The Battle of the Atlantic
British Misconceptions
Britain also had misconceptions - it was slow to recognise the U Boat threat until the war started, and gave more priority to RAF rather than Coastal Command, which had to defend British convoys.
How the British government responded to the Merchant Shipping Crisis
Britain moved to reduce imports by rationing foods, growing more foods such as vegetables from home (the Dig for Victory campaign), and simply stopping the production of certain foods (such as bananas).
Developments in 1943
By the summer of 1943, Atlantic shipping losses were reducing, with a large number of U Boats being sunk - by the end of May, 43 U Boats were sunk to 34 merchant vessels. The Atlantic now became a relatively safe sea way, allowing huge build-ups of men and supplies for Britain to proceed unharmed.
British technological gains and fallbacks
Early computers called "Bombes" were developed in Britain which were used to break German naval codes. Several enigma machines from German ships were captured, which helped the "Ultra" mission at Bletchley Park to break German codes. The breaking of these codes where a turning point in the Atlantic, as they allowed Allied Naval Command to track the positions of all U Boats, seeing which ones threatened allied shipping lines. This made the use of "hunter killer groups" much more effective, because German wolf packs locations were being constantly exposed. However, because the enigma machines were so complicated, codes had to be re-cracked as they changed regularly. This meant that there were some periods, including in 1942 when there was a "blackout", in which Ultra couldn't trace U Boats and allied shipping was still lost
German Misconceptions
Germany underestimated our technology, especially radar (the same mistake made in the Battle of Britain). In addition, the Germans knew nothing about the cracking of codes at Bletchley Park, which allowed Britain to locate U Boats and re-route endangered convoys.
Germany's main failings
Germany was stretched on two fronts from 1941, as it now was at war from the Soviet Union as well as the western allies. This meant that Germany's resources had to be stretched, and began to lack, unlike the allies resources which now increased through Lend Lease. The allies's added resources meant that they could escort a higher percentage of merchant ships across the Atlantic, as well as form "hunter killer groups", which aggressively hunted down German boats. These always kept close to the convoys just in case they came into confrontation.
Hitler's attitude to the Navy
Hitler had been sceptical about the navy prior to the war, not seeing it as important. While Dönitz, the head of the U Boat force, knew he needed 300 U boats to defeat Britain in 1940, he only had 20 operational vessels, with Hitler not devoting major priority to U Boat production until July 1940. Furthermore Germany's naval prestige has suffered as a result of the "Bismarck" sinking in 1941.
What was the Battle
This was the name of the struggle given by Churchill in 1941, for the struggle to protect merchant ships bringing supplies such as food for Britain. If U Boats were able to wipe out the merchant ships, then Britain would be starved into submission. Having rapidly increased the U Boat fleet, Germany was winning this part of the war by 1941. Churchill described his only fear in the war as "the U Boat peril".
The role of the RAF
The use of long distance aircraft gave the allies advantage over the U Boat wolf packs. The German Luftwaffe controlled the Atlantic air in the early periods of the war (which proved that without command of the air, controlling the sea was impossible). The allied solution to this was the use of the RAF as long distance aircraft, so that they could support and protect the shipping convoys much further into the Atlantic - this was something the Luftwaffe couldn't do for their ships. As the RAF now clearly threatened U boats, this resulted in the U Boats spending more time submerged underwater, making it harder to attack shipping. This meant that while the U Boats had been designed for long periods underwater to ambush convoys, this function now became merely an element of survival, in order that the RAF couldn't track the boats by radar. As more boats were forced underwater, Dönitz had real difficulty coordinating all the wolf packs as radio signals became less successful when the boats went deeper below the surface. The RAF now became dominant over the sea, and the added use of powerful searchlights on RAF planes (known as "the Leigh Light"), exposed recharging U Boats at night - they no longer had a rest bite.
Other British technical Importances
The Allies developed the use of "sonar", where U Boats could be detected below the surface of the sea. However, U Boats often released oil to cause confusion among sonar systems. While the allies also had the use of radar, this was undermined by the German use of Diesel engines underwater, as opposed to electric matter - making it hard for radar to detect the U Boats
How else did Germany counteract allied technology
The Battle of the Atlantic effectively became an "arms race" between the two sides, as the Germans were trying to counter technological advancements made by the allies through having some of their own. The greatest German advancement was the introduction of the Type 9 U Boat, capable of long range battle, which made it a greater threat to merchant ships. U Boats also became fitted with anti-radar systems. In addition, U Boat engineers used tactics which allowed the U Boat to be submerged underwater for long periods of time, and with remarkable speeds. The use of "metox" receivers allowed U Boats to avoid sudden attacks from allied escorts. Therefore, while Britain made technological gains, these were often counteracted by Germany.
The role of the USA
The USA's entry to World War Two in 1941 also proved decisive for the Atlantic campaign. The Americans brought significantly more warships to counter the U Boats, and the merchant ships could now receive more naval ship support. The number of escort vessels grew rapidly, and the use of American destroyers, along with new "flower class corvettes", allowed confrontations with U Boats to be fought off successfully. The war effort was also helped by Lend Lease
Other allied tactics
The allies decided to change their procedures for escorting convoys across the Atlantic upon realising the "U Boat peril". Seamen were now trained to take advantage when a U Boat slipped up. In addition, as well as the RAF using radar, short waved radar was added to small ships from 1941. These tactics became evident with various U boat fleets being lost at sea through confrontations by merchant escort groups. These tactics began before the German enigma machines were captured, showing that Britain didn't need to rely on technological advancement. However, once this was achieved through Ultra, the escort groups would have clear supremacy over the U Boats, this being added to by the use of the RAF. In addition, without Ultra the allies would have been more exposed when Dönitz moved the U Boats further west, as the convoys were then attacked before the battleships reached them. This was countered however when the Canadian navy agreed to escort all convoys for the full length of the Atlantic crossing.