Submarine pen
Encyclopedia
A submarine pen is a bunker
which is designed to protect submarine
s from air attack.
The term is generally applied to submarine bases constructed during World War II, particularly in Germany and the occupied countries which were also known as U-boat pens (after the phrase "U-boat" to refer to German submarines).
The mid-1930s saw the Naval Construction Office in Berlin
give the problem serious thought. Various factions in the navy were convinced protection for the expanding U-boat arm was required. An RAF
raid on the capital in 1940 plus the occupation of France and Great Britain's refusal to surrender was enough to trigger a massive building programme of submarine pens and air raid shelters.
By the autumn of 1940, construction of the "Elbe II" bunker in Hamburg
and "Nordsee III" on the island of Heligoland
was underway. Others swiftly followed.
(OT) was brought in to oversee the administration of labour. Contrary to popular belief, the OT was not a 'slave' or 'forced' labour body. Workers from all over Europe and even as far afield as North Africa were recruited (particularly for the French sites), attracted by the relatively good wages and food rations. The orginisation grew from 250,000 men in 1938 to 1.4 million by the end of 1944. It was only in the second half of the war that the shortage of labour compelled the OT to recruit inmates from prisons. These individuals are easily picked out in photographs due to their distinctive black and white striped uniforms.
The local supply of such items as sand, aggregate, cement and timber were often a cause for concern. The steel required was mostly imported from Germany. The attitudes of the people in France and Norway were significantly different. In France there was generally no problems with the recruitment of men, the procurement of machinery and raw materials. It was a different story in Norway. There, the local population were far more reluctant to help the Germans. Indeed, most labour had to be brought in. The ground selected for bunker construction was no help either, usually being at the head of a fjord, the foundations and footings had to be hewn out of granite. Several metres of silt also had to be overcome.
The incessant air raids caused serious disruption to the project, hampering the supply of material, destroying machinery and harassing the workers. Machinery such as excavators, piledrivers, cranes, floodlighting and concrete pumps (which were still a relatively new technology in the 1940s), was temperamental, and in the case of steam-driven equipment, very noisy.
Bunkers had to be able to accommodate more than just U-boats; space had to be found for offices, medical facilities, communications, lavatories, generators, ventilators, anti-aircraft guns, accommodation for key personnel such as crew-men, workshops, water purification plants, electrical equipment and radio testing facilities. Storage space for spares, explosives, ammunition and oil was also required. The list seemed almost endless.
These were bunkers built over an existing lock to give a U-boat some protection while it was at its most vulnerable - i.e. when the lock was empyting or filling. They were usually constructed with new locks alongside an existing structure.
Used for building new boats
After launch, many U-boats were fitted-out under their protection
This was the most numerous type. There were two types that were built either on dry land or over the water. The former meant that U-boats had to be moved on ramps, the latter enabled the boats to come and go at will. Pumping the water out enabled dry dock repairs to be carried out. Some bunkers were large enough to allow the removal of periscopes and aerials.
There is no truth in the rumour of an underground bunker on Fuerteventura
in the Canary Islands
. This 'story' was gleaned from a similar situation in Le Havre
in France when captured U-boat men were interrogated by the British.
were located in Hamburg (Blohm & Voss), Bremen
(AG Weser
), and Danzig (F. Schichau
).
The "Hornisse" bunker was not started until 1944 in Bremen
, it was never completed.
"Valentin
", was the largest bunker in Germany. Begun in 1943, it was built to accommodate the Type XXI submarine
construction programme. It too was never completed. Post-war, the area was used as a test site for new bombs. Most of the damage done to the bunker was inflicted at this time.
Being out of range of Allied aircraft, no pens were built in Danzig (now Gdansk
in Poland).
The city was the site of two structures, "Elbe II" and "Fink II". The Finkenwerder bunker was constructed by 1,700 slave labourers over four years. After capture, it was demolished with 32 tonnes of bombs.
The "Nordsee III" bunker was one of the oldest, being started in 1940. It was left alone until near the end of the war when it was attacked by the RAF
. It was also used after the end of the war for testing new weapons. No trace of the pen has survived.
This town was constantly bombed in World War II, the targets often being the "Kilian"and "Konrad" bunkers. They were started in 1941 and 1942 respectively. The latter was used for the construction of Seehund midget submarines.
It was in "Kilian" that U-4708 was probably the only submarine to be lost in a bunker. Mis-guided bombs from an air raid on the town caused what might today be called a tsunami to cross the Förde and enter the bunker. Oberleutenant zur See Hans-Gerold Hauber, the captain of U-170 had courted ridicule by ordering all hatches on his boat to be closed, despite being in the bunker. "This simple precaution saved U-170 from sinking while lying next to U-4708".
A U-boat bunker in Wilhelmshaven was planned but never got beyond the preliminary stage.
, Brest
, La Rochelle
/La Pallice, Lorient
and Saint-Nazaire
. Almost 4.4 million cubic metres of concrete was used.
An un-named bunker and bunkered lock were constructed in Bordeaux, the fourth largest French city at the start of the war. Both structures were started in 1941; the bunkered lock was not finished by wars' end. The main building was larger than those in other locations, this was to allow supply boats and minelayers to use it. The Italian Navy established the Betasom
base at Bordeaux. The port was also the target of a British commando raid - the so-called Cockleshell Heroes
.
The Britanny port only had one bunker, but it was the largest, it was also un-named. Started in 1941, the plans were modified many times before completion a year later.
By February 1942 the RAF had lost interest in the area; most of the town had already been destroyed and they did not possess large enough bombs to seriously threaten the bunker. Between February 1942 and early 1943, apart from a few American aircraft, the place was left alone. The German garrison surrendered to US forces in September 1944. They had had sufficient explosives to cripple the bunker but did not use them due to the proximity of a hospital.
Only six kilometres separate La Rochelle and La Pallice so they are usually considered as one port. An un-named bunker was built at La Pallice, it was started in April 1941. Similar building techniques to those used in St. Nazaire were employed. Due to the relative ease of construction, the main structure was ready for its first U-boats six months later. A bunkered lock was begun in June 1942. It was completed in March 1944.
Scenes for the film Das Boot
(1981) were shot in La Pallice.
The largest U-boat base was in Lorient. Three bunkers, "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.
"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." This arrangement might have been more vulnerable to air raids, but damage was minimal and it had the advantage of the U-boat not needing a dry dock. "Keroman II", being landlocked, was served by the same system.
"Keroman III" was more conventional, as was the "Scorff" bunker. The two "Dom" bunkers, (so-called because of their resemblance to the religious building, Dom means 'cathedral' in German), were located around a massive turntable which fed U-boats into the covered repair bays.
Karl Dönitz
, head of the U-boat arm and later the chief of the German navy, had his headquarters at nearby Kernevel.
Construction of a no-name bunker was commenced in 1941. As was a bunkered lock. (But it should be noted that elsewhere in the reference, it states that "the excavations" for the bunkered lock were begun in October 1942).
The pens were not affected by the British commando raid in March 1942, whose main objective were the Normandie dock gates.
The Norwegian bunkers in Bergen
and Trondheim
were originally designed to have two floors, the lower one for U-boats, the upper one for accommodation, workshops and offices. However, with the project running six months late, plans for the second storey were abandoned.
Control of the Bergen project came under the German Naval Dockyard. Construction of "Bruno" commenced in 1941, with a Munich-based firm taking the lead. A shortage of labour was, along with the acquisition of raw materials in sufficient quantities and poor weather was always going to cause problems. Specialised machinery had to be imported, as did accommodation that could stand up to the harsh Norwegian winter.
In a bid to increase its protection, the bunker had granite blocks, each about a cubic metre in size, positioned on its roof. The shortage of cement ensured that the blocks could not be properly stuck down.
Work on "Dora II" started in 1942. It was not completed. "Dora 1
" had started the previous year, shortly after Operation Barbarossa
, the invasion of the Soviet Union. This was fortuitous, as a ready supply of Russian prisoners of war (POW)s (all volunteers), became available. Despite any number of precautions being taken when putting in the foundations, Dora I developed a noticeable sag of 15 cm (5.9 in). It did not seem to bother the submariners as much as the builders.
, details of which are shown below. The bunkers did not suffer as much as their surroundings until August 1944 when a new type of bomb was used against them, the "Tallboy".
U-boat yards and pens were the primary objectives for the US Eighth Air Force from late 1942 to early 1943. Operation Aphrodite
guided aircraft, "Bat"
guided bombs, Disney rocket-boosted bombs
, Tallboy and Grand Slam
deep penetration bombs were subsequently used to attack the U-boat pens.
Bunker
A military bunker is a hardened shelter, often buried partly or fully underground, designed to protect the inhabitants from falling bombs or other attacks...
which is designed to protect submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
s from air attack.
The term is generally applied to submarine bases constructed during World War II, particularly in Germany and the occupied countries which were also known as U-boat pens (after the phrase "U-boat" to refer to German submarines).
Background
Amongst the first forms of protection for submarines were some open-sided shelters with partial wooden foundations that were constructed during the first World War. These structures were built at the time when bombs were light enough to be dropped by hand from the cockpit. By the 1940s, the quality of aerial weapons and the means to deliver them, had improved markedly.The mid-1930s saw the Naval Construction Office in Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
give the problem serious thought. Various factions in the navy were convinced protection for the expanding U-boat arm was required. An RAF
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
raid on the capital in 1940 plus the occupation of France and Great Britain's refusal to surrender was enough to trigger a massive building programme of submarine pens and air raid shelters.
By the autumn of 1940, construction of the "Elbe II" bunker in Hamburg
Hamburg
-History:The first historic name for the city was, according to Claudius Ptolemy's reports, Treva.But the city takes its modern name, Hamburg, from the first permanent building on the site, a castle whose construction was ordered by the Emperor Charlemagne in AD 808...
and "Nordsee III" on the island of Heligoland
Heligoland
Heligoland is a small German archipelago in the North Sea.Formerly Danish and British possessions, the islands are located in the Heligoland Bight in the south-eastern corner of the North Sea...
was underway. Others swiftly followed.
General
It was soon realised that such a massive project was beyond the Kriegsmarine and the Todt OrganisationOrganisation Todt
The Todt Organisation, was a Third Reich civil and military engineering group in Germany named after its founder, Fritz Todt, an engineer and senior Nazi figure...
(OT) was brought in to oversee the administration of labour. Contrary to popular belief, the OT was not a 'slave' or 'forced' labour body. Workers from all over Europe and even as far afield as North Africa were recruited (particularly for the French sites), attracted by the relatively good wages and food rations. The orginisation grew from 250,000 men in 1938 to 1.4 million by the end of 1944. It was only in the second half of the war that the shortage of labour compelled the OT to recruit inmates from prisons. These individuals are easily picked out in photographs due to their distinctive black and white striped uniforms.
The local supply of such items as sand, aggregate, cement and timber were often a cause for concern. The steel required was mostly imported from Germany. The attitudes of the people in France and Norway were significantly different. In France there was generally no problems with the recruitment of men, the procurement of machinery and raw materials. It was a different story in Norway. There, the local population were far more reluctant to help the Germans. Indeed, most labour had to be brought in. The ground selected for bunker construction was no help either, usually being at the head of a fjord, the foundations and footings had to be hewn out of granite. Several metres of silt also had to be overcome.
The incessant air raids caused serious disruption to the project, hampering the supply of material, destroying machinery and harassing the workers. Machinery such as excavators, piledrivers, cranes, floodlighting and concrete pumps (which were still a relatively new technology in the 1940s), was temperamental, and in the case of steam-driven equipment, very noisy.
Bunkers had to be able to accommodate more than just U-boats; space had to be found for offices, medical facilities, communications, lavatories, generators, ventilators, anti-aircraft guns, accommodation for key personnel such as crew-men, workshops, water purification plants, electrical equipment and radio testing facilities. Storage space for spares, explosives, ammunition and oil was also required. The list seemed almost endless.
Types of bunker
Four types of bunker were constructed:- Covered lock
These were bunkers built over an existing lock to give a U-boat some protection while it was at its most vulnerable - i.e. when the lock was empyting or filling. They were usually constructed with new locks alongside an existing structure.
- Construction bunker
Used for building new boats
- Fitting-out bunkers
After launch, many U-boats were fitted-out under their protection
- Shelter for operational boats and repair bunkers
This was the most numerous type. There were two types that were built either on dry land or over the water. The former meant that U-boats had to be moved on ramps, the latter enabled the boats to come and go at will. Pumping the water out enabled dry dock repairs to be carried out. Some bunkers were large enough to allow the removal of periscopes and aerials.
There is no truth in the rumour of an underground bunker on Fuerteventura
Fuerteventura
Fuerteventura , a Spanish island, is one of the Canary Islands, in the Atlantic Ocean off the coast of Africa. It is situated at 28°20' north, 14°00' west. At 1,660 km² it is the second largest of the Canary Islands, after Tenerife...
in the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
. This 'story' was gleaned from a similar situation in Le Havre
Le Havre
Le Havre is a city in the Seine-Maritime department of the Haute-Normandie region in France. It is situated in north-western France, on the right bank of the mouth of the river Seine on the English Channel. Le Havre is the most populous commune in the Haute-Normandie region, although the total...
in France when captured U-boat men were interrogated by the British.
Locations
Pens were constructed in the northern coastal ports of the Reich and in many occupied countries.Germany
Pens protecting construction of the Type XXI submarineGerman Type XXI submarine
Type XXI U-boats, also known as "Elektroboote", were the first submarines designed to operate primarily submerged, rather than as surface ships that could submerge as a means to escape detection or launch an attack.-Description:...
were located in Hamburg (Blohm & Voss), Bremen
Bombing of Bremen in World War II
The Bombing of Bremen in World War II by the Royal Air Force and the Eighth Air Force targeted strategic targets in the state of Bremen, which had heavy anti-aircraft artillery but only 35 fighter aircraft in the area. In addition to Wesermünde/Bremerhaven, targets were also in Farge and...
(AG Weser
AG Weser
Aktien-Gesellschaft Weser was one of the great German shipbuilding companies, located at the Weser River in Bremen. Founded in 1873 it was finally closed in 1983. Altogether, AG Weser built about 1400 ships of different types, including many war ships...
), and Danzig (F. Schichau
Schichau Seebeckwerft
Schichau Seebeckwerft is a German shipbuilding company, headquartered in Bremerhaven. The name comes from the 1988 merger of Schichau with Seebeckwerft.-History:...
).
Bremen
The "Hornisse" bunker was not started until 1944 in Bremen
Bremen
The City Municipality of Bremen is a Hanseatic city in northwestern Germany. A commercial and industrial city with a major port on the river Weser, Bremen is part of the Bremen-Oldenburg metropolitan area . Bremen is the second most populous city in North Germany and tenth in Germany.Bremen is...
, it was never completed.
"Valentin
Valentin submarine pens
The Valentin submarine pens are a protective shelter built to construct German U-boats during World War II at Farge, a small port on the Weser River in Bremen. The pens were under construction from 1943 to March 1945 using forced labour, but were damaged by air-raids and unfinished by the end of...
", was the largest bunker in Germany. Begun in 1943, it was built to accommodate the Type XXI submarine
German Type XXI submarine
Type XXI U-boats, also known as "Elektroboote", were the first submarines designed to operate primarily submerged, rather than as surface ships that could submerge as a means to escape detection or launch an attack.-Description:...
construction programme. It too was never completed. Post-war, the area was used as a test site for new bombs. Most of the damage done to the bunker was inflicted at this time.
- Valentin: 53°13′00"N 08°30′15"E
- Hornisse: 53°07′01.5"N 08°44′04"E
Danzig
Being out of range of Allied aircraft, no pens were built in Danzig (now Gdansk
Gdansk
Gdańsk is a Polish city on the Baltic coast, at the centre of the country's fourth-largest metropolitan area.The city lies on the southern edge of Gdańsk Bay , in a conurbation with the city of Gdynia, spa town of Sopot, and suburban communities, which together form a metropolitan area called the...
in Poland).
Hamburg
The city was the site of two structures, "Elbe II" and "Fink II". The Finkenwerder bunker was constructed by 1,700 slave labourers over four years. After capture, it was demolished with 32 tonnes of bombs.
- Elbe II: 53°31′43"N 09°57′08"E
- Fink II: 53.541°N 09.854°E
Helgoland
The "Nordsee III" bunker was one of the oldest, being started in 1940. It was left alone until near the end of the war when it was attacked by the RAF
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
. It was also used after the end of the war for testing new weapons. No trace of the pen has survived.
- 54.177199°N 07.893521°E
Kiel
This town was constantly bombed in World War II, the targets often being the "Kilian"and "Konrad" bunkers. They were started in 1941 and 1942 respectively. The latter was used for the construction of Seehund midget submarines.
It was in "Kilian" that U-4708 was probably the only submarine to be lost in a bunker. Mis-guided bombs from an air raid on the town caused what might today be called a tsunami to cross the Förde and enter the bunker. Oberleutenant zur See Hans-Gerold Hauber, the captain of U-170 had courted ridicule by ordering all hatches on his boat to be closed, despite being in the bunker. "This simple precaution saved U-170 from sinking while lying next to U-4708".
Wilhemshaven
A U-boat bunker in Wilhelmshaven was planned but never got beyond the preliminary stage.
France
The German occupying forces built many U-boat pens in the Atlantic ports of France in BordeauxBordeaux
Bordeaux is a port city on the Garonne River in the Gironde department in southwestern France.The Bordeaux-Arcachon-Libourne metropolitan area, has a population of 1,010,000 and constitutes the sixth-largest urban area in France. It is the capital of the Aquitaine region, as well as the prefecture...
, Brest
Brest, France
Brest is a city in the Finistère department in Brittany in northwestern France. Located in a sheltered position not far from the western tip of the Breton peninsula, and the western extremity of metropolitan France, Brest is an important harbour and the second French military port after Toulon...
, La Rochelle
La Rochelle
La Rochelle is a city in western France and a seaport on the Bay of Biscay, a part of the Atlantic Ocean. It is the capital of the Charente-Maritime department.The city is connected to the Île de Ré by a bridge completed on 19 May 1988...
/La Pallice, Lorient
Lorient
Lorient, or L'Orient, is a commune and a seaport in the Morbihan department in Brittany in north-western France.-History:At the beginning of the 17th century, merchants who were trading with India had established warehouses in Port-Louis...
and Saint-Nazaire
Saint-Nazaire
Saint-Nazaire , is a commune in the Loire-Atlantique department in western France.The town has a major harbour, on the right bank of the Loire River estuary, near the Atlantic Ocean. The town is at the south of the second-largest swamp in France, called "la Brière"...
. Almost 4.4 million cubic metres of concrete was used.
Bordeaux
An un-named bunker and bunkered lock were constructed in Bordeaux, the fourth largest French city at the start of the war. Both structures were started in 1941; the bunkered lock was not finished by wars' end. The main building was larger than those in other locations, this was to allow supply boats and minelayers to use it. The Italian Navy established the Betasom
BETASOM
BETASOM BETASOM BETASOM (an Italian language acronym of Bordeaux Sommergibile. was a submarine base established at Bordeaux by the Italian Regia Marina Italiana during World War II....
base at Bordeaux. The port was also the target of a British commando raid - the so-called Cockleshell Heroes
Operation Frankton
Operation Frankton was a commando raid on shipping in the German occupied French port of Bordeaux in the Bay of Biscay during the Second World War. The raid was carried out by a small unit of Royal Marines known as the Royal Marines Boom Patrol Detachment , part of Combined Operations.The plan was...
.
- 44°52′11"N 0°33′31"W
Brest
The Britanny port only had one bunker, but it was the largest, it was also un-named. Started in 1941, the plans were modified many times before completion a year later.
By February 1942 the RAF had lost interest in the area; most of the town had already been destroyed and they did not possess large enough bombs to seriously threaten the bunker. Between February 1942 and early 1943, apart from a few American aircraft, the place was left alone. The German garrison surrendered to US forces in September 1944. They had had sufficient explosives to cripple the bunker but did not use them due to the proximity of a hospital.
- 48°22′00"N 04°31′20"W
La Rochelle/La Pallice
Only six kilometres separate La Rochelle and La Pallice so they are usually considered as one port. An un-named bunker was built at La Pallice, it was started in April 1941. Similar building techniques to those used in St. Nazaire were employed. Due to the relative ease of construction, the main structure was ready for its first U-boats six months later. A bunkered lock was begun in June 1942. It was completed in March 1944.
- 46°09′31"N 01°12′34"W
Scenes for the film Das Boot
Das Boot
Das Boot is a 1981 German epic war film written and directed by Wolfgang Petersen, produced by Günter Rohrbach, and starring Jürgen Prochnow, Herbert Grönemeyer, and Klaus Wennemann...
(1981) were shot in La Pallice.
Lorient
The largest U-boat base was in Lorient. Three bunkers, "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.
"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." This arrangement might have been more vulnerable to air raids, but damage was minimal and it had the advantage of the U-boat not needing a dry dock. "Keroman II", being landlocked, was served by the same system.
- Keroman I: 47°43′45"N 03°22′12"W
- Keroman II: 47°43′52"N 03°22′18"W
"Keroman III" was more conventional, as was the "Scorff" bunker. The two "Dom" bunkers, (so-called because of their resemblance to the religious building, Dom means 'cathedral' in German), were located around a massive turntable which fed U-boats into the covered repair bays.
- Keroman III: 47°43′38"N 03°22′02"W
- Scorff: 47°45′02"N 03°20′53"W
- Dom (East): 47°43′56"N 03°22′02"W
- Dom (West): 47°43′55"N 03°22′07"W
Karl Dönitz
Karl Dönitz
Karl Dönitz was a German naval commander during World War II. He started his career in the German Navy during World War I. In 1918, while he was in command of , the submarine was sunk by British forces and Dönitz was taken prisoner...
, head of the U-boat arm and later the chief of the German navy, had his headquarters at nearby Kernevel.
St-Nazaire
Construction of a no-name bunker was commenced in 1941. As was a bunkered lock. (But it should be noted that elsewhere in the reference, it states that "the excavations" for the bunkered lock were begun in October 1942).
- 47°16′33"N 02°12′09"W
The pens were not affected by the British commando raid in March 1942, whose main objective were the Normandie dock gates.
Norway
Norway is to some extent ruled by its weather. Building submarine pens was often hampered by snow and ice; the ground might have been chosen, but the occupation of France only a few months after Norway's surrender rather overshadowed the Scandinavian country as far as bunkers for U-boats was concerned. Nonetheless, a requirement for protection was identified. With the liberation of France in 1944, Norway regained its importance, but for barely a year.The Norwegian bunkers in Bergen
Bergen
Bergen is the second largest city in Norway with a population of as of , . Bergen is the administrative centre of Hordaland county. Greater Bergen or Bergen Metropolitan Area as defined by Statistics Norway, has a population of as of , ....
and Trondheim
Trondheim
Trondheim , historically, Nidaros and Trondhjem, is a city and municipality in Sør-Trøndelag county, Norway. With a population of 173,486, it is the third most populous municipality and city in the country, although the fourth largest metropolitan area. It is the administrative centre of...
were originally designed to have two floors, the lower one for U-boats, the upper one for accommodation, workshops and offices. However, with the project running six months late, plans for the second storey were abandoned.
Bergen
Control of the Bergen project came under the German Naval Dockyard. Construction of "Bruno" commenced in 1941, with a Munich-based firm taking the lead. A shortage of labour was, along with the acquisition of raw materials in sufficient quantities and poor weather was always going to cause problems. Specialised machinery had to be imported, as did accommodation that could stand up to the harsh Norwegian winter.
In a bid to increase its protection, the bunker had granite blocks, each about a cubic metre in size, positioned on its roof. The shortage of cement ensured that the blocks could not be properly stuck down.
Trondheim
Work on "Dora II" started in 1942. It was not completed. "Dora 1
DORA 1
Dora 1 is a former German submarine base and bunker built during World War II in Trondheim, Norway. Trondheim was traditionally referred to as Drontheim in German, and the name DORA is the letter "D" in the German phonetic alphabet.-Backgound:...
" had started the previous year, shortly after Operation Barbarossa
Operation Barbarossa
Operation Barbarossa was the code name for Germany's invasion of the Soviet Union during World War II that began on 22 June 1941. Over 4.5 million troops of the Axis powers invaded the USSR along a front., the largest invasion in the history of warfare...
, the invasion of the Soviet Union. This was fortuitous, as a ready supply of Russian prisoners of war (POW)s (all volunteers), became available. Despite any number of precautions being taken when putting in the foundations, Dora I developed a noticeable sag of 15 cm (5.9 in). It did not seem to bother the submariners as much as the builders.
The Allied bombing offensive
U-boat facilities first became a bombing priority in March 1941 http://www.raf.mod.uk/bombercommand/diary1941_1.html and again during the Combined Bomber OffensiveCombined Bomber Offensive
The Combined Bomber Offensive was an Anglo-American offensive of strategic bombing during World War II in Europe. The primary portion of the CBO was against German Air Force targets which was the highest priority from June 1943 to 1944...
, details of which are shown below. The bunkers did not suffer as much as their surroundings until August 1944 when a new type of bomb was used against them, the "Tallboy".
U-boat yards and pens were the primary objectives for the US Eighth Air Force from late 1942 to early 1943. Operation Aphrodite
Operation Aphrodite
Aphrodite and Anvil were the World War II code names of United States Army Air Forces and United States Navy operations to use B-17 and PB4Y bombers as precision-guided munitions against bunkers such as those of Operation Crossbow....
guided aircraft, "Bat"
Bat (guided bomb)
-External links:*...
guided bombs, Disney rocket-boosted bombs
Disney bomb
The Disney Bomb, also known as the Disney Swish, was a rocket-assisted bunker buster bomb developed during the Second World War by the British Royal Navy to penetrate hardened concrete targets, such as submarine pens, that could resist conventional free-fall bombs...
, Tallboy and Grand Slam
Grand Slam bomb
The Grand Slam was a 22,000 lb earthquake bomb used by RAF Bomber Command against strategic targets during the Second World War.Known officially as the Bomb, Medium Capacity, 22,000 lb, it was a scaled up version of the Tallboy bomb and closer to the original size that the bombs' inventor,...
deep penetration bombs were subsequently used to attack the U-boat pens.
| Target | Date | Details |
|---|---|---|
| St-Nazaire | February 15/16 1942 | 10 Armstrong Whitworth Whitley Armstrong Whitworth Whitley The Armstrong Whitworth A.W.38 Whitley was one of three British twin-engine, front line medium bomber types in service with the Royal Air Force at the outbreak of the Second World War... s and six Handley Page Halifax Handley Page Halifax The Handley Page Halifax was one of the British front-line, four-engined heavy bombers of the Royal Air Force during the Second World War. A contemporary of the famous Avro Lancaster, the Halifax remained in service until the end of the war, performing a variety of duties in addition to bombing... es; only nine aircraft bombed St Nazaire, in cloudy conditions. No aircraft were lost but three crashed in England |
| St-Nazaire | March 7/8 1942 | 17 aircraft bombed St Nazaire |
| St-Nazaire | March 25/26 1942 | Minor Operations: 27 aircraft to St Nazaire -- one Vickers Wellington Vickers Wellington The Vickers Wellington was a British twin-engine, long range medium bomber designed in the mid-1930s at Brooklands in Weybridge, Surrey, by Vickers-Armstrongs' Chief Designer, R. K. Pierson. It was widely used as a night bomber in the early years of the Second World War, before being displaced as a... lost |
| St-Nazaire | March 27/28 1942 | 35 Whitleys and 27 Wellingtons bombed German positions around St Nazaire in support of the naval and Commando raid to destroy the Nomandie dock gates in the port. The submarine pens were incidental to the raid which was aimed at preventing use of the dry-dock by capital ships. The aircraft were ordered to bomb only if the target had clear visibility. Conditions were bad, however, with 10/10ths cloud and icing, only four aircraft bombed at St Nazaire. Six aircraft bombed elsewhere. One Whitley was lost at sea |
| St-Nazaire | January 3 1943 | The first use of Lieutenant Colonel Curtis LeMay's modification of formation bombing to stagger three-plane elements within a squadron and stagger squadrons within a group was the "sixth raid on Saint Nazaire". With LeMay in command of the 305th Bomb Wing, 76 of 101 dispatched aircraft found the target and used a straight and level bomb run. Seven machines were shot down and 47 were damaged. The majority of bombs hit the submarine pens |
| Lorient | January 15 1943 | The 317th air raid on Lorient dropped 20,000 incendiary bombs |
| St-Nazaire | January 16 1943 | Two waves of B-17 Flying Fortresses inflicted major damage and killed 27 people |
| Wilhelmshaven Wilhelmshaven Wilhelmshaven is a coastal town in Lower Saxony, Germany. It is situated on the western side of the Jade Bight, a bay of the North Sea.-History:... |
January 27 1943 | The US VIII Bomber Command VIII Bomber Command The VIII Bomber Command is an inactive United States Army Air Forces unit that is better known as the later appellation Eighth Air Force, as was popularized in post-World War II filmsand is frequently called the First Eighth Air Force by its veterans and successors in the services.The command was... dispatched ninety-one B-17s and B-24 Liberator B-24 Liberator The Consolidated B-24 Liberator was an American heavy bomber, designed by Consolidated Aircraft of San Diego, California. It was known within the company as the Model 32, and a small number of early models were sold under the name LB-30, for Land Bomber... s to attack the U-Boat construction yards at Wilhemshaven. Three bombers (one B-17 and two B-24s) were shot down, only 53 aircraft actually dropped their bombs on the target due to bad weather conditions |
| Lorient | January 23 and 26 Feb 3, 4, 7, 13 and 16 Mar 6 Apr 16 May 17 1943 |
Lorient was bombed and the city was evacuated |
| Bremen Bombing of Bremen in World War II The Bombing of Bremen in World War II by the Royal Air Force and the Eighth Air Force targeted strategic targets in the state of Bremen, which had heavy anti-aircraft artillery but only 35 fighter aircraft in the area. In addition to Wesermünde/Bremerhaven, targets were also in Farge and... |
June 3/4 1943 | 170 aircraft attacked in the first large raid on Bremen since October 1941. 11 aircraft - four Wellingtons, two Halifaxes, two Avro Lancaster Avro Lancaster The Avro Lancaster is a British four-engined Second World War heavy bomber made initially by Avro for the Royal Air Force . It first saw active service in 1942, and together with the Handley Page Halifax it was one of the main heavy bombers of the RAF, the RCAF, and squadrons from other... s, two Short Stirling Short Stirling The Short Stirling was the first four-engined British heavy bomber of the Second World War. The Stirling was designed and built by Short Brothers to an Air Ministry specification from 1936, and entered service in 1941... s and one Avro Manchester Avro Manchester |-See also:-References:NotesCitationsBibliography* Buttler, Tony. British Secret Projects: Fighters and Bombers 1935–1950. Hickley, UK: Midland Publishing, 2004. ISBN 978-1857801798.... were lost. Bremen recorded this as a heavy attack, the results of which exceeded all previous raids. Housing areas were badly hit with six streets affected by serious fires. Damage to the U-boat construction yards and the Focke-Wulf Focke-Wulf Focke-Wulf Flugzeugbau AG was a German manufacturer of civil and military aircraft before and during World War II. Many of the company's successful fighter aircraft designs were slight modifications of the Focke-Wulf Fw 190.-History:... factory was described as "of no importance" but there were hits in the harbour area which damaged a pier, some warehouses and the destroyer Z-25. 83 people were killed, 29 were seriously injured and 229 slightly injured (Bremen's third heaviest casualty toll in the war) |
| Wilhelmshaven | June 11 1943 | VIII Bomber Command, Mission Number 62: 252 B-17s were dispatched against the "U-boat yard at Wilhelmshaven" and the port area at Cuxhaven; 218 hit the targets; VIII Bomber Command claimed 85-20-24 Luftwaffe aircraft, with the loss of eight aircraft and 62 damaged. American casualties were 3 KIA, 20 WIA and 80 MIA. The raid on Wilhelmshaven demonstrated the difficulty of operating beyond the range of escort fighters as enemy fighter attacks prevented accurate bombing of the target |
| Bremen and Kiel Deutsche Werke Deutsche Werke was a German shipbuilding company founded in 1925 when Kaiserliche Werft Kiel and other shipyards were merged. It came as a result of the Treaty of Versailles after World War I that forced the German defence industry to shrink... |
June 13 1943 | VIII Bomber Command, Mission Number 63: 151 B-17s were dispatched against the Bremen U-boat yards; 122 hit the target, claiming 2-2-1 Luftwaffe aircraft, with four lost and 31 damaged; casualties were eight WIA and 32 MIA. A smaller force of 76 B-17s was dispatched to the Kiel U-boat yards; 60 hit the target and claimed 39-5-14 Luftwaffe aircraft; Bomber Command lost 22 aircraft, one was damaged beyond repair and 23 were damaged. The heaviest fighter attacks to date against the Eighth Air Force accounted for 26 B-17s, mostly of the force attacking Kiel |
| St-Nazaire | June 28 1943 | VIII Bomber Command, Mission Number 69: 191 B-17s were dispatched against the "locks and submarine pens at Saint-Nazaire"; 158 hit the target. Bomber Command claimed 28-6-8 Luftwaffe aircraft, for the loss of eight B-17s and 57 damaged |
| Deutsche Werke Deutsche Werke Deutsche Werke was a German shipbuilding company founded in 1925 when Kaiserliche Werft Kiel and other shipyards were merged. It came as a result of the Treaty of Versailles after World War I that forced the German defence industry to shrink... , Kiel |
December 1943 | B-17 and B-24 bombing destroyed one workshop (100%), another workshop and storage building (80%), a factory workship and boat building (67%); a number of other buildings were damaged; a submarine under construction and workshops for engines and engineering were hit |
| Deutsche Werke, Kiel Kiel Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the... |
July 23/24 1944 | In the first major raid on a German city for two months, 629 aircraft - including 10 de Havilland Mosquito De Havilland Mosquito The de Havilland DH.98 Mosquito was a British multi-role combat aircraft that served during the Second World War and the postwar era. It was known affectionately as the "Mossie" to its crews and was also nicknamed "The Wooden Wonder"... s - were dispatched in this first RAF (since April 1943) and heaviest RAF raid of the war. In less than half an hour, all parts of Kiel were hit but the bombing was particularly heavy in the port areas and all of the important "U-boat yards" and naval facilities were hit. The presence of around 500 delayed-action or unexploded bombs caused severe problems for the rescue and repair services. There was no water for three days; trains and buses did not run for eight days and there was no gas for cooking for three weeks |
| Brest Brest, France Brest is a city in the Finistère department in Brittany in northwestern France. Located in a sheltered position not far from the western tip of the Breton peninsula, and the western extremity of metropolitan France, Brest is an important harbour and the second French military port after Toulon... |
August 5 1944 | 15 Lancasters of No. 617 Squadron RAF No. 617 Squadron RAF No. 617 Squadron is a Royal Air Force aircraft squadron based at RAF Lossiemouth in Scotland. It currently operates the Tornado GR4 in the ground attack and reconnaissance role... attacked the "Brest U-boat pens" and scored six direct hits with Tallboys penetrating the concrete roofs. One Lancaster was shot down by flak. Subsequent attempts to reinforce other sites with even thicker concrete diverted resources from other projects. |
| Lorient | August 6 1944 | The Lancaster of Tony Iveson Tony Iveson Thomas Clifford "Tony" Iveson DFC AE is a Royal Air Force pilot and veteran of World War II, and one of The Few.Iveson was born and raised in Yorkshire. -RAF Career:... dropped one Tallboy at the Keroman U-boat pen. |
| Lorient | August 7 1944 | The Tallboy bombing mission to Lorient was scrubbed |
| La Pallice La Pallice (harbour) La Pallice is the industrial harbour of the city of La Rochelle, France. It is a commercial harbour in deep water, named after the French philosopher La Pallice. The large submarine base built during World War II still stands there, although it is not being used... |
August 8 1944 | Iveson dropped one Tallboy |
| La Pallice and Bordeaux Gironde estuary The Gironde is a navigable estuary , in southwest France and is formed from the meeting of the rivers Dordogne and Garonne just below the centre of Bordeaux... |
August 11 1944 | 53 Lancasters and three Mosquitos of No 5 Group attacked "U-boat pens at Bordeaux and La Pallice" with 2,000 lb armour-piercing bombs, but the bombs did not penetrate the roofs. No aircraft were lost |
| Brest, La Pallice, and Bordeaux Bordeaux Bordeaux is a port city on the Garonne River in the Gironde department in southwestern France.The Bordeaux-Arcachon-Libourne metropolitan area, has a population of 1,010,000 and constitutes the sixth-largest urban area in France. It is the capital of the Aquitaine region, as well as the prefecture... |
August 12 1944 | 68 Lancasters of No 1 Group and two Mosquitos of No 5 Group attacked "pens at Brest, La Pallice and Bordeaux" without loss. A U-boat was believed to have been hit at La Pallice |
| Brest | August 13 1944 | 28 Lancasters and one Mosquito of No 5 Group attacked the "U-boat pens and shipping at Brest". Hits were claimed on the pens, on the hulk of an old French battleship, the Clémenceau and on a medium-sized tanker. The object of the attacks on ships was to prevent the Germans using any of the vessels in Brest to block the harbour just before its capture by American troops |
| La Pallice and Bordeaux | August 16 1944 | 25 Lancasters and one Mosquito of No 5 Group to attack the "U-boat pens at La Pallice" found the target was cloud-covered and only three aircraft bombed. No aircraft were lost |
| La Pallice | August 17 1944 | Mission 559: A B-17 dropped "Bat" Bat (guided bomb) -External links:*... guided bombs on La Pallice. One impacted 1 mile (1.6 km) short and the second about 1 mile to the right of the target |
| IJmuiden | August 28 1944 | Iveson dropped one Tallboy |
| Heligoland Heligoland Heligoland is a small German archipelago in the North Sea.Formerly Danish and British possessions, the islands are located in the Heligoland Bight in the south-eastern corner of the North Sea... |
September 3 1944 | The US Navy controller flew the Operation Aphrodite Operation Aphrodite Aphrodite and Anvil were the World War II code names of United States Army Air Forces and United States Navy operations to use B-17 and PB4Y bombers as precision-guided munitions against bunkers such as those of Operation Crossbow.... SAU-1 drone (B-24D 42-63954) into Duene Island by mistake |
| Heligoland | September 11 1944 | During the first Castor mission of Operation Aphrodite, the pilot of B-17 42-30180 (Guzzlers) was killed when his parachute failed to open on bailout |
| Heligoland | October 15 1944 | Mission 678A: Two B-17s of Operation Aphrodite attacked the Heligoland U-boat pens |
| Bergen Bergen Bergen is the second largest city in Norway with a population of as of , . Bergen is the administrative centre of Hordaland county. Greater Bergen or Bergen Metropolitan Area as defined by Statistics Norway, has a population of as of , .... |
October 28/29 1944 | 237 Lancasters and seven Mosquitos of No 5 Group attacked the U-boat pens at Bergen. The area was cloud-covered, therefore the Master Bomber tried to bring the force down below 5,000 ft but cloud was still encountered and he ordered the raid to be abandoned after only 47 Lancasters had bombed. Three Lancasters were lost |
| Heligoland | October 30 1944 | Mission 693A: One Castor Operation Aphrodite drone lost contact, went out of control and crashed near Trollhattan, Sweden. The other drone was B-17 42-3438 |
| IJmuiden | December 15 1944 | 17 Lancasters attacked with Tallboy bombs but the target was obscured by a smokescreen |
| IJmuiden | December 30 1944 | 13 Lancasters of No. 617 Squadron set out to bomb the "U-boat pens at IJmuiden" but the raid was abandoned because of bad weather |
| IJmuiden | January 12 1945 | No. 617 Squadron attacked the U-boat pens with Tallboys, but smoke obscured the results |
| Bergen Bergen Bergen is the second largest city in Norway with a population of as of , . Bergen is the administrative centre of Hordaland county. Greater Bergen or Bergen Metropolitan Area as defined by Statistics Norway, has a population of as of , .... |
January 12 1945 | 32 Lancasters and one Mosquito of No 9 and No. 617 Squadrons attacked "U-boat pens and shipping in Bergen harbour". Three Lancasters of No 617 Squadron and one from No. 9 Squadron were lost; the Germans told the local people that 11 bombers had been shot down. A local report says that three Tallboys penetrated the 3½-metre-thick roof of the pens and caused severe damage to workshops, offices and stores |
| IJmuiden and Poortershaven | February 3 1945 | 36 Lancasters attacked "U-boat pens at IJmuiden" (No. 9 Squadron) and "Poortershaven" (No. 617 Squadron) with Tallboys without loss. Hits were claimed on both targets |
| IJmuiden | February 8 1945 | 15 Lancasters of 617 Squadron dropped Tallboys on the "U-boat pens at IJmuiden" without loss |
| IJmuiden | February 10 1945 | Mission 825: nine of 164 B-17s on a 92nd Bombardment Group mission against the U-boat pens at IJmuiden, the Netherlands, first used the Royal Navy Disney Disney bomb The Disney Bomb, also known as the Disney Swish, was a rocket-assisted bunker buster bomb developed during the Second World War by the British Royal Navy to penetrate hardened concrete targets, such as submarine pens, that could resist conventional free-fall bombs... rocket-boosted concrete piercing bomb |
| Oslo Fjord | February 23/24 1945 | 73 Lancasters and 10 Mosquitos carried out an accurate attack on a "possible U-boat base at Horten on the Oslo Fjord". One Lancaster was lost |
| Bremen (Farge) Valentin submarine pens The Valentin submarine pens are a protective shelter built to construct German U-boats during World War II at Farge, a small port on the Weser River in Bremen. The pens were under construction from 1943 to March 1945 using forced labour, but were damaged by air-raids and unfinished by the end of... |
March 27 1945 | 20 Lancasters of 617 Squadron attacked the Valentin submarine pens Valentin submarine pens The Valentin submarine pens are a protective shelter built to construct German U-boats during World War II at Farge, a small port on the Weser River in Bremen. The pens were under construction from 1943 to March 1945 using forced labour, but were damaged by air-raids and unfinished by the end of... , two Grand Slam bombs penetrated two metres and detonated which rendered the shelter unusable. No aircraft were lost. |
| Bremen | March 30 1945 | 303rd BG (H) Combat Mission No. 348: 38 aircraft were dispatched to bomb Bremen. The "submarine building yards" were the first priority target (PDF) |
| Hamburg/Finkenwerder | April 4 1945 | 99.0 tonnes of bombs used http://newsgroups.derkeiler.com/Archive/Rec/rec.aviation.military/2005-08/msg00786.html |
| Hamburg Hamburg -History:The first historic name for the city was, according to Claudius Ptolemy's reports, Treva.But the city takes its modern name, Hamburg, from the first permanent building on the site, a castle whose construction was ordered by the Emperor Charlemagne in AD 808... |
April 9 1945 | 17 aircraft of 617 Squadron, with Grand Slam and Tallboy bombs, successfully attacked the "U-boat shelters". No aircraft were lost |
| Kiel | April 9/10 1944 | 591 Lancasters and eight Mosquitos of Nos 1, 3 and 8 Groups attacked Kiel. Three Lancasters were lost. This was an accurate raid, made in good visibility on two aiming points in the harbour area. Photographic reconnaissance showed that the Deutsche Werke U-boat yard was severely damaged, the German pocket battleship Admiral Scheer German pocket battleship Admiral Scheer Admiral Scheer was a Deutschland-class heavy cruiser which served with the Kriegsmarine of Nazi Germany during World War II. The vessel was named after Admiral Reinhard Scheer, German commander in the Battle of Jutland. She was laid down at the Reichsmarinewerft shipyard in Wilhelmshaven in June... was hit and capsized, the cruisers Admiral Hipper German cruiser Admiral Hipper Admiral Hipper, the first of five ships of her class, was the lead ship of the Admiral Hipper–class of heavy cruisers which served with the German Kriegsmarine during World War II. The ship was laid down at the Blohm & Voss shipyard in Hamburg in July 1935 and launched February 1937; Admiral Hipper... and the Emden German cruiser Emden The German light cruiser Emden was the only ship of its class. The third cruiser to bear the name Emden was the first new warship built in Germany after World War I.... were badly damaged. The local diary says that "all 3 shipyards" in the port were hit and that nearby residential areas were severely damaged |
| Kiel | April 13/14 1944 | 377 Lancasters and 105 Halifaxes of Nos 3, 6 and 8 Groups attacked Kiel for two Lancasters lost. This raid was directed against the port area, with the "U-boat yards" as the main objective. RAF Bomber Command RAF Bomber Command RAF Bomber Command controlled the RAF's bomber forces from 1936 to 1968. During World War II the command destroyed a significant proportion of Nazi Germany's industries and many German cities, and in the 1960s stood at the peak of its postwar military power with the V bombers and a supplemental... rated this as "a poor attack" with scattered bombing |
| Heligoland | April 18 1945 | 969 aircraft - 617 Lancasters, 332 Halifaxes and 20 Mosquitos of all groups - successfully attacked the "Naval base, airfield, & town" "almost [creating a] crater-pitted moonscape Moonscape A moonscape is an area or vista of the lunar landscape , or a visual representation of this, such as in a painting. The term "moonscape" is also sometimes used metaphorically for an area devastated or flattened by war, often by shelling.... ". Three Halifaxes were lost, the islands were evacuated the following night |
| Heligoland | April 19 1945 | No. 9 and 617 Squadrons used Tallboys against "coastal battery positions" |