests that, unlike the US, or Canada and Britain's other dominions, which were protected by oceanic distances, Britain was at the end of the transatlantic supply route closest to German bases; for Britain it was a lifeline. It is this which led to Churchill's concerns.[144] Coupled with a series of major convoy battles in the space of a month, it undermined confidence in the convoy system in March 1943, to the point Britain considered abandoning it,[145] not realising the U-boat had already effectively been defeated. These were "over-pessimistic threat assessments", Blair concludes: "At no time did the German U-boat force ever come close to winning the Battle of the Atlantic or bringing on the collapse of Great Britain".[146]