[tcolvin]

OK, Rainer.
If Doenitz, Raeder and Hitler had listened to Furburger, they would have given the Type XXI priority in 1940, which comes back to my posting that started this thread. Two years was the maximum the Kriegsmarine should have expected the Type VII to remain a viable weapon, and the reason it lasted for two years longer than that was Allied incompetence - lack of support for the RN by Bomber Command as mentioned critically in Richard Overy's latest book 'The Bombing War, and especially the absence of VLR patrolling.
You mention the Fuehrer Conferences. That of May 31, 1943 started with Doenitz's report: The substantial increase of the enemy Air Force is the cause of the present crisis in submarine warfare. By means of sound detection it has been determined that as many planes now pass through the narrows between Iceland and the Faroe Islands , as only recently appeared in the course of a week.
Finally, a question for you. The removal by Doenitz of Type XXI production from the K-Amt and its replacement with Albert Speer's Department of Armament and a fire-truck manufacturing wizard (Otto Merker), was bound to give problems, bombing or no bombing. It is rather too easy to blame bombing when Doenitz turned U-boat manufacturing upside down in 1943, and surely it is not surprising that in the end he got next to nothing as a result.
Tony