On 7 May 1945, he ordered Alfred Jodl, Chief of Operations Staff of the Oberkommando der Wehrmacht (OKW), to sign the German instruments of surrender in Reims, France, formally ending the War in Europe.

[8] In August 1914, the Breslau and the battlecruiser SMS Goeben were sold to the Ottoman Navy; the ships were renamed the Midilli and the Yavuz Sultan Selim, respectively.

[20] Dönitz revived Hermann Bauer's idea of grouping several submarines together into a Rudeltaktik ("pack tactic", commonly called "wolfpack") to overwhelm a merchant convoy's escorts.

In the interwar years, Germany had developed ultra high frequency transmitters, (ukw) while the Enigma cipher machine was believed to have made communications secure.

[21] A 1922 paper written by Kapitäinleutnant Wessner of the Wehrabteilung (Defence Ministry) pointed to the success of surface attacks at night and the need to coordinate operations with multiple boats to defeat the escorts.

Four days later enforcement of Prize Regulations in the North Sea was withdrawn; and on 2 October complete freedom was given to attack darkened ships encountered off the British and French coasts.

Two days later the Prize Regulations were cancelled in waters extending as far as 15° West, and on 17 October the German Naval Staff gave U-boats permission to attack without warning all ships identified as hostile.

Admirals Raeder and Dönitz and the German Naval Staff had always wished and intended to introduce unrestricted warfare as rapidly as Hitler could be persuaded to accept the possible consequences.

[43] Stephen Roskill wrote, "It is now known that this operation was planned with great care by Admiral Dönitz, who was correctly informed of the weak state of the defences of the eastern entrances.

[49] Having failed to persuade the Nazi leadership to prioritise U-boat construction, a task made more difficult by military victories in 1940 which convinced many people that Britain would give up the struggle, Dönitz welcomed the deployment of 26 Italian submarines to his force.

Otto Kretschmer, Joachim Schepke, and Günther Prien were the most famous, but others included Hans Jenisch, Victor Oehrn, Engelbert Endrass, Herbert Schultze and Hans-Rudolf Rösing.

[65][66] The over-centralised command structure of BdU and its insistence on micro-managing every aspect of U-boat operations with endless signals provided the Allied navies with ample intelligence.

[49] The capture of the U-110 allowed the Admiralty to identify individual boats, their commanders, operational readiness, damage reports, location, type, speed, endurance from working up in the Baltic to Atlantic patrols.

[86] The success was achieved with only five U-boats initially[87] which sank 397 ships in waters protected by the United States Navy with an additional 23 sunk at the Panama Sea Frontier.

[86] Dönitz put the successes down to the American failure to initialize a blackout along the East Coast of the United States and ship captains' insistence on following peace-time safety procedures.

As the military situation in North Africa and on the Eastern Front began to deteriorate Hitler diverted a number of submarines to the Battle of the Mediterranean[94] upon the suggestions of Admiral Eberhard Weichold.

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.

[115] 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.

[134] 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.

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".

[140] From mid-June 1943 the technological and industrial superiority of the Allied navies allowed the Americans, Canadians, and British to form hunter-killer groups consisting of fast anti-submarine escorts and aircraft carriers.

[157] A major concern to Dönitz was Operation Overlord, the long predicted landing in France, and what role the U-boat arm and surface forces could play in the defence.

In the BdU war diary he wrote of ending operations since "otherwise the strong enemy air activity will lead to high losses which would only be acceptable if an immediate landing on the Biscay coast were expected.

[163] On 5 July 1944, the Allied Operation Dredger permitted hunter-killer groups to roam the Western Approaches and Biscay making it a "no-go area" for U-boats.

It reinforced isolated coastal garrisons along the Baltic and evacuated thousands of German soldiers and civilians in order that they might continue to participate in the war effort into the spring of 1945.

In his last will and testament, dated 29 April 1945, Hitler named Dönitz his successor as Staatsoberhaupt (Head of State), with the titles of Reichspräsident (President) and Supreme Commander of the Armed Forces.

That night, 2 May, Dönitz made a nationwide radio address in which he announced Hitler's death and said the war would continue in the East "to save Germany from destruction by the advancing Bolshevik enemy."

At Stalin's insistence, on 8 May, shortly before midnight, (Generalfeldmarschall) Wilhelm Keitel repeated the signing in Berlin at Marshal Georgy Zhukov's headquarters, with General Carl Spaatz of the USAAF present as Eisenhower's representative.

Divided along party lines, beset with the spreading poison of Jewry and vulnerable to it, because we lacked the defense of our present uncompromising ideology, we would have long since succumbed under the burden of this war and delivered ourselves to the enemy who would have mercilessly destroyed us.

[204] At the trial, Dönitz was charged with waging unrestricted submarine warfare against neutral shipping, permitting Hitler's Commando Order of 18 October 1942 to remain in full force when he became commander-in-chief of the Navy, and to that extent responsibility for that crime.