Picture I https://pimeakronikka.blogspot.com/p/why-germans-made-type-xxi-class.html Kimmo Huosionmaa This is the text about Type XXI Walther turbine boats, not Type XXI electro beats, what were equipped with the conventional diesel-electric system was produced 114 units. So if here is mentioned the XXI-U-boat it means the Walther boat. And I don't know about winnings of this type of submarines. Some The Type XXI U-boats served in allied navies after the World War II and their mission was to help to create new submarines for the U.S and the other allied navies. https://uboat.net/types/xxi.htm The reason for German secret military projects is simple, the losses of the U-boats and aircraft were so big, that the Nazi-government must try to create new kind of equipment for replacing the old things. The losses of the U-boats were grown very high, and that was the reason for creating the new type of submarines. Type XXI was the fiasco in many ways because the technology
For finding solutions for problems, we must not claim that some proposition is right or wrong. All possibilities are open. Until they are proven right or wrong using empiric methods that are scientifically accepted.