August 1, 2017
On May 4, 1945 one of the most advanced submarines in the world crept up to a British Royal Navy cruiser. U-2511 was one of Germany’s new Type XXI-class “wonder” submarines, and she was hunting for Allied ships.
She also represented one of the Third Reich’s biggest failures.More than 250 feet long and displacing 1,620 tons, the Type XXI packed six hydraulically-reloaded torpedo tubes capable of firing more than 23 stored torpedoes. This arsenal could turn a convoy into sinking, burning wreckage.
But the real improvement lay deep inside the U-boat’s bowels. There rested an advanced electric-drive engine that allowed the submersible to travel underwater at significantly higher speeds—and for longer periods—than any submarine that came before.
It was perhaps the world’s first truly modern undersea warship. The engine, which was radical for its time, allowed the boat to operate primarily submerged. This is in contrast to other war-era submersibles, which operated mainly on the surface and dived for short periods to attack or escape.
But for the fortunate crew of that British cruiser, the war in Europe had just ended. Adolf Hitler shot himself on April 30. Word of the European ceasefire had also just reached U-2511. The submarine did not fire its torpedoes at the cruiser, instead merely carrying out a mock practice attack.
Neither U-2511 nor its sister ship U-3008 ever fired a torpedo in anger during the war. But the Kriegsmarine—the Nazi navy—had put its hopes in winning the naval war on these Type XXI U-boats.
http://nationalinterest.org/blog/the-buzz/why-nazi-germanys-super-submarines-were-super-failure-21738