Is this a true statement about the B24?

[Rainer]

Tony, the developement of the type XXI is explained in detail in a book written by the renowned author Eberhard Rössler but as far as I know it was only published in German. I don't know which sources Lienau used for his article, but it is simply not possible that the idea for the type XXI existed in 1941 because it was based on the type XVIII which was designed by Walter in mid 1942.

The projected production by the K-Amt calculated with 18 months to built a type XXI while Speer/Merker promised to shorten that time to 6 months. So guess what was more important for Dönitz after the submersibles were defeated in May 1943 - to get the new design operational as fast as possible or to get as many as possible?

Is the last sentence under point 20 in your post about the USSBS report from you or is that stated in the report itself? Because it is misleading... the first type XXI was commissioned in June 1944 and 119 were delivered until March/April 1945 when the production practically ceased due to air attacks mentioned under point 17 of the USSBS report. To call the Speer/Merker method a failure does not take in account that the conventional U-boat building method would have produced less than 20 type XXI U-boats until March/April 1945.

The first type XXI became operational in April 1945 about 11 months after the first U-boat of this type was delivered to the Kriegsmarine. There were different reasons for this, a logical one is that every new design has teething troubles. A major one was that the training of a type XXI crew took twice as long as the training of a type VII crew (6 to 7 months compared to 3 to 4 months) due to the many new technolgies introduced with the type XXI and the complexity compared to the type VII. Another problem was that the training area in the Baltic Sea was heavily mined by the Bomber Command and eventually lost when the Red Army reached East Prussia in January 1945.

In fact you seem to agree with this by writing that "The U-boats had already practically lost the convoy battles in late 1941", and yet Doenitz did not see the danger signal.

Dönitz was well aware of the problems after the desastrous battle against convoy HG-76 in December 1941. This convoy was escorted by HMS Audacity, one of the first escort carriers and its aircraft showed how the the wolfpack tactics employed by the submersibles could be beaten. Thats why he held a meeting with Walter in January 1942 to plan the construction of the first operational U-boats with Walter propulsion - the types XVIIA & XVIIB.