Valentin submarine pens

Coordinates: 53°13′00″N 8°30′15″E / 53.2167°N 8.5042°E / 53.2167; 8.5042 (Submarine Bunker Valentin Memorial)
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Valentin Submarine Factory
Part of Third Reich
Rekum [de; nds] port (Weser River, Bremen)
Luftbild Bunker Valentin.jpg
Aerial view of Valentin (2012)
Coordinates53°13′00″N 8°30′15″E / 53.2167°N 8.5042°E / 53.2167; 8.5042 (Submarine Bunker Valentin Memorial)
Site information
Open to
the public
Free entrance, self guided walking tours, electronic audio guide available
Site history
BuiltFebruary 1943 to March 1945 (unfinished)
MaterialsFerrous concrete

The Valentin submarine factory is a protective shelter on the Weser River at the Bremen suburb of Rekum [de; nds], built to protect German U-boats during World War II. The factory was under construction from 1943 to March 1945 using forced labour, but was damaged by air-raids and unfinished by the end of the war. The Valentin factory was the largest fortified U-boat facility in Germany, and was second only to those built at Brest in France.

As a manufacturing facility, it differed from conventional U-boat pens, which were designed to house and service operational U-boats.


A roof truss of U-boat bunker "Valentin" is lifted into place (1944)

Production of U-boats by German shipyards had been dramatically reduced as a result of bombing by the Royal Air Force and the United States Army Air Forces, necessitating the creation of bomb-proof production sites. Many such sites were in use in 1944, including the U-boat pen Nordsee III on the German island of Helgoland, Fink II and Elbe II in Hamburg and Kilian in Kiel. Other sites in Germany and other occupied countries were under construction or planned, such as Hornisse in Bremen, Elbe XVII and Wenzel in Hamburg, Wespe in Wilhelmshaven, Kaspar in Kiel. Under the codename Valentin a submarine factory was to be built directly on the Weser river between the Bremen suburbs Rekum and Farge. It was intended the facility would be used for the final assembly of Type XXI submarines, starting in April 1945 with three boats and from August 1945 a monthly delivery of a minimum of 14 boats. A second bunker called Valentin II was planned as well.[citation needed]

The bunker is around 426 metres (1,398 ft) long and 97 metres (318 ft) wide at its widest point; the walls are 4.5 metres (15 ft) thick. The height of the structure is between 22.5 and 27 metres (74 and 89 ft). The roof was constructed using dozens of large, reinforced concrete arches, manufactured on-site and individually lifted into place. Most of the roof is around 4.5 metres (15 ft) thick but part of it is 7 metres (23 ft) thick as the Germans began adding to its thickness before the bunker was even completed. Construction required 650,000 cubic yards (500,000 m3) of concrete.[1]

The design and oversight of the Valentin's construction was carried out by the Organisation Todt. Marineoberbaurat Edo Meiners was in charge overall; the on-site supervising engineer was Erich Lackner.[2] He had a lengthy post-war career, becoming one of Germany's most prominent civil engineers.[citation needed]

By March 1945, the facility was 90% completed and the most of the necessary machine tools had been installed. Production of U-boats was due to begin within two months.[3]

Planned use[edit]

Plan of Valentin, taken from the 1946 US Air Force report on the results of Project Ruby[1]

After completion, the bunker would have had a work–force of around 4,500 slave workers.[4] Under the management of the Bremer Vulkan shipyard, it would assemble U-boats. Each would be built from eight, large, pre-fabricated sections manufactured in other shipyards such as Bremer Vulkan, Deschimag AG Weser with its bunker Hornisse, Kriegsmarinewerft Wilhelmshaven with bunker Wespe and Deschimag Seebeckwerft in Bremerhaven, and then shipped to Valentin on barges.

The bunker was to house 13 assembly bays (called Taktplatz in German, or Takt for short), each carrying out one part of the assembly process. Two bays, Takt 9 and Takt 10, were underneath box-like structures on the roof that allowed the extra height needed for the installation of periscopes, snorkels and antennas. The two last bays, Takt 12 and Takt 13, were separated by high walls from the rest of the building and could be closed by water-tight floodgates. Takt 13, the final bay, was a dry dock with an 8-metre (26 ft) deep pool of water. The two separated bays could be flooded to give a total water depth of about 20 metres from the bottom of Takt 13's dry dock to the water-surface at the building's roof-level. Takt 13 was to be used for leak–tests of the completed U-boats as well as engine starts and other tests. In addition to the 13 assembly bays, the bunker housed workshops and store-rooms for the prefabricated sections, diesel-engines and batteries, and storage tanks for fuel and lubricants.

The gateway in the western wall could be closed by means of a sliding bomb-proof door which opened to a small canal, a creek and then directly onto the Weser river. Through this, sections of submarine would be delivered by barges and completed submarines could leave.[1]

Operations at Valentin were intended to commence by late 1944, but was postponed to mid-1945 due in part to a combination of manpower and supply shortages and bombing. It is likely that production would have been limited due to the severe quality control problems experienced with the prefabricated sections. Albert Speer (the Reich armaments minister) had directed that the sections be made by inland companies and then assembled at the shipyards so as to ease production. However, these companies had little experience in shipbuilding resulting in lengthy re-working to rectify flaws in the sections. Out of the 118 boats completed, only four were rated fit for combat before the war ended in Europe.[5]

Labour force[edit]

The partially completed Valentin bunker in 1944 and some of workforce of forced labourers

Most of the 10,000–12,000 people who built Valentin were slave workers,[6] who lived in seven camps located between 3 and 8 kilometres (1.9 and 5.0 mi) from the bunker. Some were housed in the nearby Bremen-Farge concentration camp, the largest subcamp of the Neuengamme concentration camp complex, with 2,092 prisoners as of March 25, 1945.[6] The camp facility was erected close by at a large naval fuel oil storage facility; some prisoners were accommodated in an empty underground fuel tank. Among the labourers were mainly non–German concentration camp inmates (Fremdarbeiter) as well as Russian, Polish, and French prisoners of war,[6] but also some German criminals and political prisoners.[Note 1]

The camp was initially run by the SS, but the expansion of the camp network in the area led to a shortage of personnel. By mid-1944, the camp was commanded by an army captain, Ulrich Wahl, and the prisoners were guarded by a detachment of naval infantry.[6] Only a handful of SS men remained involved in the running of the camp.[6]

Work on the bunker took place around the clock, with personnel forced to work 12-hour shifts from 7am to 7pm. This resulted in a high death rate amongst the prisoners. However, the identity of only 553 victims, mostly Frenchmen, has been confirmed.[6] The total number of deaths may be as high as 6,000 as the names of the Polish and Russian dead were not recorded. The worst work on the site was that of the so-called iron detachments (Eisenkommandos), responsible for the movement of iron and steel girders. A French survivor, Raymond Portefaix, stated that a prisoner's life expectancy fell dramatically on being assigned to one of these detachments. He described the Eisenkommandos as suicide squads.[6]

The prisoners held at the Neuengamme concentration camp and its subcamps were evacuated in April 1945, just before the capture of the area by the British army. Many were placed on board the SS Cap Arcona. This German ship was heavily laden with around 5,000 concentration–camp prisoners when she was attacked and sunk by the RAF on 3 May 1945; only 350 prisoners survived.[7] The sinking took place just one day before the German surrender at Lüneburg Heath, the unconditional surrender of German forces in the Netherlands and North-West Germany. It is estimated that more than 6,000 workers died during the building of Valentin.


An RAF officer examines the crater produced by the March 1945 Grand Slam bomb strike
Interior of Valentin – the figure standing on the pile of rubble gives scale

The Valentin factory was attacked by the RAF on 27 March 1945. The attacking force consisted of twenty Avro Lancaster heavy bombers of 617 Squadron which had, after the "Dambusters" raid, developed precision bombing methods. Simultaneously, a force of 115 Lancasters bombed the nearby fuel oil storage depot in the village of Schwanewede. The bombers were escorted by ninety RAF North American Mustang fighters of 11 Group[3]

The Lancasters attacking Valentin each carried a single large earthquake bomb – seven carried the 5 ton 'Tallboy', thirteen carried the 10 ton 'Grand Slam'. Two 'Grand Slam's hit the target and penetrated about half-way through the 15-foot (4.6 m) thick ferrous concrete roof before exploding. The explosions blew large holes in the remaining thickness of the roof and brought down around 1,000 tons of debris into the chamber below.[8] Workers who were inside the bunker at the time survived, as the bombs did not penetrate the roof before detonating.[8] Another bomb caused damage to a nearby electricity plant, workshops and a concrete mixing plant.

Fortunately for the British, the two bombs struck and penetrated the 4.5-metre (15 ft) thick west section of the roof. Post–war American analysis suggested the 7-metre (23 ft) thick, east section would have been able to resist even the Grand Slams, although not without significant damage, and it is unlikely that it would have survived repeated hits.[8]

Three days later, on 30 March, the US Eighth Air Force attacked Valentin with Disney bombs. These were large (4,500 lb (2,040 kg)) weapons with hard steel casings, rocket-assisted to increase their penetrating power. Sixty were launched but only one hit the target, causing little damage.[8] However, considerable damage was done to installations surrounding the bunker.

The factory was abandoned, and four weeks after the bombing, the area was occupied by the British Army's XXX Corps, which captured Bremen after a five-day battle.[8]

Post war[edit]

Eastern and southern side of Valentin
The 1983 memorial, Vernichtung durch Arbeit, commemorating the deaths and suffering of those who built Valentin

After the war, when the machine tools had been removed, further bombing of Valentin was carried out. Beginning in March 1946, Project Ruby was a joint Anglo-American affair to investigate the use of penetration bombs against heavily protected concrete targets.

The U-boat pen Nordsee III and subterranean bunkers on the island of Heligoland were also selected as targets for this testing. Bombs were carried by Avro Lancasters from No. 15 Squadron RAF and US Boeing B-29 Superfortress and Boeing B-17 Flying Fortress aircraft operating from RAF Marham. Around 140 sorties were flown, testing a range of different bombs.[9]

Because it seemed impossible to destroy Valentin by bombing it, the decision was made to destroy it by blasting. This idea was later abandoned because the blasting would have caused severe damage to the nearby villages of Rekum and Farge including the power-station in Farge. In 1960 the bunker was taken over by the German Navy, for use as a storage depot.

In 1983, a memorial to the workers who built Valentin was erected. Titled Vernichtung durch Arbeit (Extermination through labour), it was by Bremen artist Fritz Stein.[10]

High maintenance costs forced the German Defence Ministry to offer the bunker for sale in 2008.[11] Military use finally came to an end on 31 December 2010. Its custodianship was passed to a group called Denkort Bunker Valentin with the intention of developing it as a museum and a memorial. The group currently offers guided tours of the bunker to the public.[12]

See also[edit]


  1. ^ These were befristete Vorbeugungshäftlinge ("temporary preventive custody prisoners"); some were prisoner functionaries. The "Camp Elder" was Erich Meissner, a German political prisoner (described by another ex–prisoner as a brutal alcoholic), who became mayor of Leipzig post–war. See Neuengamme / Bremen-Farge, United States Holocaust Memorial Museum.


  1. ^ a b c Comparative Tests of the Effectiveness of Large Bombs Against Reinforced Concrete Structures (Anglo-American Bomb Tests – Project Ruby) (PDF) (Report). Headquarters, Air Proving Ground Command Elgin Field, Florida. 1946. p. 91. Archived (PDF) from the original on 28 June 2011. Retrieved 15 February 2011.
  2. ^ Lehmann (1999). 100 Jahre schiffbautechnische Gesellschaft (in German). Springer. p. 214. ISBN 3-540-64150-5.
  3. ^ a b Flower 2004, p. 349.
  4. ^ "Bunker Valentin" (in German). U-Boot-Bunker Valentin, Documentation and Memorial Association. Retrieved 22 April 2011.
  5. ^ Tooze, Adam (2006). The Wages of Destruction. London, UK: Penguin Books. pp. 616–18. ISBN 978-0-14-100348-1.
  6. ^ a b c d e f g Buggeln, Marc. "Neuengamme/Bremen-Farge". Holocaust Encyclopedia. United States Holocaust Memorial Museum. Retrieved 29 January 2011.
  7. ^ Vaughan, Hal (2004). Doctor to the Resistance: The Heroic True Story of an American Surgeon and His Family in Occupied Paris. Brassey's. pp. 154–156. ISBN 1-57488-773-4.
  8. ^ a b c d e Flower 2004, p. 351.
  9. ^ "Bombs Versus Concrete". Flight: 537–41. 30 May 1946. Retrieved 28 January 2011.
  10. ^ Beschreibung Archived 2012-03-09 at the Wayback Machine auf der Homepage des KZ Neuengamme.
  11. ^ Boyes, Roger (19 March 2008). "Notorious German Third Reich U-boat base Valentin for sale to serious bidder". The Times. Retrieved 27 January 2011.
  12. ^ "Denkort Bunker Valentin". DE.

Further reading[edit]

  • Michèle Callan: Forgotten Hero of Bunker Valentin. Die Geschichte von Harry Callan. Edition Falkenberg: Rotenburg/Wümme 2018
  • Engelbertz, Susanne (1992), Heimatgeschichtlicher Wegweiser zu Stätten des Widerstands und der Verfolgung 1933–1945 – Bremen [A local history guide to pläces of resistance and persecution 1933–1945 – Bremen] (in German), vol. 6, Verlag für Akademische Schriften, ISBN 3-88864-040-7.
  • Flower, Stephen (2004), Barnes Wallis' Bombs, Tempus, ISBN 0-7524-2987-6.
  • Grube, Christel, Uboot-Bunker Valentin, Bremen-Farge (in German), 28 February 2006: Lost{{citation}}: CS1 maint: location (link).
  • Johr, Barbara; Roder, Hartmut (1989), Der Bunker, Ein Beispiel nationalsozialistischen Wahns, Bremen-Farge 1943–45 [The Bunker, An example of national socialistic insanity] (in German), Bremen: Temmen, ISBN 3-926958-24-3.
  • Rössler, Eberhard (1996), Geschichte des deutschen U-Bootbaus (in German), vol. 2, Bonn: Bernard & Graefe, ISBN 3-86047-153-8.
  • Valentin Submarine Assembly, Farge, Germany: Date of Survey, July 1947. Vol. 179. U.S. Strategic Bombing Survey, Physical Damage Division. 1947.

External links[edit]