During World War II the principal mission of the German Navy (named the Kriegsmarine in 1935) was to seek and destroy the enemys supply routes. Under the command of Grand Admiral Raeder, responsible for its resurgence, it was above all to try and break the communication routes across the Atlantic, whose huge area would form an immense zone of operations, heavily influencing the outcome of the war.
In September 1939, with its reconstruction not yet complete, the Kriegsmarine committed all its resources to the Battle of the Atlantic. Its surface units and U-Boats (submarines commanded by the future Admiral Doenitz), set off to attack the convoys. The Norwegian campaign, one of the largest German naval deployments, provided external bases near the North Atlantic, a vital area in the guerre de course (naval attacks on the merchant marine). The occupation of the coast of France after its surrender provided a new extension to Atlantic positions. The main target was England, by then standing alone, whose strategic location was a constant threat. The Kriegsmarine attempted to isolate her, cutting off her supplies to force her to give way. She resisted, although the U-Boat crews, in a period they would call the "Happy days, were close to breaking the convoy system. But their insufficient numbers, the gradual reinforcement of the British defences and help from across the Atlantic, prevented their final success. When the war became a world war, a new period of success awaited them on the coasts of the United States. But this was cut short by the entry of the Americans into the war, as they soon provided full assistance to the British, little by little reversing the situation in the Atlantic. From hunter, the Kriegsmarine with Doenitz as its commander from early 1943, became the hunted. The large surface vessels were forced to lie low. It was considered pointless to decommission them, so they were quartered in Norway, from where the U-Boats also restarted operations after huge losses. Their efforts were concentrated on the North Atlantic, the Allied Supply route for the Russian Front where the German army was enduring heavy fighting. By early 1944 the battle had been lost.
The Kriegsmarine was pushed back little by little, its big ships immobilised, its U-Boats increasingly threatened, unable to turn the situation around. I remained on most of the coast fortified by Germany, but could do nothing to counter the landings in Norway, completed successfully by the Allies, due in part to their victory at sea. The last destroyers (Zerstörers) and torpedo boats (Torpedoboote) based in France and some U-Boats also still there, attempted to get away. Under chase, they had to withdraw, with no chance of success, as did the auxiliary vessels such as the Minensuchboote (minesweepers) blockaded in the ports and wrecked, mainly by bombing. The S-Boote (motor, torpedo boats) mostly stationed in the Channel, came close to the area of operations for a time but could do no more. The might of the Kriegsmarine was at an end. Many of its surviving vessels, incapable of returning to Germany, were scuppered in port, where, abandoned and captured, they were overtaken by the liberating forces. Crushed by Allied superiority in the skies, the Kriegsmarine stood no chance. Having fought long and bravely, at high cost but practically in vain, it disappeared in the general collapse, its last units scuppered or handed over to its adversaries. And yet, a short time earlier in the Atlantic, it had almost won the day.