Bordeaux U-Boat Pens

The most southern of all the Bay of Biscay bases at Bordeaux, is not actually located on the Atlantic coast, but is situated some 60 miles inland on the Gironde River, Donitz decided he wanted a Bunker facility built here, and that work commenced in September 1941.

Eventually an 11 pen structure, 7 of which had dry dock facilities, was available in a complex, 245 metres long by 162 metres wide and with a height of 19 metres. The roof had a varying thickness from 5.6 metres to about 3.6 metres over the rear servicing area.