Editing Karl Dönitz (section)

===Commander-in-chief and Grand Admiral===
[[File:Bundesarchiv Bild 183-H27590, Erich Raeder, Adolf Hitler retouched.jpg|thumb|[[Erich Raeder]] with [[Adolf Hitler]] shortly after he was replaced by Dönitz as Commander-in-chief and Grand Admiral (February 1943).]]On 30 January 1943, Dönitz replaced Erich Raeder as Commander-in-chief of the navy ({{lang|de|Oberbefehlshaber der Kriegsmarine}}) and {{lang|de|[[Großadmiral]]}} (grand admiral) of the [[Oberkommando der Marine|Naval High Command]] ({{lang|de|[[Oberkommando der Marine]]}}). In a communique to the navy he announced his intentions to retain practical control of the U-boats and his desire to fight to the end for Hitler.{{sfn|Terraine|1989|pp=520, 522}} Dönitz's inability to delegate control of the U-boat service has been construed as a weakness in the U-boat arm, contributing to the perception that Dönitz was an "impatient warrior", preoccupied with fighting battles and tactics rather than a strategist or organiser.{{sfn|Haslop|2013|p=53}}

Dönitz's promotion earned Hitler his undying loyalty. For Dönitz, Hitler had given him a "true home-coming at last, to a country in which unemployment appeared to have been abolished, the class war no longer tore the nation apart, and the shame of defeat in 1918 was being expunged."{{sfn|Terraine|1989|pp=520–522}} When war came, Dönitz became more firmly wedded to his Nazi faith. Hitler recognised his patriotism, professionalism but above all, his loyalty. Dönitz remained so, long after the war was lost. In so doing, he wilfully ignored the genocidal nature of the regime and claimed ignorance of the [[Holocaust]].{{sfn|Terraine|1989|pp=520–522}}

In the last quarter of 1942, 69 submarines had been commissioned taking the total number to 393, with 212 operational.{{sfn|Terraine|1989|p=523}} Dönitz was not satisfied and immediately began a naval construction programme which in contrast to Raeder's, laid all its emphasis on torpedo boats and submarines. Dönitz's proposed expansion ran into difficulties experienced by all of his predecessors; the lack of steel. The navy had no representation on [[Albert Speer]]'s armaments ministry, for naval production was the only sphere not under his control. Dönitz understood this worked against the navy because it lacked the elasticity to cope with breakdowns of production at any point, whereas the other services could make good production by compensating one sector at the expense of another. Without any representatives the battle of priorities was left to Speer and Göring. Dönitz had the sense to place U-boat production under Speer on the provision 40 per month were completed.{{sfn|Terraine|1989|pp=652–654}} Dönitz persuaded Hitler not to scrap the surface fleet [[capital ship]]s, though they played no role in the Atlantic during his time in command.{{sfn|Rohwer|1996|p=86}} Dönitz reasoned the destruction of the surface fleet would provide the British with a victory and heap pressure on the U-boats, for these warships were tying down British air and naval forces that would otherwise be sent into the Atlantic.{{sfn|Milner|2011|p=148}}

New construction procedures, dispensing with prototypes and the abandonment of modifications reduced construction times from 460,000-man hours to 260–300,000 to meet Speer's quota. In the spring 1944, the [[Type XXI submarine]] was scheduled to reach frontline units. In 1943 the [[Combined Bomber Offensive]] undid German plans. Dönitz and Speer were appalled by the destruction of [[Hamburg]], a major construction site.{{sfn|Terraine|1989|pp=652–654}} The battles of 1943 and 1944 were fought with the existing Type VII and [[Type IX submarine]]s. The Type VII remained the backbone of the fleet in 1943.{{sfn|Syrett|1994|p=2}}

At the end of 1942, Dönitz was faced with the appearance of [[escort carrier]]s, and long-range aircraft working with convoy escorts. To protect his boats against the latter, he ordered his boats to restrict their operations to the [[Mid-Atlantic Gap]], a stretch of ocean out of the range of land-based aircraft.{{sfn|Syrett|1994|p=15}} Allied air forces had few aircraft equipped with [[ASV Mark III radar|ASV radar]] for U-boat detection into April and May 1943, and such units would not exist in [[Newfoundland]] until June. Convoys relied on [[RAF Coastal Command]] aircraft operating from [[Northern Ireland]] and Iceland.{{sfn|Syrett|1994|p=15}} The aircraft imposed restraints on U-boat captains, who feared them for their ability to sink a submarine or alert surface warships to their position.{{sfn|Buckley|1995|pp=123–124}} In 1942 Coastal Command began forming units combined with ASV and [[Leigh Light]] to attack U-boats at night in transit to the Atlantic via the [[Bay of Biscay]], which continued into 1943. The Command was moderately successful after mid-1942.{{sfn|Buckley|1995|p=129}}
[[File:Adolf Hitler Karl Dönitz 1943. Grand Admiral Karl Doenitz (right) receives the Oak Leaves of the Knight's Cross of the Iron Cross from Third Reich leader Adolf Hitler.jpg|thumb|Grand Admiral Karl Doenitz receives the Oak Leaves of the Knight's Cross of the Iron Cross from Third Reich leader Adolf Hitler. April 1943]]
1943 began with continued tactical success for Dönitz in battle. In January [[Convoy TM 1]] was nearly destroyed. The loss of 100,000 tons of fuel in one convoy represented the most devastating loss percentage of the war—only two of nine tankers reached port. The [[Eighth Army (United Kingdom)|Eighth Army]] were forced to ration their fuel for a time, earning Dönitz the gratitude of the ''[[Afrika Korps]]''.{{sfn|Milner|2011|pp=146–147}} The [[Casablanca Conference]], held that month, identified the Atlantic as the priority. It was agreed that until the defeat of Dönitz and his men, there could be no amphibious landings in continental Europe.{{sfn|Milner|2011|p=146}} Unknown to Dönitz, Bletchley Park had broken the Shark cypher and restored the flow of Enigma information; the Admiralty was able to route convoys around wolfpacks. During January and February 1943 information was decrypted within 24 hours proving operationally useful, although this slipped at the end of the second month contributing to German interceptions.{{sfn|Milner|2011|pp=146, 155}} Even so, in appalling weather, the Germans sank only 44 ships during the month, even with 100 U-boats at sea, the majority stationed in the mid-Atlantic gap.{{sfn|Milner|2011|p=146}}

In February 1943 the strength of Allied defences were ominous for Dönitz. The battle of convoy HX 224 was ended upon the intervention of air power from Iceland. Dönitz sent 20 boats to attack SC 118 and both sides suffered heavy losses—11 merchant ships for three U-boats plus four damaged. It was "what both sides considered one of the hardest fought battles of the Atlantic war".{{sfn|Milner|2011|pp=146–147}} Despite sending 20 crews into action, Dönitz was concerned that most captains did not press home attacks. The majority of the ships sunk were by one crew, commanded by [[Siegfried von Forstner]]—he sank seven.{{sfn|Milner|2011|pp=149–150}}

In March, [[Convoy SC 121]] was attacked by 31 U-boats in two patrol lines.{{sfn|Rohwer|2015|p=75}} It was the most successful battle of the war for Dönitz.{{sfn|Milner|2011|p=156}} The battle of [[Convoys HX 229/SC 122]] was the largest convoy battle, with 40 U-boats involved.{{sfn|Roskill|1954|p=365}} Each operation was successful but all were fought in the mid-Atlantic.{{sfn|Rohwer|2015|pp=95–191}} Allied losses reached a peak in March 1943. The Admiralty later issued a report on the matter; "The Germans never came so near [to] disrupting communications between the new world and the old as in the first twenty days of March 1943."{{sfn|Price|1980|p=132}} Dönitz later conceded the March battles were to be the U-boats' last victories. New Allied techniques, tactics and technology began to turn the tide. By April 1943 U-boat morale was reaching a crisis point.{{sfn|Terraine|1989|pp=588, 593–594}} Ninety-eight new boats were sent into the Atlantic that month and although the training was thorough the crews were inexperienced and it showed. Fifteen U-boats were destroyed in March 1943 and another 15 in April.{{sfn|Terraine|1989|pp=588, 593–594}} [[Werner Hartenstein]] and [[Johann Mohr]] were notable casualties over the course of these eight weeks; the former's decision to rescue survivors of a sunken ship led to Dönitz's [[Laconia Order]], which later formed part of the criminal case against Dönitz.{{sfn|Blair|1998|pp=62, 218, 778}}

Ominous for BdU was the sudden growth of Allied air power. The Allied command accepted that air cover over the mid-Atlantic was inadequate and had drawn attention to the fact that not one VLR (Very Long Range) aircraft was to be found at any Allied air base west of Iceland. The Americans released 255 Liberators for the North Atlantic. At the end of March 1943 20 VLR aircraft were operational rising to 41 by mid-April, all of them flown by British crews. Twenty-eight anti-submarine and 11 anti-shipping squadrons were available to RAF Coastal Command, 619 aircraft in all—a striking change since September 1939.{{sfn|Roskill|1954|p=364}} The influx of radar equipped aircraft into mid-Atlantic was matched by air patrols over the Bay of Biscay. Dönitz detected a drop in morale among his captains, as did the British. Dönitz encouraged his commanders to show a "hunter's instinct" and "warrior spirit" in the face of the air–surface support group threat.{{sfn|Milner|2011|pp=157–158}}

Along with air power, the BdU was forced to contend with a large increase in Allied convoy escorts which fuelled from tankers in the convoys allowing escort across the ocean.{{sfn|Roskill|1954|p=365}} The escort carrier support groups, protected by [[destroyer]]s, which, in the words of the official naval historian of the Second World War, proved decisive; "it was the advent of the Support Groups, the Escort Carriers and the Very Long Range Aircraft which turned the tables on the U-boats-and did so with astonishing rapidity".{{sfn|Roskill|1954|pp=366–368}}

A hundred and eight ships were sunk in the first 20 days of March, and just 15 in the last 10. The official naval historian wrote, "The collapse of the enemy's offensive, when it came, was so sudden that it took him completely by surprise. We now know that, in fact, a downward trend in the U-boats' recent accomplishments could have forewarned him, but was concealed from him by the exaggerated claims made by their commanders."{{sfn|Roskill|1954|pp=367–368}} In April Dönitz lost five crews to the Coastal Command ASV Biscay offensive. Encouraged by the isolated successes of [[anti-aircraft artillery]] installed on submarines, he ordered crews to stay on the surface and fight it out with the aircraft.{{sfn|Roskill|1954|p=371}} The decision caused casualties—four boats were lost in the first week of May alone, and three more by the end.{{sfn|Milner|2011|p=179}}

For the month of April Allied losses fell to 56 ships of 327,943 tons.{{sfn|Roskill|1954|p=371}} In May 1943 the battle reached a climax with the battles of [[Convoy ONS 5]], [[Convoy SC 129]], [[Convoy SC 130]]. Throughout the battles only two ships were sunk in convoy in the Atlantic while an air anti-submarine escort was present.{{sfn|Roskill|1954|pp=373, 376}} Dönitz depended on the surface manoeuvrability of his U-boats to locate targets, assemble wolfpacks and the complicated business of positioning his forces ahead of a convoy for an attack. Allied air power determined where and when U-boats could move freely on the surface. It was the combination of convoy escorts and air power that made the Atlantic unsuitable for pack operations.{{sfn|Milner|2011|p=94}} The US Navy introduced the [[K-class blimp]]. They forced a commander to dive to prevent the aircraft marking his position or attacking.{{sfn|Milner|2011|p=96}} From 10 to 24 May 1943, ten convoys passed through the mid-Atlantic. Six of the 370 ships were sunk; three were stragglers. Thirteen U-boats were sunk; four by warships, seven by aircraft, and two shared.{{sfn|Milner|2011|pp=179–180}}

By 24 May, when Dönitz conceded defeat and withdrew the surviving crews from the field of battle, they had already lost 33 U-boats. At the end of May it had risen to 41. Dönitz tried to limit the damage to morale by declaring that the withdrawal was only temporary "to avoid unnecessary losses in a period when our weapons are shown to be at a disadvantage" and that "the battle in the north Atlantic—the decisive area—will be resumed". Dönitz did make a further attempt to regain the initiative, but the battle never reached the same pitch of intensity or hung in the balance, as during the spring of 1943. The Allied success won the Battle of the Atlantic.{{sfn|Roskill|1954|pp=377–378}} On 24 May Dönitz ordered the suspension of Atlantic operations, bringing an end to [[Black May (1943)|Black May]].{{sfn|Syrett|1994|p=145}}

Defeat in the mid-Atlantic left Dönitz in a dilemma. The U-boats had proven unable to elude convoy escorts and attack convoys with success. He was concerned about crew morale suffering from idleness and a loss of experience with the latest Allied developments in anti-submarine warfare. Aside from problems of seaworthiness among machines and crew, there were not enough [[Submarine pen]]s to store idle boats and they were a target for aircraft in port. Dönitz would not withdraw his submarines from combat operations, for he felt the ships, men and aircraft engaged in suppressing the U-boats could then be turned on Germany directly; the U-boat war was to continue.{{sfn|Syrett|1994|p=146}}