U-boat base

In the summer of 1941 it was decided to build the fifth U-boat bunker in France. The initial construction was finished in May 1943 and took 7.000 workmen. The bunker provided space for 15 submarines: 8 in double boxes 1 till 4 and 7 in the single boxes 5 till 11. The boxes together measure 245 m wide, 165 m deep and have an average height of 19 m. The adjacent building has the dimensions of 28 x 73 x 23 m. In total 600.000 cubic meters of concrete were used. The roof was built in "A", so 3,5 m and later on reinforced with a second layer of 2,1 m. In the end it was finished off with a row of concrete beams. This work on the "Fangrost" was (almost) done in August 1944.

The harbor of Bordeaux is an open one, so locks have to regulate the waterlevel. In order to protect the U-boat during the long periode of levelling, a lockbunker was constructed. The bunker itself was finished, but due to an instable soil, the lock itselves never became operational. The lockbunker was demolished in 1947.

Behind the UBB there is a big bunker for fuel. It could contain over 4.000.000 liters. The supply U-boats, which brought the fuel for the operational U-boats far onto the ocean, were stationned at Bordeaux. They were called "milch-cows". The storage bunker was connected to the base with an underground pipeline system.

The last layer of the roof protection was almost finished.