31.4.2: Conflict in the Atlantic

The Battle of the Atlantic was the longest continuous military campaign in World War II, running from 1939 to the defeat of Germany in 1945. At its core was the Allied naval blockade of Germany, announced the day after the declaration of war, and Germany’s subsequent counter-blockade. This battle peaked from mid-1940 through to the end of 1943. The Battle of the Atlantic pitted U-boats and other warships of the Kriegsmarine (German navy) and aircraft of the Luftwaffe (German Air Force) against the Royal Canadian Navy, Royal Navy, United States Navy, and Allied merchant shipping. The convoys, mainly from North America and going to the United Kingdom and the Soviet Union, were primarily 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 from September 13, 1941. The Germans were joined by submarines of the Italian Royal Navy (Regia Marina) after their Axis ally Italy entered the war on June 10, 1940.

As an island nation, the United Kingdom was dependent on imported goods. Britain required more than a million tons of imported material per week in order to be able to survive and fight. In essence, the Battle of the Atlantic was 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. From 1942 on, the Germans sought to prevent the build-up of Allied supplies and equipment in the British Isles in preparation for the invasion of occupied Europe. The defeat of the U-boat threat was a prerequisite for pushing back the Germans. Winston Churchill later wrote,

The Battle of the Atlantic was the dominating factor all through the war. Never for one moment could we forget that everything happening elsewhere, on land, at sea or in the air depended ultimately on its outcome.— Winston ChurchillThe outcome of the battle was a strategic victory for the Allies—the German blockade failed—but at great cost: 3,500 merchant ships and 175 warships were sunk for the loss of 783 U-boats.

The name “Battle of the Atlantic” was coined by Winston Churchill in February 1941. It has been called the “longest, largest, and most complex” naval battle in history. It involved thousands of ships in more than 100 convoy battles and perhaps 1,000 single-ship encounters, in a theater covering thousands 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, 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 war’s end.

Early Skirmishes

In 1939, the Kriegsmarine lacked the strength to challenge the combined British Royal Navy and French Navy for command of the sea. Instead, German naval strategy relied on commerce raiding using capital ships, armed merchant cruisers, submarines, and aircraft. Many German warships were already at sea when war was declared, including most of the available U-boats and the “pocket battleships” which sortied into the Atlantic in August. These ships immediately attacked British and French shipping. U-30 sank the ocean liner SS Athenia within hours of the declaration of war in breach of her orders not to sink passenger ships. The U-boat fleet which dominated so much of the Battle of the Atlantic was small at the beginning of the war; many of the 57 available U-boats were the small and short-range Type IIs, useful primarily for mine laying and operations in British coastal waters. Much of the early German anti-shipping activity involved mine laying by destroyers, aircraft, and U-boats off British ports.

With the outbreak of war, the British and French immediately began a blockade of Germany, although this had little immediate effect on German industry. The Royal Navy quickly introduced a convoy system for the protection of trade that gradually extended out from the British Isles, eventually reaching as far as Panama, Bombay, and Singapore. Convoys allowed the Royal Navy to concentrate its escorts near the one place the U-boats were guaranteed to be found, the convoys. Each convoy consisted of between 30 and 70 mostly unarmed merchant ships.

U-Boat Strategy

Early in the war, Dönitz submitted a memorandum to Grand Admiral Erich Raeder, the German navy’s Commander-in-Chief, in which he estimated effective submarine warfare could bring Britain to her knees because of her dependence on overseas commerce. He advocated a system known as the Rudeltaktik (the so-called “wolf pack”), in which U-boats would spread out in a long line across the projected course of a convoy. Upon sighting a target, they would come together to attack en masse and overwhelm any escorting warships. While escorts chased individual submarines, the rest of the “pack” would be able to attack the merchant ships with impunity. Dönitz calculated that 300 of the latest Atlantic Boats (the Type VII) would create enough havoc among Allied shipping that Britain would be knocked out of the war.

Some historians maintain that the German U-boat strategy came close to winning the Battle of the Atlantic, that the Allies were almost defeated, and that Britain was brought to the brink of starvation. Others, including Blair and Alan Levin, disagree.

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-boat were not in convoys, but sailing alone.

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 about 10%were lost. More than 99% of all ships sailing to and from the British Isles during World War II did so successfully.

Outcomes

The Germans failed to stop the flow of strategic supplies to Britain, resulting in the build-up of troops and supplies needed for the D-Day landings. The defeat of the U-boat was a necessary precursor for accumulation of Allied troops and supplies to ensure Germany’s defeat.

Victory was achieved at a huge cost: between 1939 and 1945, 3,500 Allied merchant ships (totaling 14.5 million gross tons) and 175 Allied warships were sunk and some 72,200 Allied naval and merchant seamen lost their lives. The Germans lost 783 U-boats and approximately 30,000 sailors killed, three-quarters of Germany’s 40,000-man U-boat fleet.

Attributions

• Conflict in the Atlantic
  • “World War II.” https://en.wikipedia.org/wiki/World_War_II. Wikipedia CC BY-SA 3.0.
  • “Battle of the Atlantic.” https://en.wikipedia.org/wiki/Battle_of_the_Atlantic. Wikipedia CC BY-SA 3.0.
  • “600px-Officers_on_the_bridge.jpg.” https://en.wikipedia.org/wiki/Battle_of_the_Atlantic#/media/File:Officers_on_the_bridge.jpg. Wikipedia CC BY-SA 3.0.