Hornet submarine bunker
The submarine bunker Hornisse is a former building dock for the former AG Weser shipyard in Bremen , which was built during the Second World War and was to be converted into a shipyard for the construction of sections of the Type XXI submarines of the German Navy . The construction of the building dock and the no longer completed conversion to a submarine bunker were carried out with the use of forced labor .
The submarine bunker was partially preserved. It is located in the Bremen district of ports . An office building was erected on the ceiling of the bunker in the late 1960s.
location
The partially completed bunker is located in the Bremen district of Mitte, in the district of Häfen on a headland called "Cape Horn" between the Weser and the port canal "Hafen A" of the industrial ports . The bunker, which is now partially under water, is located at the small Cape Horn harbor , which is open to the Weser and thus exposed to the tidal range of the tidal river .
Today the bunker belongs to the company premises of the Lexzau company, Scharbau , which has its headquarters in an office building erected on the bunker ceiling.
history
Construction of a building dock for Großwerft AG Weser
During the Nazi era , the Bremen Großwerft AG Weser was included in the armament of the Wehrmacht ( Kriegsmarine ). The shipyard was awarded the contract for the construction of two in May 1939 battleships of the H-Class , Battleship J and N . Shortly thereafter, battleship J was keeled , but the work was stopped after a short time and battleship N was no longer laid down, as the shipyard capacities were now needed for the construction of submarines for the trade war in the Atlantic .
Before that, there were plans to expand the Bremen shipyard by two building docks because of the high level of capacity utilization, after the Navy declared its readiness to assume the costs in 1938. After the start of the war, however, as a result of the effects of the war and the increasing lack of building materials, only one building dock was built , which was planned as a dry dock and should have a length of 370 meters and a width of 65 meters.
Due to the poor condition of the subsoil, the dock floor had to be founded on a clay layer at a depth of 15 meters. The dock floor was designed with a thickness of 4 meters and made of reinforced concrete to keep the groundwater away from the dry dock and to prevent the empty dock from floating up. The 11 meter high side walls were designed with a triangular cross-section for structural reasons ; they were given a width of 6 meters at the bottom and 3 meters at the top, with vertical inner walls on the inside of the respective dock. The side walls were to be built on site in sections with the help of iron concrete formwork made of reinforced concrete.
A major construction site was set up for the construction of the dock . Among other things, track systems with a gauge of 600 and 900 mm were laid with a connection to the shipyard's own railway , which should serve to remove the excavated earth and to transport the building materials . The construction supervision for the new dock was in the hands of the Kriegsmarine, the engineering office Agatz and Bock as well as the companies Hermann Möller , Rheinische Hoch- und Tiefbaugesellschaft and Stehmeyer & Bischoff were commissioned with the planning and execution of the construction work .
The construction pit was excavated with the help of bucket chain excavators and steam-powered backhoe excavators , while the shaping of the foundation floor required extensive manual work. The construction dock towards the Weser was still closed during construction. The groundwater accumulating in the excavation had to be pumped out constantly. A total of around 621,000 cubic meters of earth was removed. After concreting the 4-meter-thick reinforced concrete base, the side walls were erected in sections from reinforced concrete with the help of formwork walls made of steel from Luchterhand . In addition, concrete foundations were made behind the main walls, which were probably intended for a later crane system .
At the end of 1942 the construction dock was about 95 percent complete when construction was stopped due to the development of the naval war .
Conversion to a submarine section yard
The German navy mainly relied on its submarine weapon and achieved successes in the Atlantic and U-boat wars from 1939 to 1942, especially against convoys. After the British decryption specialists in Bletchley Park had succeeded in breaking the code of the German encryption machine Enigma at the end of 1942 , they were able to take full advantage of their increasing air superiority and escort forces from 1943 onwards . From then on they sank numerous German submarines, in May 1943 alone there were 43 boats, whereupon the Navy temporarily put an end to the submarine war. The battle in the Atlantic had thus finally turned.
After the air raids on German shipyards increased and the production of submarines was severely restricted as a result, bomb-proof shipyards in the form of bunkers were planned. A meter-thick layer of shell was supposed to ensure that production could continue undisturbed.
Since the submarines used up to now were actually only submersibles and could not remain under water for a long time, the Navy High Command had a new type of submarine developed that could travel submerged at high speed for a long time. These type XXI submarines were equipped with powerful batteries and electric motors. They were still considerably larger than the open sea and boats of type IX and were able to snorkel operate their diesel generators to recharge the batteries. The construction of the Type XXI submarines was to be carried out using the sectional construction method known from American shipyards . At the end of 1942, the Nazi armaments minister Albert Speer commissioned the construction of one of the largest bunker yards in Bremen- Farge . The location was chosen because of the favorable infrastructural connection to the Weser, existing forced labor and the high production capacities of the Bremen shipyards.
The final assembly should take place in the submarine bunker in Rekum with the code name " Valentin ". The sections were to be manufactured in the “ Wespe ” bunker in Wilhelmshaven , among other places , and then taken by ship to the “Valentin bunker” for final assembly. In addition, the AG Weser should also manufacture submarine sections in a submarine bunker on its shipyard in the Bremen harbor and bring them to Farge by ship. In mid-1943, the submarine section bunker "Weser I" was planned for the AG Weser , for which the basin of port F of the industrial ports was to be built over with a bunker of around 160 x 110 meters. The facility should initially have six, later four, protected berths. In a second construction phase, dry construction sites with 8 or 16 helges were to be set up for protected production .
In coordination with the Todt Organization and the Naval Construction Directorate, it was decided in mid-1944 to provide the AG Weser building dock, which was not yet fully completed, with a protective cover and to convert it into a bunker system. Ultimately, a 3-stage bunker was to be created in which not only the manufacture of submarine sections, but also the repair of submarines that were damaged in use. The bunker project "Weser I" was then renamed "Hornisse".
The camouflage names were based on the initial letters of the locations: “ V alentin” came from V egesack , the location of the Vulkan shipyard. The submarine pen " W aspen" stand in W ilhelmshaven and the Bunker " H ornisse" in the Bremer H ORTS. In Hamburg- F sink werderworld the submarine pen was called " F ink II " and in K iel there was the submarine pen " K ilian ".
The submarine section bunker "Hornisse" was to consist of 4 parts with a length of 370 meters and a width of 65 meters. In the first part a two-storey workshop was to be built, while in the second part the submarine sections "3, 5 and 6" of boat class XXI were to be produced. In the third part, the repair hall was to be housed, and in the fourth part a wet dock was planned with a lock separation for the exit into the Weser. For the preparation of the bunker ceiling it was static reasons necessary to prepare an additional center wall along in the hopper to support the planned in a slab thickness of 4.5 meters protective covering of reinforced concrete. The bunker was designed with two chambers that were connected to one another by openings in the central wall.
Construction work began in spring 1944. As foundations for the center wall were compressed air - caissons filled with concrete on which then took place the building of the center wall. 3 meter high prestressed concrete girders were placed on the side and middle walls and poured with concrete piece by piece. Between the prestressed concrete girders, steel girders were installed lengthways, on which a reinforced concrete ceiling with a thickness of 1.5 meters was concreted, so that a total thickness of 4.5 meters was created.
On March 30, 1945, the port area in the west of Bremen was the target of one of the last heavy air raids on Bremen . Numerous Type XXI submarines on the Helgen were damaged by the bombs and nine of them went down in the shipyard of the AG Weser . Several bombs detonated on the bunker ceiling of the submarine section bunker "Hornisse" and severely damaged it. An aerial bomb hit a huge piece of the bunker ceiling on the corner of the south wall.
On April 6, 1945, construction work on the submarine section bunker "Hornisse" was given up. At this point in time, the bunker complex was about a quarter completed. On April 11, 1945, units of the British Army invaded Bremen and occupied all shipyards and bunkers.
Use of forced labor
As in the entire German Empire, persecution, coercion and oppression took place in Bremen during the Nazi era . Among other things, there were several concentration and labor camps in Bremen between 1939 and 1945 , the inmates of which had to do forced labor , for example at the boat yards in Grambke , the railroad marshalling yard of the Reichsbahn , at Weser-Flugzeugbau , the AG-Weser-Werft and in other port operations. All camps were satellite camps of Neuengamme concentration camp .
Forced laborers were also used in the construction work for the building dock and the later conversion to the “Hornisse” submarine bunker. They were brought in from various concentration and labor camps in Bremen, especially from the Neuenland , Osterort , Riespott and Schützenhof camps .
Around 1,200 forced laborers, prisoners of war and concentration camp prisoners were forced to work on the bunker construction site alone. As with all concentration camp and labor camp inmates, their living and working conditions were very poor and mostly inhuman. By exhaustion, hunger, cold and disease were hundreds of them died.
A memorial plaque on the bunker reminds of the suffering of the concentration camp inmates.
post war period
While the British blew up the other northern German submarine bunkers in Hamburg, Kiel and Heligoland as part of demilitarization, the Americans responsible for Bremen failed to do so. Soon after the end of the war, the bunker area came back into the possession of the city of Bremen. The Bremen Port Authority wanted to remove the bunker, but the costs were too high. Instead, the plan arose to convert the building dock, three quarters of which was not yet covered, into a small harbor basin.
These plans were only partially realized in the 1950s; Among other things, the connection to the Weser was created and the middle wall of the bunker was demolished for two thirds of its length (in the Weser-side, uncovered area). The side walls of the building dock were shortened in the uncovered area in order to bring them to the level of the new quays . On the surrounding, newly constructed quay walls as well as on the former dock walls, berths for ships were partially set up.
The use of the small Cape Horn port remained insignificant.
Partial development with an office building
In 1968 and 1969, the logistics company Lexzau, Scharbau built a larger office building on the east side of the bunker on part of the existing overburden . The company moved into it in 1969 and has since served as the headquarters of the now widely ramified logistics service provider.
The load-bearing capacity of the massive bunker structure was sufficient for the overbuilding. A ramp was built on the north wall of the bunker and parking spaces were prepared for the company's employees on the non-built-up covering of the bunker . The planning for the office building was done by the Bremen architect Gerhard Müller-Menckens .
literature
- Eike Hemmer, Robert Milbradt: Bunker "Hornet". Concentration camp prisoners in Bremen and the “AG Weser” submarine shipyard in 1944/45. Donat, Bremen 2005, ISBN 3-938275-02-2 .
Web links
- The submarine bunker "Hornisse" in Bremen-Gröpelingen
- Private pictures from the submarine bunker "Hornisse" in Bremen-Gröpelingen
- www.relict.com - The submarine bunker shipyard "Hornisse"
- Bremen submarine bunker shipyard "Hornisse" ( Memento from November 9, 2007 in the Internet Archive ) (English)
Coordinates: 53 ° 7 ′ 1.6 ″ N , 8 ° 44 ′ 3.8 ″ E
Bordeaux |
Brest |
La Rochelle |
Lorient |
Martha |
St. Nazaire
Hornet |
Elbe II |
Fink II |
Kilian |
Konrad |
North Sea III |
Rügenhafen |
Valentin |
Vistula I |
Vistula II |
wasp
