The former Nazi Germany U-boat base at Brest.
1 U-Boat Flotille moved from Kiel to Brest in june 1941 and 9 U-Boat Flotille was established here in october 1941.
Construction of the base started in january 1941 and in september 1941 the U-372 used the first ready pen. The U-boat bunkers dimensions were 333 x 192 x 17 m with an area of 52,000 square metres covered by concrete. The bunker was actually 2 structures, the first consisting of 13 pens, A to E and 1 to 8, the second of pens 9 and 10. Thickness of the roof was 3.6m in the first structure and 4.3m above pens 9 and 10; a second layer of concrete was poured over most of the roof making the best protection 6.2 metres.
The allies attacked the base and the bunker from january 1941 over 80 times and lost more than 50 aircraft in the strikes. The first successes against the base finally came in august 1944 as RAF 617th Sq attacked with Lancasters carrying Tallboy bombs. The strikes were on august 5, 12 and 13 and all in all 26 aircraft dropped Tallboys at the bunker, scoring 9 direct hits and some near-misses. Of those only 5 actually penetrated the roof and caused damage inside the bunkers but none to the U-boats! The last hastily repaired U-boat leaving Brest to Bergen Norway was U-256. Both 1 and 9 Flotillas disbanded september 1944 and all U-boat activity ceased at the base.
The base is currently still being used by the French navy!
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