The purpose of the bunker was to construct U-boats (submarines). The 9 parts of the specific U-boat, U-boat XXI, were already finished. In the bunker they would put all the parts together and then a complete U-boat would leave the bunker.
The bunker is built next to the Weser, the plan was to dig a channel to the bunker so the U-boat could easily get in and out, they never had the time to do this.
The construction of the bunker started around 1943, but the bunker was never finished. In 1945, almost 90% of the bunker was completed but not a single U-boat was constructed in the bunker.
The plan was that the U-boats would follow several construction areas and then finally arrive in the
dry-dock were they could leave the bunker. So the bunker was built in several parts, in each part a construction unit was added to the U-boat and then finally the U-boat would be complete.
Technical data:
Length-426 m
Width eastside-67 m
Width westside-97 m
Height-22 m/25 m till 30 m/33 m
Area-35.375 m2
Concrete-550,000 m3
Steel-20,000 t
Weight-12,000,000 t