Nz406 BSM U Bunker

U-BOAT BUNKER · K.V.Gruppe Loire · AOK 7 Brittany · France

Nz406 BSM U Bunker

Nz406 BSM U Bunker

Stab Ma.FlA.820.
1 x Leitstand/SK.
1 x R630 Machine gun casemate with an armoured plate.
1 x Vf58c Tobruk.
1 x R701 gun garage.
1 x Flakstellung.
1 x 2cm Flak 28 Oerlikon.

SK/MG.
SK/MG.
A close support Tobruk with a machine gun was up on the top..
A close support Tobruk with a machine gun was up on the top..
SK/M19 Maschinengranatwerfer bunker. The bunker set into the U-Boat bunker may have been a little like an R633 type.
SK/M19 Maschinengranatwerfer bunker. The bunker set into the U-Boat bunker may have been a little like an R633 type.
428P01 M19 steel dome where a stream of 5cm mortar rounds could fire out.
428P01 M19 steel dome where a stream of 5cm mortar rounds could fire out.
4.7cm Pak K.36 Skoda (t).
4.7cm Pak K.36 Skoda (t).
Building of the Submarine Pen.
Building of the Submarine Pen.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
 

Google Maps

Nz406 BSM U Bunker

Nz406 BSM U Bunker
The first U-boat to reach St. Nazaire was U-46under Oblt. Engelbert Endrass on 21 Sept, 1940. Later this base was the home for two U-boat Flotillas, the 7th which moved from Kiel to there January to June 1941 and the 6th which came from Danzig in February 1942. The base was in full use from October 1942 and reached its peak of activity in July, August and September 1943. Also 30 air-attacks of RAF and USAAF brought only 18 slight hits on the bunker, but 62 aircraft lost. So until July 1944 Saint-Nazaire had been pounded with over 2000 tons of allied bombs, almost wiping out the town but not touching the U-boat bunker to speak of. After the allied landings in Normandy in June 1944, the 6th Flotilla was disbanded in August and the 7th Flotilla was moved to Norway. The base was declared a fortress and held out under the command of Generalleutnant Hans Junck until all German forces surrendered on May 8, 1945. Most of the remaining boats left in August and the last two in September, U-267 being the last but one on Sept 23rd. November 1944 the BdU sent two support U-boats (U-722 and U-773) to St. Nazaire. They were only armed with one torpedo for self defence and were packed with a lot of important goods and ammunition. The two boats left St. Nazaire on Dec 7th. The next two support boats were U-868 in February 1945 and U-878 in March 1945. Also U-275 stayed for two weeks in February 1945 in St. Nazaire for a Snorkel repairs. The last boat in the base was U-255 which had some damages and was in 1944 not able to leave the base. But in October 1944 a Heinkel 115 aircraft brought some spare parts and in March 1945 came the new commander Oblt. Heinrich with U-878 to St. Nazaire. The boat then made in April a patrol to La Pallice for some fuel and on the 30th April laid a mine barrier by Les Sables d'Olonne. U-255 left the base on 8 May and surrendered at sea 4 days later. When the base was entered the Type IXC boat U-510 was discovered there, having just returned from the Far East on the 23th April 1945. She was in excellent shape and was commissioned into the French Navy as S-11 Bouan in 1946 and was to remain operational until 1963. Today the bunker is mostly in private use but the Tourism office can also be found inside it.

ÜBERSICHTSPLAN d ERWEITERUBG St Nazaire. Overview plan of Enhancement St Nazaire [MFQ 1/308 St Nazaire]

Plan.
Plan.
U-Boats in the bunker.
U-Boats in the bunker.
Air photo of the bunker.
Air photo of the bunker.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Tactical target St Nazaire area by the Allies. The targets were the Ecluse sud & est where U-Boats had to enter and exit the U-Boat bunker.

Air 40/1502

Ecluse sud..
Ecluse sud..
Nz406 BSM U Bunker
Nz406 BSM U Bunker

Nz406 BSM U Bunker

Nz406 BSM U Bunker

Air 40/1502

Nz406 BSM U Bunker

Nz406 BSM U Bunker
First Floor ------Barracks & Lavatories. Ground Floor --Offices, Laboratories, Apparatus Room for Personnel (underwater escape apparatus), Guard Room, Oil Research Room.

ÜBERSICHTSPLAN d ERWEITERUBG St Nazaire. Overview plan of Enhancement St Nazaire [MFQ 1/308 St Nazaire]

Momsen lung.
Momsen lung.
Nz406 BSM U Bunker

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Allied bombing of St-Nazaire.

Allied intelligence photo.

RAF Halifax..
RAF Halifax..
USAAF Liberator..
USAAF Liberator..
RAF Lancaster.
RAF Lancaster.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
North west back of the bunker.

03 November 2015

U-Boat crew.
U-Boat crew.
Inside.
Inside.
Rommel visiting the pens.
Rommel visiting the pens.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
South west rear of bunker.

03 November 2015 Pete

Constructed between January 1940 and December 1941 by the Todt organisation..
Constructed between January 1940 and December 1941 by the Todt organisation..
Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Rear of the bunker.

03 November 2015 Pete

Christmas 1941.
Christmas 1941.
Plan.
Plan.
Parade of U-Boat crews.
Parade of U-Boat crews.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
The roof.

03 November 2015 Pete

Plan.
Plan.
U-Boat conning tower.
U-Boat conning tower.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Camouflage and the thickness of the rear wall now cut away. Note the camouflaged outer wall.

03 November 2015

Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Rear of the bunker.

03 November 2015 Pete

Plan.
Plan.
Construction on the land side.
Construction on the land side.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Rear back wall.

03 November 2015

Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Camouflage on the rear wall.

03 November 2015

Being made with its camouflage painted on.
Being made with its camouflage painted on.
Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Coming inside.

03 November 2015 Pete

Plan.
Plan.
Nz406 BSM U Bunker

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Passage to allow a railway to deliver sparers and equipment to each pen when needed. There were 62 workshops for torpedoes, engines, welding steel, periscope repairs etc, 97 warehouses for spare parts, 150 offices for supplies, 92 dormitories and rooms for crew along with kitchens, bakeries, hospitals, toilets, shower rooms etc.

03 November 2015

This is the passage.
This is the passage.
The engine may have been a small steam shunter or a diesel shunter.
The engine may have been a small steam shunter or a diesel shunter.
Nz406 BSM U Bunker

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Inside and WoW what a bunker. A 11 B pen. pen.

03 November 2015

Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
11 A pen.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
 

03 November 2015

Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
11B pen.

03 November 2015 Pete

Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
A 11 B pen.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
A 11 B pen. the view across the Bassin.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Where the U-Boats would have tied up.

03 November 2015

Vizeadmiral Dönitz at the opening ceremony the bunker.
Vizeadmiral Dönitz at the opening ceremony the bunker.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
The pens steel roof.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Its called 'Furniture'. The different types of bollards used to tie up U-Boats.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
A 11 B pen. looking outside.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
B 9 A pen.

03 November 2015

B 9 A pen.
B 9 A pen.
Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
The roof support.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Steel tie ring.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
B 11 A pen.

03 November 2015

B 11 A pen.
B 11 A pen.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
B 11 A Pen.

03 November 2015

U-Boat in side a dock.
U-Boat in side a dock.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
How it looked in here. The structure housed two flotillas of submarines and contained 14 cells, each cell allowed up to three submarines to dock. Five of the cells were also dry docks where the water could be pumped out to inspect and repair the underside of the boats.

BA

Working on a submarine.
Working on a submarine.
Wet & Dry dock.
Wet & Dry dock.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
B 9 A pens.

03 November 2015

Three in one large pen.
Three in one large pen.
U-Boat on an Atlantic cruise.
U-Boat on an Atlantic cruise.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Made in Paris this winch probably was bought from a French company stocks.

03 November 2015

Tied up.
Tied up.
Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
The port.

03 November 2015

Heading into a dock.
Heading into a dock.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
B 8 A pen, this one is right under the central flak tower. One of the dry docks with a steel shutter that can close off the entrance.

03 November 2015

Three submarines in a dry dock.
Three submarines in a dry dock.
Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
B 8 A pens shutter and runners.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
B 9 A pen.

03 November 2015 Pete

Nz406 BSM U Bunker

Nz406 BSM U Bunker
South side.

03 November 2015

Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Walking up on the roof.

03 November 2015

Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
The roof.

03 November 2015

Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
This complex of massive, interlocking concrete beams "Fangrost" was to allow heavy bombs to explode on them or ricochet of and onto the roof, thus taking a lot of energy away from the bomb. We saw no damage marks at all to the structure.

03 November 2015

Plan.
Plan.
B17's of the USAAF.
B17's of the USAAF.
Bombs increased in size from 2,000Lbs to 22,000Lps.
Bombs increased in size from 2,000Lbs to 22,000Lps.
Lancaster's.
Lancaster's.
Nz406 BSM U Bunker

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Looking under the "Fangrost" reinforced beams and as you can see, a ricochet would burst with a lot less energy.

03 November 2015

The red area is where the beams have been finished. The blue area only where only five were placed. The rest has no beams on them at all.
The red area is where the beams have been finished. The blue area only where only five were placed. The rest has no beams on them at all.
The layout of the roof "Fangrost".
The layout of the roof "Fangrost".

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Here are where only five "Fangrost" were placed and thee more should have been placed between them.

03 November 2015

The red area is where the beams have been finished. The blue area only where only five were placed. The rest has no beams on them at all.
The red area is where the beams have been finished. The blue area only where only five were placed. The rest has no beams on them at all.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
The basins entrance into the the open sea ahead where all the U-Boats came into the pens.

03 November 2015

Plan.
Plan.
Wn Nz104/Nz105 avant port rive ouest.
Wn Nz104/Nz105 avant port rive ouest.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Plan of the defences around the U-Boat bunker..

Plan

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Track fittings of a crane that ran along the roof.

03 November 2015

Plan.
Plan.
Plan of where the Flak was laid out.
Plan of where the Flak was laid out.
The crane on the roof.
The crane on the roof.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Flak.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Flak.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Flak.

03 November 2015

2cm Flak 38 Vierling.
2cm Flak 38 Vierling.
2cm magazines.
2cm magazines.
Flak.
Flak.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
The steps running up to the flak position.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
The door into the crew room and the ammunition magazine for the flak gun.

03 November 2015

Stack of ammunition boxes.
Stack of ammunition boxes.
The ammunition bunker would have been stashed full of 2cm and small arms ammunition for any machine guns that were up here on the roof.
The ammunition bunker would have been stashed full of 2cm and small arms ammunition for any machine guns that were up here on the roof.
2cm Flak ammunition magazines.
2cm Flak ammunition magazines.
Moving heavy ammunition.
Moving heavy ammunition.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
All ammunition would have to be brought up these steps.

03 November 2015

Details2
Details2

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Flak position.

03 November 2015

Nz406 BSM U Bunker

Nz406 BSM U Bunker
I have tried here to show how it may have looked with a 2cm Flak

03 November 2015

It may have been a 2cm 38 Vierling (quadruple).
It may have been a 2cm 38 Vierling (quadruple).
It may have been a 2cm 38 Vierling (quadruple).
It may have been a 2cm 38 Vierling (quadruple).

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Rear corner

03 November 2015 Pete

Flak tower on the corner.
Flak tower on the corner.
Plan of the Flak bunker on the roof under the flak position.
Plan of the Flak bunker on the roof under the flak position.
As seen from above.
As seen from above.
2cm Flak 30.
2cm Flak 30.
Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
 

03 November 2015 Pete

Nz406 BSM U Bunker

Nz406 BSM U Bunker
This shows that this portion has not been completed and the steel rods are there ready to have another layer of concrete added over it.

03 November 2015 Pete

Nz406 BSM U Bunker

Nz406 BSM U Bunker

Nz406 BSM U Bunker
A well defended corner.

03 November 2015 Pete

Plan.
Plan.
Plan.
Plan.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
7P7 plate set into the wall. Behind would have been a fighting room (gun room), ammunition and a crew room.

03 November 2015 Pete

This is how it may look inside.
This is how it may look inside.
Large slot for the gun and the smaller for the guns commander to site through.
Large slot for the gun and the smaller for the guns commander to site through.
Nz406 BSM U Bunker
Nz406 BSM U Bunker

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Details

03 November 2015 Pete

Nz406 BSM U Bunker
Nz406 BSM U Bunker

Nz406 BSM U Bunker

Nz406 BSM U Bunker
Flak tower on N/W corner.

03 November 2015 Pete

2cm Flak 38 Vierling position on roof.
2cm Flak 38 Vierling position on roof.
2cm Flak 38 Vierling.
2cm Flak 38 Vierling.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
749P3 steel turret.

03 November 2015 Pete

Position of armoured dome 749P3 type.
Position of armoured dome 749P3 type.
749P3 steel turret.
749P3 steel turret.
Where the machine gun fits.
Where the machine gun fits.
Inside a steel dome turret..
Inside a steel dome turret..
Mg34 fitted into a fortress type mounting.
Mg34 fitted into a fortress type mounting.
Fitting a steel turret in place.
Fitting a steel turret in place.

Nz406 BSM U Bunker

Nz406 BSM U Bunker
A very good picture showing the massive bomb damage to the houses here and on the left is the old railway station.

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