August 25, 2012

Submarine Pens of the Third Reich

Photo: KaTeznik: Saint-Nazaire, This file is licensed under the Creative Commons Attribution-Share Alike 2.0 France license.

Continuing to follow my interest in the German architecture of the1930’s and 1940’s, the massive WWII Nazi Submarine pens came to my attention.  Looking at them today, many of the biggest of these still stand; the thick walls and roofs continue a fortress against an enemy long gone in time.  A little research unearthed a great deal of writing on the subject.  Articles, books, and papers abound, but none answered my top question.  Who was the architect of these impenetrable guardians and how were they built?

During the First World War, many in the German submarine fleet were cared for by tenders.  Others were protected by “open-sided shelters with partial wooden foundations.”[i]  By the mid 1930’s, warfare technology had advanced enough so the head of German Naval Command felt a need for far stronger shelters for their U Boat fleet.  The failure of the air war against Britain, the 1940 Royal Air Force raid on Berlin, plus the German occupation of France combined to trigger a massive building program of submarine pens.[ii]

They called upon the engineers of Organization Todt, (OT), to create structures that would withstand the severest bombing while serving the needs of the submarine fleet.  Fritz Todt, an engineer and Hitler’s favorite architect, had founded an engineering  business just after WWI. After coming to power, Hitler absorbed the company into the Nazi party structure, and he named the Organization after Todt.  This organization was responsible for a huge range of engineering projects both in pre-World War II Germany such as the Autobahn, and in the occupied territories during WWII such as the  Westwall (known in English as the Siegfried Line).”[iii]

“Todt…was named Reich Minister of Armaments and Munitions in 1940. In 1941 Todt and his organization (began) construction of an Atlantic wall to be built on the coasts of occupied France, the Netherlands, and Belgium.”[iv]  After Todt told Hitler that he would never win the war, he died in a still unexplained air crash in February 1942.  Hitler moved Albert Speer in to head Organization Todt and named him Reich Minister of Armaments and Munitions.

OT had taken charge of private industry and drained it of equipment and workers to build Westwall.  Now even more requisitioned equipment was moved to the Atlantic Coastline.  A third of all the concrete mixers in Germany were turned over to OT; 15,000 trucks were assigned ; the German railroads made available 6,000, later 10,000, cars a day.[v]  After Todt’s death, Speer diverted even more supplies toward this much needed project.[vi]

In the autumn of 1940, construction was begun on the "Elbe II" submarine bunker in Hamburg and "Nordsee III" on the island of Heligoland.[vii]  Soon after, work on pens up and down the Atlantic coast from Norway to the south of France began.  The largest of the bunkers was in Lorient. Three pens consisting of, "Keroman I", "II", and "III", the "Scorff" bunker and two "Dom" bunkers, east and west, were all begun in 1941. Two more were in the planning stage at the end of the war.  "Keroman I" was unique in that it required its U-boats to be "hauled out of the water, placed on a many-wheeled buggy and then transported into the bunker on a sliding bridge system.”[viii]

Four kinds of these massive shelters were constructed.  Covered-lock bunkers were built over existing locks to give a U-boat some protection when the lock was emptying or filling.  There were construction bunkers used for building new boats.  There were also fitting-out bunkers where many U-boats were fitted-out under protection while the workers got them ready to go to sea.  Finally, there were shelters for operational boats and repair bunkers which were the most numerous type.  The covered lock shelters enabled the boats to come and go at will.  Pumping the water out enabled dry dock repairs to be carried out, and some bunkers were even large enough to allow the removal of periscopes and aerials.[ix]

Hitler himself took part in the placement of these bunkers.  The architects of OT built models for Hitler to see and approve before putting the final plans into effect.  The design specifications for the construction companies involved were created by the Naval Construction Directorate of Hamburg and the OT Einsatzgruppe Hansa from Wilhelmshaven. Negotiations for the contract were also conducted by both organizations.   The association of Agatz & Bock, with offices in Cologne and Berlin, were given the job of the planning and design editing.  Their Cologne department designed almost all building and construction for the Navy. [x]  

Steel was brought from the homeland.  Some records say that cement and aggregate were supplied by the occupied territories, but at the Norwegian pens all cement, aggregate, and steel were brought in.

OT’s expansion needed labor, and most Germans were not drawn to work for low pay in construction.  “Those Germans it did employed had an average age of 53.  Some 80% of the OT's members were young non-Germans, many of them volunteers taken in by clever propaganda. But most were forced labour and prisoners-of-war (POW) in positions that were little better than those in the concentration camps.”[xi]

Ted Chile writes in his blog, “Ted's Excellent Trondheim Adventure,” in Norway “the Dora complex was constructed under the management of the Nazi Todt organization.  While not under Albert Speer’s direction, the great “architect” of many of Nazi Germany’s most durable structures, he was the executive who made sure this job was completed in 1943.”[xii]

Chile states, “Five million 50-pound sacks of German concrete were used to construct Dora.  All the concrete and reinforcing steel used in the building came from Germany (as) the Nazis did not trust the quality of local products for use in these structures, and there was always a potential for sabotage of the local materials as well.  Modern (for the time) construction techniques were used to complete Dora–wet concrete was pumped to the site to help create walls ranging from 2.5 meters to 10 meters thick within this building.  Problems with the integrity of the sea-bed underneath the sub-pen required that it be made to “float” on the bottom of the Trondheim harbor…and, so it does.”

“Norwegians had not, to this time” Chile continues, “seen construction techniques like the ones used to build Dora, but they learned from the Germans as they worked on this and other structures.  Slave labor was used extensively on this project…”

The land surrounding each Atlantic coast submarine pens created its own architectural needs.  In Hitler’s Northstar, a created city north of Trondheim, pens were blasted into the side of a mountain.  In the Keroman peninsula, the rock was so hard that a slipway and dry pen arrangement were created. 
An excellent example of the covered lock type bunker are the locks at Saint-Nazaire.  Following the surrender of France to Germany, a heavily fortified U-boat submarine base was built by OT at Saint-Nazaire shortly after the German occupation.  With its 9 m (30 ft) thick concrete ceiling, this pen was capable of withstanding almost any bomb in use at the time.  The sub base still stands today, as its extremely sturdy construction makes demolition uneconomical. The base is now used by cafes, a bar, yacht clubs, and on the roof is an exhibition about Saint-Nazaire.[xiii]
In January of 1943, the Allies implemented incendiary bombing tactics against U-Boat pens along the Atlantic coastline.  To cut the number of casualties in Saint-Nazaire, the British Royal Air Force and American aircraft dropped scores of leaflets in the surrounding area before the raids.  They repeatedly warned the population of a planned fire-bombing raid. By the end of the third day, the Allies attacked and burned the entire city to the ground. Casualties were light as most of the civilians had heeded the warning and fled to the safety of the countryside where they were not always welcome.  After that, except for the self-contained U-boat base, the city of Saint-Nazaire remained abandoned until the end of the war.
“After D-day and the liberation of most of France in 1944, German troops in Saint-Nazaire's submarine base refused to surrender, and they holed up (as did their counterparts in the La Rochelle and Lorient bases).” Since the Germans could no longer conduct major submarine operations from the bases without a supply line, General Dwight D. Eisenhower decided to simply go around these three ports, and focus the Allied resources on the invasion of Germany. “Saint-Nazaire and the other two German "pockets" remained under Nazi control until the last day of the war in Europe, 8 May 1945.”[xiv]
Recently there have been a number of books published on the subject of submarine pens.  I’m not shy about beginning a search for a copy of "HITLER'S U-boat Bases" by Jak P Mallmann Showell or “Hitler’s U-boat Fortresses” by Randolph Brabham.   “German U-boat bunker yesterday and today”, arsenal Volume 11, Karl-Heinz and Michael Schmeelke, Schiffer Publishing, 2001 has been very useful.  These volumes hopefully will have the architectural details that the online articles lack.  Maybe someday I will discover the actual team of architects that designed these massive submarine bunkers for Organization Todt.
Fortunately, I cannot separate the creation from the construction.  The author of the “ writes, “bunker Shipyard "Valentin" had between ten thousand and twelve thousand people working there every day.   Most of the workers were (prisoners of war, concentration camp inmates, or "civilian" foreign workers). The German skilled workers, guards, supervisors and engineers at the site lived and worked on site.  During the construction of the submarine bunker the employed forced laborers were housed in seven different camps within three to five miles from the site.  Least four thousand of the laborers deployed at the site died by exhaustion, abuse, disease and malnutrition. [xv] 
These deaths and horrors slowed my curiosity about the design and construction details, and I am left with only dullness and anger.

1 "HITLER'S U-boat Bases" Jak P Mallmann Showell 2002 Sutton Publishing ISBN 0-7509-2606-6 p. 1 from,
6   Army Talks, 1943
7 Todt military organization

* Apologies for the messed up end notes, but I include them just in case you wish to follow up on a point.  This was my first time using them in Word.


  1. An "o-o-oh" moment: it's a person. When I saw Todt, I thought it was an old-fashioned spelling for Tot, which is death.

    Some of my German books are so old, they're in the old German font. I liked it when I learned it, but I find I've largely forgotten it now.

  2. Two comments:
    1/ I am sure you have read Albert Speer's 'Rise and Fall of the Third Reich';

    2. I am sure you have seen Wolfgang Pederson's "Das Boot."

    I never knew about the submarine pens. I guess they have to put them somewhere.


  3. I am now reading Operation Mincemeat and find this little add on interesting. Viewing this war from a distance is like seeing it through Valium. The book is more light-hearted.


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