1939
118-750: 1940 1941 1942 1943 1944 1945 The early phase of the Battle of the Atlantic during which German Navy U-boats enjoyed significant success against the British Royal Navy and its Allies was referred to by U-boat crews as "the Happy Time" (" Die Glückliche Zeit "), and later the First Happy Time , after a second successful period was encountered. It started in July 1940, almost immediately after
236-614: A second front in Western Europe. Churchill declined because he felt that even with American help the British did not have adequate forces to do it, and he wished to avoid costly frontal assaults such as those that had occurred at the Somme and Passchendaele in World War I . Two tentative plans code-named Operation Roundup and Operation Sledgehammer were put forward for 1942–43, but neither
354-571: 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
472-419: A disaster within days. On 14 September 1939, Britain's most modern carrier, HMS Ark Royal , narrowly avoided being sunk when three torpedoes from U-39 exploded prematurely. U-39 was forced to surface and scuttle by the escorting destroyers, becoming the first U-boat loss of the war. Another carrier, HMS Courageous , was sunk three days later by U-29 . German success in sinking Courageous
590-982: A flotilla of 27 Italian submarines operated from the BETASOM base in Bordeaux to attack Allied shipping in the Atlantic, initially under the command of Rear Admiral Angelo Parona , then of Rear Admiral Romolo Polacchini and finally of Ship-of-the-Line Captain Enzo Grossi . The Italian submarines had been designed to operate in a different way than U-boats, and they had a number of flaws that needed to be corrected (for example huge conning towers, slow speed when surfaced, lack of modern torpedo fire control), which meant that they were ill-suited for convoy attacks, and performed better when hunting down isolated merchantmen on distant seas, taking advantage of their superior range and living standards. While initial operation met with little success (only 65343 GRT sunk between August and December 1940),
708-589: A front line from Caumont-l'Éventé to the south-east of Caen in order to protect the American flank, while establishing airfields near Caen. Possession of Caen and its surroundings would give the Anglo-Canadian forces a suitable staging area for a push south to capture the town of Falaise . A secure lodgement would be established and an attempt made to hold all territory captured north of the Avranches -Falaise line during
826-473: A naval convoy approaching Cap d'Antifer (about 80 km from the actual D-Day landings). The illusion was bolstered by a group of small vessels towing barrage balloons . No. 218 Squadron RAF also dropped "window" near Boulogne-sur-Mer in Operation Glimmer . On the same night, a small group of Special Air Service (SAS) operators deployed dummy paratroopers over Le Havre and Isigny. These dummies led
944-550: A necessary element of the plan for the landings. Information on the exact date and location of the landings was provided only to the topmost levels of the armed forces. Men were sealed into their marshalling areas at the end of May, with no further communication with the outside world. Troops were briefed using maps that were correct in every detail except for the place names, and most were not told their actual destination until they were already at sea. A news blackout in Britain increased
1062-462: 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. Neither aircraft nor early forms of Sonar , (called ASDIC by the British), were considered a serious threat at the time. ASDIC could not detect a surfaced submarine and its range was less than that of an electric torpedo , aircraft could not operate at night and, during
1180-434: A raider hunting for independently sailing ships, and to avoid combat with superior forces. 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
1298-466: A relatively narrow isthmus , so these sites were rejected. The Pas de Calais, the closest point in continental Europe to Britain, was the location of launch sites for V-1 and V-2 rockets , then still under development. The Germans regarded it as the most likely initial landing zone and accordingly made it the most heavily fortified region; however, it offered the Allies few opportunities for expansion as
SECTION 10
#17328481619701416-502: A second attack would take place at Calais. Military and civilian personnel alike were aware of the need for secrecy, and the invasion troops were as much as possible kept isolated, especially in the period immediately before the invasion. American general Henry J. F. Miller was sent back to the United States in disgrace after revealing the invasion date at a party. The Germans thought they had an extensive network of spies operating in
1534-416: 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
1652-567: Is a matter of interpretation, with some sources claiming October 1940 and others extending it to April 1941, after the Germans lost three prominent U-boat commanders: Günther Prien , Joachim Schepke and Otto Kretschmer . This German World War II article is a stub . You can help Misplaced Pages by expanding it . Battle of the Atlantic 1939 1940 1941 1942 1943 1944 1945 Asia-Pacific Mediterranean and Middle East Other campaigns Coups The Battle of
1770-606: The 12th SS Panzer Division Hitlerjugend , were, for the most part, younger and far better equipped and trained than the static troops stationed along the coast. In early 1944, OB West was significantly weakened by personnel and materiel transfers to the Eastern Front. During the Soviet Dnieper–Carpathian Offensive (24 December 1943 – 17 April 1944), the German High Command was forced to transfer
1888-683: The 21st Army Group , which comprised all the land forces involved in the operation. The Normandy coast in northwestern France was chosen as the site of the landings, with the Americans assigned to land at sectors codenamed Utah and Omaha , the British at Sword and Gold , and the Canadians at Juno . To meet the conditions expected on the Normandy beachhead, special technology was developed, including two artificial ports called Mulberry harbours and an array of specialised tanks nicknamed Hobart's Funnies . In
2006-526: The Armoured Ramp Carrier , which other tanks could use as a bridge to scale sea-walls or to overcome other obstacles. In some areas, the beaches consisted of a soft clay that could not support the weight of tanks. The Bobbin tank unrolled matting over the soft surface, leaving it behind as a route for ordinary tanks. The Assault Vehicle Royal Engineers (AVRE) was a Churchill tank modified for many combat engineering tasks, including laying bridges; it
2124-747: The BBC produced over ten million items, some of which proved useful. The French resistance provided details on Axis troop movements and on construction techniques used by the Germans for bunkers and other defensive installations. Many German radio messages were encoded using the Enigma machine and other enciphering techniques and the codes were changed frequently. A team of code breakers stationed at Bletchley Park worked to break codes as quickly as possible to provide advance information on German plans and troop movements. British military intelligence code-named this information Ultra intelligence as it could only be provided to
2242-702: The British Expeditionary Force ) in the Dunkirk evacuation (27 May to 4 June). British planners reported to Prime Minister Winston Churchill on 4 October that even with the help of other Commonwealth countries and the United States, it would not be possible to regain a foothold in continental Europe in the near future. After the Axis invaded the Soviet Union in June 1941, Soviet leader Joseph Stalin began pressing for
2360-529: The Eastern Front , meant the Germans no longer had a pool of able young men from which to draw. German soldiers were now on average six years older than their Allied counterparts. Many in the Normandy area were Ostlegionen (eastern legions)—conscripts and "volunteers" from Turkestan , Russia, Mongolia, and elsewhere. The Wehrmacht had provided them mainly with unreliable captured equipment; they lacked motorised transport. Formations that arrived later, such as
2478-663: The English Channel on 6 June, and more than two million Allied troops were in France by the end of August. The decision to undertake cross-channel landings in 1944 was made at the Trident Conference in Washington in May 1943. General Dwight D. Eisenhower was appointed commander of Supreme Headquarters Allied Expeditionary Force , and General Bernard Montgomery was named commander of
SECTION 20
#17328481619702596-700: The Fall of France , which brought the German U-boat fleet closer to the British shipping lanes in the Atlantic. From July 1940 to the end of October, 282 Allied ships were sunk off the north-west approaches to Ireland for a loss of 1,489,795 tons of merchant shipping. The reason for this successful Axis period was the British lack of radar and huff-duff -equipped ships which meant that the U-boats were very hard to detect when they made nighttime surface attacks – ASDIC ( sonar ) could only detect submerged U-boats. When it ended
2714-764: 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 and place ship crews in "a place of safety" (for which lifeboats did not qualify, except under particular circumstances) before sinking them, unless the ship in question showed "persistent refusal to stop...or active resistance to visit or search". These regulations did not prohibit arming merchantmen, but doing so, or having them report contact with submarines (or raiders ), made them de facto naval auxiliaries and removed
2832-519: The Liberation of Paris followed on 25 August. German forces retreated east across the Seine on 30 August 1944, marking the close of Operation Overlord. In June 1940, Germany's leader Adolf Hitler had triumphed in what he called "the most famous victory in history"—the fall of France . British craft evacuated to England over 338,000 Allied troops trapped along the northern coast of France (including much of
2950-624: The Supermarine Spitfire and Hawker Typhoon greatly limited the number of potential landing-sites, as comprehensive air support depended upon having planes overhead for as long as possible. Morgan considered four sites for the landings: Brittany , the Cotentin Peninsula , Normandy, and the Pas de Calais . As Brittany and Cotentin are peninsulas, the Germans could have cut off the Allied advance at
3068-470: The Transport Plan , communications infrastructure and road and rail links were bombed to cut off the north of France and to make it more difficult to bring up reinforcements. These attacks were widespread so as to avoid revealing the exact location of the invasion. Elaborate deceptions were planned to prevent the Germans from determining the timing and location of the invasion. The coastline of Normandy
3186-603: The Trident Conference in Washington in May 1943 took the decision to launch a cross-Channel invasion within the next year. Churchill favoured making the main Allied thrust into Germany from the Mediterranean theatre , but the Americans, who were providing the bulk of the men and equipment, over-ruled him. British Lieutenant-General Frederick E. Morgan was appointed Chief of Staff, Supreme Allied Commander (COSSAC), to begin detailed planning. The initial plans were constrained by
3304-773: 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
3422-430: The highest tides . The Allies wanted to schedule the landings for shortly before dawn, midway between low and high tide, with the tide coming in. This would improve the visibility of obstacles the enemy had placed on the beach while minimising the amount of time the men had to spend exposed in the open. Specific criteria were also set for wind speed, visibility, and cloud cover. Eisenhower had tentatively selected 5 June as
3540-426: The metric bands , lacked target discrimination and range. Moreover, corvettes were too slow to catch a surfaced U-boat. Pack tactics were first used successfully in September and October 1940 to devastating effect, in a series of convoy battles. On September 21, convoy HX 72 of 42 merchantmen was attacked by a pack of four U-boats, which sank eleven ships and damaged two over the course of two nights. In October,
3658-571: The Allied convoys singly, U-boats were directed to work in wolf packs ( Rudel ) coordinated by radio. The boats spread out into a long patrol line that bisected the path of the Allied convoy routes. Once in position, the crew studied the horizon through binoculars looking for masts or smoke, or used hydrophones to pick up propeller noises. When one boat sighted a convoy, it would report the sighting to U-boat headquarters , shadowing and continuing to report as needed until other boats arrived, typically at night. Instead of being faced by single submarines,
First Happy Time - Misplaced Pages Continue
3776-524: The Atlantic , the longest continuous military campaign 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. The Battle of
3894-761: 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
4012-462: The Atlantic were Carlo Fecia di Cossato , commander of the submarine Enrico Tazzoli , and Gianfranco Gazzana-Priaroggia , commander of Archimede and then of Leonardo da Vinci . Despite their success, U-boats were still not recognised as the foremost threat to the North Atlantic convoys. With the exception of men like Dönitz, most naval officers on both sides regarded surface warships as
4130-514: The Atlantic", which he compared to the Battle of France , fought the previous summer. The first meeting of the Cabinet's "Battle of the Atlantic Committee" was on March 19. Churchill claimed to have coined the phrase "Battle of the Atlantic" shortly before Alexander's speech, but there are several examples of earlier usage. Following the use of unrestricted submarine warfare by Germany in
4248-454: The Atlantic, the British were forced to provide battleship escorts to as many convoys as possible. This twice saved convoys from slaughter by the German battleships. In February, the old battleship HMS Ramillies deterred an attack on HX 106 . A month later, SL 67 was saved by the presence of HMS Malaya . Operation Overlord 16,714 Allied airmen killed (8,536 members of
4366-454: The Atlantic. The power of a raider against a convoy was demonstrated by the fate of convoy HX 84 , attacked by the pocket battleship Admiral Scheer on 5 November 1940. Admiral Scheer quickly sank five ships and damaged several others as the convoy scattered. Only the sacrifice of the escorting armed merchant cruiser HMS Jervis Bay (whose commander, Edward Fegen , was awarded a posthumous Victoria Cross ) and failing light allowed
4484-646: The Battle of the Atlantic from 1941 onwards. These were primarily Fw 200 Condors. The Condors also bombed convoys that were beyond land-based fighter cover and thus defenceless. Initially, the Condors were very successful, claiming 365,000 tons of shipping in early 1941. These aircraft were few in number, however, and directly under Luftwaffe control; in addition, the pilots had little specialised training for anti-shipping warfare, limiting their effectiveness. The Germans received help from their allies. From August 1940,
4602-405: 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
4720-486: The British Naval Cypher No. 3, allowing the Germans to estimate where and when convoys could be expected. In response, the British applied the techniques of operations research to the problem and came up with some counter-intuitive solutions for protecting convoys. They realised that the area of a convoy increased by the square of its perimeter, meaning the same number of ships, using the same number of escorts,
4838-399: The British admiralty failed to appreciate the limitations of ASDIC: range was limited, ASDIC worked only well if the speed of the operating vessel was below eight knots, ASDIC was hampered by rough weather and it took a very skilled operator to distinguish echoes from thermoclines , whales, shoals of fish and wrecks. Also, early versions could not look directly down, so contact was lost during
First Happy Time - Misplaced Pages Continue
4956-509: 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
5074-661: The British side, Lieutenant-General Miles Dempsey commanded the Second Army , under which XXX Corps was assigned to Gold and I Corps to Juno and Sword. Land forces were under the command of Montgomery, and air command was assigned to Air Chief Marshal Sir Trafford Leigh-Mallory . The First Canadian Army included personnel and units from Poland , Belgium, and the Netherlands. Other Allied nations participated. The Allied Expeditionary Air Force flew over 3,200 photo-reconnaissance sorties from April 1944 until 6 June. Photos of
5192-468: 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) to strangle the British economy. 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 :
5310-660: The Channel and along the east coast in defence of shipping lanes, and also offensive mine barrages on the German U-boat lanes toward the Atlantic Ocean. In 1939, the Kriegsmarine lacked the strength to challenge the combined British Royal Navy and French Navy ( Marine Nationale ) 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
5428-692: The Combined Training Centre in Inveraray in Scotland. Naval exercises took place in Northern Ireland, and medical teams in London and elsewhere rehearsed how they would handle the expected waves of casualties. Paratroopers conducted exercises, including a huge demonstration drop on 23 March 1944 observed by Churchill, Eisenhower, and other top officials. Allied planners considered tactical surprise to be
5546-457: The German U-boat torpedoes : both the impact pistol and the magnetic influence pistol (detonation mechanism) were defective, and the torpedoes did not run at the proper depth, often undershooting targets. Only one British warship was sunk by U-boats in more than 38 attacks. As the news spread through the U-boat fleet, it began to undermine morale . Since the effectiviness of the magnetic pistol
5664-472: The German tactics against the inadequate British anti-submarine methods. On 1 December, seven German and three Italian submarines caught HX 90 , sinking 10 ships and damaging three others. At the end of the year 1940, the Admiralty viewed the number of ships sunk with growing alarm. Damaged ships might survive but could be out of commission for long periods. Two million gross tons of merchant shipping—13% of
5782-563: The German war effort: Germany spent more money on producing naval vessels than it did every type of ground vehicle combined, including tanks. The Battle of the Atlantic has been called the "longest, largest, and most complex" naval battle in history. 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
5900-910: The Germans to believe an additional airborne assault had occurred. Training exercises for the Overlord landings took place as early as July 1943. As the nearby beach resembled the planned Normandy landing-site, the town of Slapton in Devon , was evacuated in December 1943, and taken over by the armed forces as a site for training exercises that included the use of landing craft and the management of beach obstacles. A friendly fire incident there on 27 April 1944 resulted in as many as 450 deaths. The following day, an additional estimated 749 American soldiers and sailors died when German torpedo-boats surprised members of Assault Force "U" conducting Exercise Tiger . Exercises with landing craft and live ammunition also took place at
6018-478: The Italian intervention was not favourably regarded by Dönitz, who characterised Italians as "inadequately disciplined" and "unable to remain calm in the face of the enemy". They were unable to co-operate in wolf pack tactics or even reliably report contacts or weather conditions, and their area of operation was moved away from those of the Germans. Amongst the more successful Italian submarine commanders who operated in
SECTION 50
#17328481619706136-573: The Low Countries, with another 18 stationed in Denmark and Norway. Fifteen divisions were in the process of formation in Germany, but there was no strategic reserve. The Calais region was defended by the 15th Army under Generaloberst (Colonel General) Hans von Salmuth , and Normandy by the 7th Army commanded by Generaloberst Friedrich Dollmann . Combat losses throughout the war, particularly on
6254-504: 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 '." 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
6372-443: The U-boats were guaranteed to be found, the convoys. Each convoy consisted of between 30 and 70 mostly unarmed merchant ships. Some British naval officials, particularly the First Lord of the Admiralty, Winston Churchill , sought a more 'offensive' strategy. The Royal Navy formed anti-submarine hunting groups based on aircraft carriers to patrol the shipping lanes in the Western Approaches and hunt for German U-boats. This strategy
6490-412: 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. 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
6608-408: The UK, but in fact, all their agents had been captured, and some had become double agents working for the Allies as part of the Double-Cross System . The double agent Juan Pujol García , a Spanish opponent of the Nazis known by the code name "Garbo", developed over the two years leading up to D-Day a fake network of informants that the Germans believed were collecting intelligence on their behalf. In
6726-528: The USAAF, and 8,178 flying under the command of the RAF) Civilian deaths: Airborne assault British Sector American Sector Normandy landings American Sector Anglo-Canadian Sector Logistics Ground campaign American Sector Anglo-Canadian Sector Breakout Air and Sea operations Supporting operations Aftermath Luxembourg The Netherlands Belgium France Britain 1941–1943 1944–1945 Germany Strategic campaigns Operation Overlord
6844-404: The United States beginning September 13, 1941. 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,
6962-445: The area is bounded by numerous rivers and canals. On the other hand, landings on a broad front in Normandy would permit simultaneous threats against the port of Cherbourg , coastal ports further west in Brittany, and an overland attack towards Paris and eventually into Germany. The Allies therefore chose Normandy as the landing site. The most serious drawback of the Normandy coast – the lack of port facilities – would be overcome through
7080-419: The area to bolster the illusion that a large force was gathering there. As well as the broadcast of fake radio-traffic, genuine radio messages from 21st Army Group were first routed to Kent via landline and then broadcast, to give the Germans the impression that most of the Allied troops were stationed there. Patton remained stationed in England until 6 July, thus continuing to deceive the Germans into believing
7198-511: The boats needed to return to harbour to refuel, re-arm, re-stock supplies, and refit. The harsh winter of 1939–40, which froze over many of the Baltic ports, seriously hampered the German offensive by trapping several new U-boats in the ice. Hitler's plans to invade Norway and Denmark in the spring of 1940 led to the withdrawal of the fleet's surface warships and most of the ocean-going U-boats for fleet operations in Operation Weserübung . The resulting Norwegian campaign revealed serious flaws in
SECTION 60
#17328481619707316-638: 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
7434-402: The capture of the port at Cherbourg. This significant expansion required the acquisition of additional landing craft, which caused the invasion to be delayed by a month until June 1944. Eventually the Allies committed 39 divisions to the Battle of Normandy: 22 American, 12 British, three Canadian, one Polish, and one French, totalling over a million troops. "Overlord" was the name assigned to
7552-574: The coastline were taken at extremely low altitude to show the invaders the terrain, obstacles on the beach, and defensive structures such as bunkers and gun emplacements. To conceal the location of the invasion, sorties were flown along all European coastline. Inland terrain, bridges, troop emplacements, and buildings were also photographed, in many cases from several angles. Members of Combined Operations Pilotage Parties clandestinely prepared detailed harbour maps, including depth soundings . An appeal for holiday pictures and postcards of Europe announced on
7670-633: The conditions would be unfavourable for Allied aircraft. After much discussion, Eisenhower decided that the invasion should go ahead. Allied control of the Atlantic meant that German meteorologists did not have access to as much information as the Allies on incoming weather patterns. As the Luftwaffe meteorological centre in Paris predicted two weeks of stormy weather, many Wehrmacht commanders left their posts to attend war games in Rennes , and men in many units were given leave. Marshal Erwin Rommel returned to Germany for his wife's birthday and to meet Hitler to try to get more tanks. Had Eisenhower postponed
7788-487: The convoy escorts then had to cope with groups of up to half a dozen U-boats attacking simultaneously. The most daring commanders, such as Kretschmer, penetrated the escort screen and attacked from within the columns of merchantmen. The escort vessels, which were too few in number and often lacking in endurance, had no answer to multiple submarines attacking on the surface at night, as their ASDIC worked well only against underwater targets. Early British marine radar, working in
7906-421: The date for the assault; however, on 4 June, conditions were clearly unsuitable for a landing, as high winds and heavy seas made it impossible to launch landing craft, and low clouds would prevent aircraft from finding their targets. By the evening of 4 June, the Allied meteorological team, headed by Group Captain James Stagg of the Royal Air Force , predicted that the weather would improve sufficiently so that
8024-443: The day, an alert U-boat could dive before the aircraft attacked. Dönitz could not convince Raeder of his ideas, so 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. With
8142-420: The development and deployment of artificial harbours. The COSSAC staff planned to begin the invasion on 1 May 1944. The initial draft of the plan was accepted at the Quebec Conference in August 1943. General Dwight D. Eisenhower was appointed commander of Supreme Headquarters Allied Expeditionary Force (SHAEF). General Bernard Montgomery was named commander of the 21st Army Group , which comprised all of
8260-406: The east since the creation of Führer Directive 51 , which no longer allowed any transfers from the west to the east. There were also transfers to the Italian front: von Rundstedt complained that many of his best units had been sent on a "fool's errand" to Italy, saying it was "madness ... that frightful boot of a country should have been evacuated ... we should have held a decent front with
8378-399: The eastern flank to secure the Orne River bridges, and north of Carentan on the western flank. The initial goal was to capture Carentan, Isigny , Bayeux , and Caen. The Americans, assigned to land at Utah and Omaha, were to cut off the Cotentin Peninsula and capture the port facilities at Cherbourg. The British at Sword and Gold , and the Canadians at Juno , were to capture Caen and form
8496-459: The effectiveness of the deception operations. Travel to and from the Republic of Ireland was banned, and movement within several kilometres of the coast of England restricted. The invasion planners specified a set of conditions regarding the timing of the invasion, deeming only a few days in each month suitable. A full moon was desirable, as it would provide illumination for aircraft pilots and have
8614-423: The entire II SS Panzer Corps from France, consisting of the 9th and 10th SS Panzer Divisions, as well as the 349th Infantry Division , 507th Heavy Panzer Battalion and the 311th and 322nd StuG Assault Gun Brigades. All told, the German forces stationed in France were deprived of 45,827 troops and 363 tanks, assault guns, and self-propelled anti-tank guns. It was the first major transfer of forces from France to
8732-497: The establishment of a large-scale lodgement on the Continent. The first phase, the amphibious invasion and establishment of a secure foothold, was code-named Operation Neptune and is often referred to as "D-Day". To gain the required air superiority needed to ensure a successful invasion, the Allies launched a strategic bombing campaign (codenamed Pointblank ) to target German aircraft-production, fuel supplies, and airfields. Under
8850-470: The expectation that fuel would be difficult or impossible to obtain on the continent, the Allies built a "Pipe-Line Under The Ocean" ( PLUTO ). Specially developed pipes 3 in (76 mm) in diameter were to be laid under the Channel from the Isle of Wight to Cherbourg by D-Day plus 18. Technical problems and the delay in capturing Cherbourg meant the pipeline was not operational until 22 September. A second line
8968-443: The final stages of a depth charge attack. The basic set could detect range and bearing, but target depth could only be estimated from the range at which contact was lost. An escort swept its ASDIC beam in an arc from one side of its course to the other, stopping the transducer every few degrees to send out a signal. On detection of a submarine, the escort would close in at moderate speed and increase its speed to attack. The intention
9086-582: The first day, but gained a tenuous foothold that they gradually expanded when they captured the port at Cherbourg on 26 June and the city of Caen on 21 July. A failed counterattack by German forces in response to Allied advances on 7 August left 50,000 soldiers of the German 7th Army trapped in the Falaise pocket by 19 August. The Allies launched a second invasion from the Mediterranean Sea of southern France (code-named Operation Dragoon ) on 15 August, and
9204-521: The first three months of war. The British and French formed a series of hunting groups including three battlecruisers , three aircraft carriers, and 15 cruisers to seek the raider and her sister Deutschland , which was operating in the North Atlantic. These hunting groups had no success until Admiral Graf Spee was caught off the mouth of the River Plate between Argentina and Uruguay by an inferior British force. After suffering damage in
9322-747: The first three weeks. The Allied armies would then swing left to advance towards the River Seine . The invasion fleet, led by Admiral Sir Bertram Ramsay , was split into the Western Naval Task Force (under Admiral Alan Kirk ) supporting the American sectors and the Eastern Naval Task Force (under Admiral Sir Philip Vian ) in the British and Canadian sectors. The American forces of the First Army , led by Lieutenant General Omar Bradley , comprised VII Corps (Utah) and V Corps (Omaha). On
9440-615: The fleet available to the British—were under repair and unavailable, which had the same effect in slowing down cross-Atlantic supplies. Nor were the U-boats the only threat. Following some early experience in support of the war at sea during Operation Weserübung, the Luftwaffe began to take a toll of merchant ships. Martin Harlinghausen and his recently established command— Fliegerführer Atlantik —contributed small numbers of aircraft to
9558-554: The introduction of ASDIC, the British Admiralty believed to have effectively neutralized the submarine threat. Hence the number of destroyers and convoy escorts was reduced and the anti-submarine branch was seen as third rate. Although destroyers were also equipped with ASDIC, it was expected that these ships would be used in fleet actions rather than anti-submarine warfare, so they were not extensively trained in their use. Trials with ASDIC were usually conducted in ideal conditions and
9676-405: The invasion again, the next available period with the right combination of tides (but without the desirable full moon) was two weeks later, from 18 to 20 June. As it happened, during this period the invaders would have encountered a major storm lasting four days, between 19 and 22 June, that would have made the initial landings impossible. Nazi Germany had at its disposal 50 divisions in France and
9794-470: The invasion could go ahead on 6 June. He met Eisenhower and other senior commanders at their headquarters at Southwick House in Hampshire to discuss the situation. General Montgomery and Major-General Walter Bedell Smith , Eisenhower's chief of staff, were eager to launch the invasion. Admiral Bertram Ramsay was prepared to commit his ships, while Air Chief Marshal Trafford Leigh-Mallory expressed concern that
9912-412: The invasion, the Allies conducted Operation Bodyguard , the overall strategy designed to mislead the Germans as to the date and location of the main Allied landings. Operation Fortitude included Fortitude North, a misinformation campaign using fake radio-traffic to lead the Germans into expecting an attack on Norway, and Fortitude South, a major deception designed to fool the Germans into believing that
10030-469: The land forces involved in the invasion. On 31 December 1943, Eisenhower and Montgomery first saw the COSSAC plan, which proposed amphibious landings by three divisions , with two more divisions in support. The two generals immediately insisted on expanding the scale of the initial invasion to five divisions, with airborne descents by three additional divisions, to allow operations on a wider front and to speed up
10148-447: The landings would take place at Pas de Calais in July. A fictitious First U.S. Army Group was invented, supposedly located in Kent and Sussex under the command of Lieutenant General George S. Patton . The Allies constructed dummy tanks, trucks, and landing craft, and positioned them near the coast. Several military units, including II Canadian Corps and 2nd Canadian Division , moved into
10266-524: The months leading up to the landings, the Allies conducted Operation Bodyguard , a substantial military deception that used electronic and visual misinformation to mislead the Germans as to the date and location of the main Allied landings. Adolf Hitler placed Field Marshal Erwin Rommel in charge of developing fortifications all along Hitler's proclaimed Atlantic Wall in anticipation of landings in France. The Allies failed to accomplish their objectives for
10384-726: The months preceding D-Day, Pujol sent hundreds of messages to his superiors in Madrid, messages specially prepared by the British intelligence service to convince the Germans that the attack would come in July at Calais. Many of the German radar stations on the French coast were destroyed by the RAF in preparation for the landings. On the night before the invasion, in Operation Taxable , 617 Squadron (the famous "Dambusters") dropped strips of "window", metal foil that German radar operators interpreted as
10502-563: The most senior commanders. The Enigma code used by Field Marshal Gerd von Rundstedt , Oberbefehlshaber West (Supreme Commander West; OB West ), commander of the Western Front , was broken by the end of March. German intelligence changed the Enigma codes after the Allied landings but by 17 June the Allies were again consistently able to read them. After the disastrous Dieppe Raid , the Allies developed new technologies for Overlord. To supplement
10620-685: The number of landing craft , most of which were already committed in the Mediterranean and in the Pacific. In part because of lessons learned in the Dieppe Raid of 19 August 1942, the Allies decided not to directly assault a heavily defended French seaport in their first landing. The failure at Dieppe also highlighted the need for adequate artillery and air support, particularly close air support , and specialised ships able to travel extremely close to shore. The short operating range of British aircraft such as
10738-489: The number of U-boats on patrol in the Atlantic began to increase, the number of escorts available for the convoys was greatly reduced. 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
10856-582: The other merchantmen to escape. The British now suspended North Atlantic convoys, and the Home Fleet put to sea to try to intercept Admiral Scheer . The search failed and Admiral Scheer disappeared into the South Atlantic. She reappeared in the Indian Ocean the following month. Other German surface raiders now began to make their presence felt. On Christmas Day 1940, the cruiser Admiral Hipper attacked
10974-609: The other navies of the world combined. Similarly the role of aircraft had been neglected; the Royal Air Force had organised a Coastal Command to support the Royal Navy, but it possessed insufficient aircraft, had no long range aircraft nor were aircraft crew trained in anti-submarine warfare. The only weapon against submarines was inadequate bombs. Finally, it was not forgotten that in World War I, mines had sunk more U-boats than any other weapon. Plans were drafted for mine fields in
11092-587: The preliminary offshore bombardment and aerial assaults, some of the landing craft were equipped with artillery and anti-tank guns to provide close supporting fire. The Allies had decided not to immediately attack any of the heavily protected French ports and two artificial ports, called Mulberry harbours , were designed by COSSAC planners. Each assembly consisted of a floating outer breakwater , inner concrete caissons (called Phoenix breakwaters ) and several floating piers. The Mulberry harbours were supplemented by blockship shelters (codenamed "Gooseberries"). With
11210-521: The protection of the cruiser rules. 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
11328-515: 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
11446-495: The situation improved gradually over time, and up to August 1943 the 32 Italian submarines that operated there sank 109 ships of 593,864 tons, for 17 subs lost in return, giving them a subs-lost-to-tonnage sunk ratio similar to Germany's in the same period, and higher overall. The Italians were also successful with their use of " human torpedo " chariots, disabling several British ships in Gibraltar. Despite these successes,
11564-419: The slow convoy SC 7 , with an escort of two sloops and two corvettes, was overwhelmed, losing 59% of its ships. The battle for HX 79 in the following days was in many ways worse for the escorts than for SC 7. The loss of a quarter of the convoy without any loss to the U-boats, despite a very strong escort (two destroyers, four corvettes, three trawlers, and a minesweeper) demonstrated the effectiveness of
11682-429: The subsequent action, she took shelter in neutral Montevideo harbour and was scuttled on 17 December 1939. After this initial burst of activity, the Atlantic campaign quietened down. Admiral Karl Dönitz , commander of the U-boat fleet, had planned a maximum submarine effort for the first month of the war, with almost all the available U-boats out on patrol in September. That level of deployment could not be sustained;
11800-541: The threat of war became more clear it was realised that Britain could not rely on the London Naval Treaty that outlawed unrestricted submarine warfare. The organisational infrastructure for convoys had been maintained since World War I, with a thorough and systematic upgrade in the second half of the 1930s, but not enough escorts were available for convoy escorting, and a crash program for building Tree-class trawlers , Flower-class corvettes and Hunt-class destroyers
11918-475: The troop convoy WS 5A, but was driven off by the escorting cruisers. Admiral Hipper had more success two months later, on 12 February 1941, when she found the unescorted convoy SLS 64 of 19 ships and sank seven of them. In January 1941, the battleships Scharnhorst and Gneisenau put to sea from Germany to raid the shipping lanes in Operation Berlin . With so many German raiders at large in
12036-516: The ultimate commerce destroyers. For the first half of 1940, there were no German surface raiders in the Atlantic because the German Fleet had been concentrated for the invasion of Norway. The sole pocket battleship raider, Admiral Graf Spee , had been stopped at the Battle of the River Plate by an inferior and outgunned British squadron. From the summer of 1940 a small but steady stream of warships and armed merchant raiders set sail from Germany for
12154-434: Was a converted civilian airliner—a stop-gap solution for Fliegerführer Atlantik . Due to ongoing friction between the Luftwaffe and Kriegsmarine , the primary source of convoy sightings was the U-boats themselves. Since a submarine's bridge was very close to the water, their range of visual detection was quite limited. The best source proved to be the codebreakers of B-Dienst who had succeeded in deciphering
12272-528: Was already reduced by the degaussing of Allied ships, Dönitz decided to use new contact pistols, which were copied from British torpedoes found in the captured British submarine HMS Seal . The depth setting mechanism was improved but only in January 1942 were the last complications with that mechanism discovered and fixed, making the torpedo a more reliable weapon. The German occupation of Norway in April 1940,
12390-408: Was armed with a demolition gun that could fire large charges into pillboxes . The Duplex-Drive tank ( DD tank ), another design developed by Hobart's group, was a self-propelled amphibious tank kept afloat using a waterproof canvas screen inflated with compressed air. These tanks were easily swamped, and on D-Day, many sank before reaching the shore, especially at Omaha. In the months leading up to
12508-443: Was better protected in one convoy than in two. A large convoy was as difficult to locate as a small one. Moreover, reduced frequency also reduced the chances of detection, as fewer large convoys could carry the same amount of cargo, while large convoys take longer to assemble. Therefore, a few large convoys with apparently few escorts were safer than many small convoys with a higher ratio of escorts to merchantmen. Instead of attacking
12626-468: Was declared in September 1939, including most of the available U-boats and the "pocket battleships" Deutschland and Admiral Graf Spee which had 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
12744-570: Was deemed by the British to be practical or likely to succeed. Instead, the Allies expanded their activity in the Mediterranean, launching the Operation Torch an invasion of French North Africa in November 1942, the Allied invasion of Sicily in July 1943, and Allied invasion of Italy in September. These campaigns provided the troops with valuable experience in amphibious warfare . Those attending
12862-435: Was deeply flawed because a U-boat, with its tiny silhouette, was always likely to spot the surface warships and submerge long before it was sighted. The carrier aircraft were little help; although they could spot submarines on the surface, at this stage of the war they had no adequate weapons to attack them, and any submarine found by an aircraft was long gone by the time surface warships arrived. The hunting group strategy proved
12980-506: Was divided into seventeen sectors, with code-names using a spelling alphabet —from Able, west of Omaha , to Roger on the east flank of Sword . Eight further sectors were added when the invasion was extended to include Utah on the Cotentin Peninsula. Sectors were further subdivided into beaches identified by the colours Green, Red, and White. Allied planners envisaged preceding the sea-borne landings with airborne drops: near Caen on
13098-463: Was initiated. Merchant ships that were either too fast or too slow for convoys, were to be equipped with a self-defence gun against surfaced submarine attacks, thus forcing an attacking U-boat to spend its precious torpedoes. This, however, removed these ships from the protection of the cruiser rules under the prize law . Nevertheless, despite this lack of readiness, in 1939 the Royal Navy probably had as many ASDIC equipped warships in service as all
13216-549: Was laid from Dungeness to Boulogne in late October. The British built specialised tanks, nicknamed Hobart's Funnies , to deal with conditions expected during the Normandy campaign. Developed under the supervision of Major-General Percy Hobart , these were modified M4 Sherman and Churchill tanks . Examples include the Sherman Crab tank (equipped with a mine flail), the Churchill Crocodile (a flame-throwing tank), and
13334-452: Was referred to by U-boat crews as "the Happy Time" (" Die Glückliche Zeit "). Churchill would later write: "...the only thing that ever frightened me during the war was the U-boat peril". The biggest challenge for the U-boats was to find the convoys in the vastness of the ocean. The Germans had a handful of very long-range Focke-Wulf Fw 200 Condor aircraft based at Bordeaux and Stavanger , which were used for reconnaissance. The Condor
13452-470: Was surpassed a month later when Günther Prien in U-47 penetrated the British base at Scapa Flow and sank the old battleship HMS Royal Oak at anchor, immediately becoming a hero in Germany. In the South Atlantic, British forces were stretched by the cruise of Admiral Graf Spee , which sank nine merchant ships of 50,000 gross register tons (GRT) in the South Atlantic and Indian Ocean during
13570-451: Was the codename for the Battle of Normandy , the Allied operation that launched the successful liberation of German-occupied Western Europe during World War II . The operation was launched on 6 June 1944 ( D-Day ) with the Normandy landings (Operation Neptune). A 1,200-plane airborne assault preceded an amphibious assault involving more than 5,000 vessels. Nearly 160,000 troops crossed
13688-498: Was to be many months before these ships contributed to the campaign. The early U-boat operations from the French bases were spectacularly successful. This was the heyday of the great U-boat aces like Günther Prien of U-47 , Otto Kretschmer ( U-99 ), Joachim Schepke ( U-100 ), Engelbert Endrass ( U-46 ), Victor Oehrn ( U-37 ) and Heinrich Bleichrodt ( U-48 ). U-boat crews became heroes in Germany. From June until October 1940, over 270 Allied ships were sunk; this period
13806-403: Was to dominate 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 minelaying and operations in British coastal waters. Much of the early German anti-shipping activity involved minelaying by destroyers , aircraft and U-boats off British ports. With the outbreak of war,
13924-416: Was to pass over the submarine, rolling depth charges from chutes at the stern, while throwers fired further charges to either side, laying a pattern of depth charges. To effectively disable a submarine, a depth charge had to explode within about 20 ft (6.1 m). Since early ASDIC equipment was poor at determining depth, it was usual to vary the depth settings on part of the pattern. When in spring 1939
#969030