There was indeed a U-boat recovered and taken to Neptun Werft at Rostock in 1956, but this was U-929 that had been scuttled off Warnemünde at the end of the war and was subsequently broken up. It had been the first of four of the improved type VIIC/41 that were built by the Neptun Werft, but only the first two were finished.

So there seems to be some truth in this released CIA report, but most of it is inaccurate or simply wrong - "appraisal of content is tentative".

Best regards
Rainer

Crew member of uboat.net