German Type XXI Submarine - Construction

Construction

Between 1943 and 1945, 118 boats were assembled by Blohm & Voss of Hamburg, AG Weser of Bremen, and F. Schichau of Danzig. Each hull was constructed from eight prefabricated sections with final assembly at the shipyards. This new method could have pushed construction time below six months per vessel, but in practice all the assembled U-boats were plagued with severe quality problems that required extensive post-production work to fix. One of the reasons was, as a result of Albert Speer's decision, sections were made by companies having little experience in shipbuilding. As a result, of 118 Type XXIs completed, only four were fit for combat before the war ended in Europe.

It was planned that final assembly of Type XXI boats would eventually be carried out in the Valentin submarine pens, a massive, bomb–hardened concrete bunker built at the small port of Farge, near Bremen. Construction took place between 1943 and 1945, using around 10,000 concentration camp prisoners and prisoners of war as forced–labour. The facility was 90% completed when, in March 1945, it was badly damaged by Allied bunker buster bombs and abandoned. A few weeks later, the area was captured by the British Army.