For all your answers on u-boat questions: Uboat.net
Since 5 years specialised in this.
The Kriegsmarine needed also big battleships as was it only to hold the Navy back from their own merchand shipping lines and as a thread to Navy and merchanships.
Because off there simply existence you to deal with here...
The only u boats thatcould change something where the so called electro boats, type XXI and the larger XXIII (still one in Bremerhaven as a museum "Wilhelm Baur") wich could stay under like a moderen submarine and not anymore a simple submershable like the other types.
But those boats came to late.
At the last day pff the war, a XXI type could sunk the last 2 Navy ships in the war. An other electro-boat had the possibility to sink a cruiser those last days but just looked at him without firing.
All those storys are mentioned at Uboat.net , thoasands off pages with info, stories, photo's and diagrams off types and their capacities.
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