Dunkerque class
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The Dunkerque- class was a class of capital ships in the French Navy . With the Dunkerque and the Strasbourg, only two ships belong to it, which were developed and built in the 1930s. The first draft sketches were made in 1926. Its construction was part of the extensive modernization efforts of the French Navy after the First World War .
With a standard displacement of 27,000 tons for their time rather small battleships , they were the only modern battleships in France at the outbreak of World War II . Due to the course of the war, they were rarely used. You were involved in the attack by the British fleet on Mers-el-Kébir , in which the Dunkerque was badly damaged. Both ships were sunk by their crew in 1942 .
Design history
After the First World War, the French battleships, like the rest of the French fleet, were severely outdated. France - like Italy, whose battle fleet was in a comparable condition - was therefore granted the right in the Washington Naval Agreement to have one ship each of a maximum of 35,000 tons in 1927 and 1929 . l. Standard displacement to keel.
The French fleet, however, was not convinced of the usefulness of such large ships; In addition, the infrastructure necessary for the construction was missing. France therefore reserved the right to use the 70,000 tn. l. to use for more than two ships. The first building considerations in 1926 related to a ship of 17,500 ts, known as a “croiseur de combat” (literally battle cruiser ). With eight 30.5 cm guns, a speed of 35 knots and armor designed against 20.3 cm guns, it was supposed to be superior to heavy crosses and in particular to protect the French sea connections against the ships of the Italian Trento class .
However, the French Navy had doubts about this concept. The ships would have used part of the battleship tonnage available under the Washington Naval Agreement, but would have been inferior to real battleships. In addition, it was not yet clear whether and how the Italian Navy wanted to replace its battle fleet. The French Navy therefore undertook further design studies, with the “Conseil Supérieur de la Marine” decreed that the standard displacement of the designs was an integral factor of the total tonnage of 175,000 t agreed in Washington. nl. should be.
In December 1928, the characteristics of the Germany class became known. The need to armor the new ships against their 28 cm guns concluded a draft of 17,500 tons. l. finally out of the considerations. Studies on a draft of 23,333 tn. l. (three ships within the scope of the contractually directly available 70,000 tn. l.) ultimately led to a 26,500 tn. 1st draft, which was to form the basis for the Dunkerque class. The caliber of the main armament was increased from 30.5 cm to 33 cm and the armor was reinforced so that it not only provides protection against the 28 cm shells of the Deutschland class, but also against the 30.5 cm. Offered shells of the not yet modernized Italian battleships.
The construction of the Dunkerque class meant that the Reich and Kriegsmarine no longer continued the Germany class and built the Scharnhorst class .
In response to the construction of the Dunkerque , the Italian Navy began modernizing the Conte-di-Cavour class . The French decision to lay a second ship on the keel led to the construction of two officially 35,000 tonnes after failed Franco-Italian negotiations on the part of the Italian Navy. l. displacing battleships ( Littorio- class ). This in turn led the French Navy to consider replacing the second ship of the class, the Strasbourg , with a ship of 30,000 tn. l. or 35,000 tn. l. to replace. Since this would probably have delayed the completion of the second ship by 15 to 18 months and the construction had already been prepared, they contented themselves with a certain reinforcement of the armor protection, which increased the displacement to 27,300 tn. l. let rise.
In response to the Littorio class, the French Navy further developed the Dunkerque design into the Richelieu class .
technology
The design of the Dunkerque class was strongly influenced by the British Nelson class , in particular with regard to the arrangement of the main armament with the aim of keeping the length of the armored area (“ citadel ”) as short as possible.
If the information given below for the Strasbourg differs, this is indicated in the table below.
The Dunkerque- class had a normal displacement of 30,750 tons and a maximum displacement of 35,500 tons. The overall length was 215.14 m, the width 31.1 m and the draft 8.57 m with normal and 9.71 m with maximum displacement.
The heavy artillery was concentrated on the forecastle. Directly behind it - about midships - was the command tower, which at its top carried three fire control devices one above the other. The vents from all three boiler rooms were combined in a single chimney in the middle of the superstructure group. At its end was the main mast, around which two more fire control stations were arranged one above the other. The aircraft system with catapult and hangar was located on the aft ship .
drive
The drive system consisted of six boilers and four geared turbines that worked on four shafts . According to the power station or unit principle, the drive system was housed in alternating boiler and machine rooms. The front boiler room housed two boilers, behind it was the engine room with the turbines for the outer shafts. This was followed by two more boiler rooms with the four remaining boilers and finally the aft engine room with the turbines for the inner shafts.
The oil-fired narrow-tube boilers came from Indret. They worked with a steam pressure of 27 kg / cm² and a steam temperature of 350 ° C. The geared turbines were of the Parson type . The drive system was designed for an output of 107,000 shaft horsepower and a speed of 29.5 kn . In test drives, which were carried out with displacements around the normal displacement, the ships reached speeds of just over 30 kn with around 115,000 hp. By accelerating the drive system, the acceptance tests achieved outputs of over 135,000 hp and speeds of around 31 knots for two hours.
A maximum of 4,500 to 5,000 tons of fuel could be bunkered. During the war, however, only 3,700 tons should be carried in order not to impair the protective effect of the underwater protection. With this fuel supply, the range was estimated at 7,850 nautical miles at 15 kn and 2,450 nautical miles at 28 kn.
For their time, the ships had generators with a high output. Two turbo generators with 900 kW output each were installed as the main power source in each of the two engine rooms. For the power supply in the port when the ship's engines were not in use, three diesel generators with 400 kW each were used, which were located near the ship's floor between the magazines of the main artillery. Ultimately, the ships had two diesel-powered emergency power generators with an output of 100 kW each, which were set up high in the ship under the command tower.
Armament
Heavy artillery
The main armament consisted of eight cannons of 33 cm caliber with a caliber length of L / 52 (330/52 Modèle 1931). For weight reasons, it was combined in two four-winged towers on the foredeck; The four-wing towers saved around 1,700 t in weight compared to four twin towers. Two of the pipes in each tower stood close together in pairs. An advanced design feature was that it should be possible to load the guns at any barrel elevation between −5 ° and + 35 °. In practice, however, this led to loading jams with larger elevations, so that 15 ° was selected as the loading position. The rate of fire was 1.5 to 2 rounds per minute.
The guns fired an armor-piercing shell weighing 570 kg (O.Pf. Modèle 1935 - Obus de Perforation) with a muzzle velocity of 870 m / s. With a maximum tube elevation of 35 °, the range was 41.5 km.
The armor-piercing shell had a base detonator variable ignition delay of the projectile should react when hitting the target on the degree of deceleration. This should make it effective against both heavily armored and lightly armored targets. The explosive charge weighed 20.3 kg and, at 3.6% of the projectile weight, was relatively large for an armor-piercing shell. The reason could be that the projectiles were designed for the rather weakly armored armored ships of the Germany class. Later versions of the projectile (OPfK Modèle 1935 - Obus de Perforation Dispositif 'K') had a colored bag with an explosive charge under the ballistic hood, which should make it possible to assign hits and water columns to the various ships. 896 projectiles were carried, spread over 456 floors for Tower I and 440 for Tower II.
Apparently a head detonator HE shell was also developed for the gun, but not used.
Middle artillery
The middle artillery had a caliber of 13 cm and consisted of 16 tubes with a caliber length of L / 45 (130/45 Modèle 1932), arranged in three quadruple turrets aft and one double turret each on port and starboard amidships. The guns could be used against surface and air targets, which is why the maximum barrel elevation was 75 °. The guns of the middle artillery could also be loaded at every elevation. As with the main artillery, the tubes in the quadruple storms were combined in pairs.
The rate of fire was 10 to 12 rounds per minute and tube.
The guns fired unit ammunition. There were three projectile types available:
- A multi-purpose grenade (OPfK Modèle 1933) against surface targets (weight 33.4 kg, muzzle velocity 800 m / s; with paint bag)
- An explosive grenade (OEA Modèle 1934 - Obus Explosif en Acier) primarily for air defense (weight 29.5 kg, muzzle velocity 840 m / s)
- A light grenade (OEcl Modèle 1934 - Obus Eclairant) for lighting targets in night battles (weight 30 kg).
The range against ground targets was 20.8 km at 45 ° elevation, the maximum shot height against aircraft was approx. 12 km.
The magazine capacity was 6,400 rounds, of which 2,000 were multi-purpose grenades, the remainder high-explosive shells with time fuses and flares.
Light air defense
According to the design, the class was to receive five double mounts of a fully automatic 37 mm cannon under development . Since their development was delayed, the ships received the older 37 mm cannons as an interim solution in individual (model 1925) and double mounts (model 1933) in varying numbers. In this case, it was semi-automatic guns with a maximum cadence of about 30 rounds per minute and pipe (in practice 15 to 20 shots) and a correspondingly low efficacy against modern aircraft. In addition, the installation of 32 13.2 mm Hotchkiss machine guns in eight quadruple mounts was planned, these only came on board gradually.
Fire control
The ships carried seven fire control devices (central alignment devices): three on top of each other on the command tower, two on top of each other on the rear tower and one on each side of the bridge to the fire control at night.
The lower control station on the command tower was the primary control station for the heavy artillery. It was equipped with a 12-meter range finder . The control stations above were used by the middle artillery and had a 6-meter or a 5-meter device. Of these two, the upper one was an air target control station and the lower one for sea targets.
Due to their arrangement, the control rooms on the command tower offered an unrestricted field of vision and a wide view, were free from boiler smoke and were optimally protected against impacts. However, they were very heavy - the three control stations together weighed 85 tons - more than 20 meters above the waterline .
On the rear tower was the secondary control center for the main artillery with an 8-m range finder and above that another control center for the middle artillery with a 6-m range finder.
The control stations delivered the data to the artillery center housed in the citadel with the fire control computers. These in turn could aim the guns via a remote control, the first such device on a French battleship. However, the electro-hydraulic drive in the lateral direction was too weak and the synchronization between fire control unit and turret was poor.
Other rangefinders were located in the towers of the main artillery (12 m base), in the quadruple turrets of the middle artillery (6 m base) and for general observation purposes on the bridge tower.
Seven searchlights were available for night battles . Four 1 m rangefinders were installed for the 37 mm cannons.
Armor protection
In order to maximize the armor's strength, the armor was limited to the vital areas, the rest of the ship was left unprotected (so-called all-or-nothing armor). The armor protected the propulsion system and magazines in the area called the “citadel” amidships, armament and command elements as well as rudder system and shafts. The advantage of this concept was that the armor strength could be maximized for the most important areas of the ship. The disadvantage was that the long forecastle of the ships remained unprotected, so that there was a risk of strong water ingress if hit.
The weight share of the armor of the hull and armament was 36.8% of the design displacement, the highest value achieved up to then.
Armor of the citadel
The citadel formed an armored box which laterally from the side armor, above the main tank deck and front and rear of tank cross bulkheads was enclosed. She took up about 58% of the ship's length. Attempts were made to keep this as short as possible in order to save armor weight.
The side protection consisted of a 225 mm thick, approximately 5.75 m high armored belt, which tapered at the lower edge and was backed with 60 mm teak . At normal displacement , approx. 3.5 m of the belt lay above and approx. 2 m below the waterline . It was arranged inside the hull and, viewed from top to bottom, inclined inward by 11 ° 30 ′ in order to offer an inconvenient angle of incidence for shells hitting obliquely.
The main armored deck was 115 mm thick - 125 mm above the magazines of the main artillery - and lay flat on the main deck, which was made of 15 mm of shipbuilding steel. At the side it ended with the upper edges of the armored belt. One deck below was a 40 mm thick fragment trap deck with a side slope, which on the outer edge hit the lower edges of the armored belt and the raised double floor.
The front transverse bulkhead reached down from the main armored deck to the floor of the ammunition chambers and had a thickness of 210 mm (outboard of the torpedo bulkheads only 130 mm). The armored transverse bulkhead at the rear end of the citadel was 180 mm thick from the height of the main armored deck down to the height of the splinter trap deck, including only 80 mm. The transverse bulkheads were backed with 18 mm thick steel layers. The smaller thickness of the rear transverse bulkhead below the level of the fragmentation deck was considered sufficient because the protection of the drive shafts was attached at this height behind the citadel.
Various bulkheads within the citadel were reinforced as splinter protection. Between the main armored deck and the fragmentation deck there was a 20 mm thick longitudinal bulkhead that the torpedo bulkhead (see section underwater protection) continued upwards. The transverse bulkheads behind the second engine room, between the first engine room and the second boiler room, in front of and behind the magazine of 33 cm tower II and behind the magazine of 33 cm tower I were 18 mm thick. Finally, the transverse bulkheads that enclosed the citadel at the front and rear were also reinforced to 18 mm.
Protection of the drive and control elements
Behind the citadel, at the level of the fragmentation deck, a 100 mm thick armored shield with equally thick side embankments was attached, which protected the drive shafts. The last 8 m of the shield protected the steering gear; there the armor material was reinforced to 150 mm. The shield was closed at the rear by a 150 mm thick transverse plate. There was a 50 mm thick transverse bulkhead in front of the steering gear, while 20 mm thick bulkheads were located along the steering gear as splinter protection.
Protection of artillery and command elements
The barbettes of the main and middle artillery and the shaft to the command post protruded from the citadel . The following table summarizes the armor of the turrets and barbeds.
| Main artillery | MA Quadruple Storms | MA twin towers | |
|---|---|---|---|
| Front: | 330 mm | 135 mm | 20 mm |
| Pages: | 250 mm | 90 mm | 20 mm |
| Ceiling: | 150 mm | 90 mm | 20 mm |
| Back: | 345 mm (1st tower) or 335 mm (2nd tower) |
80 mm | 20 mm |
| Barbette: (above the main armored deck) |
310 mm | 120 | 3 layers of 20 mm |
| Barbette: (between the armored decks) |
50 mm | no | no |
The towers of the heavy artillery were each divided into independent halves by 40 mm thick longitudinal bulkheads. The quadruple turrets of the middle artillery had a 20 mm thick central bulkhead.
The command post was protected on five sides with armor plates 270 mm thick (front and sides) or 220 mm (rear), the roof was 130 mm to 150 mm thick. All of these armor plates were backed with two 15 mm thick plates made of normal steel. The floor of the stand was 100 mm thick.
Light armor plates protected the command tower (10 mm) and the front fire control devices (20 mm) against machine gun fire from low-flying aircraft.
Others
The boiler hoods were only weakly protected above the main armored deck by a box made of 20 mm thick plates.
The main armored belt, the armor of the command tower and the towers of the main artillery and their barbettes above the main armored deck were made of armored steel hardened on one side . The armoring of the upper sides of the main artillery and the command post was optimized in this form against attacks with aerial bombs and not primarily designed to protect against artillery shells. Before Mérs-el-Kebir, this turned out to be a disadvantage: A 381 mm shell from HMS Hood, striking at a shallow angle, splintered a 150 mm armor plate on the roof of a main gun turret of the Dunkerque and broke itself to pieces. The base of the shell penetrated the armor, while a homogeneous, softer armor plate would have deflected the projectile undamaged.
Underwater protection
In the area of the armored citadel, the ships had protection against torpedo hits integrated into the hull, which consisted of a sequence of empty and filled rooms according to the sandwich principle.
The double floor of the ships was pulled up to the lower edge of the armored belt. The outer wall of the ship ran straight down from the upper edge of the armor belt and then bent inward to meet the double bottom in the area of the notch . In this way there was a space up to 1.5 m deep between the ship's wall and the double floor or armored belt, which was filled with ebonite foam . The ebonite foam was intended to prevent water ingress in the event of underwater hits.
The fuel bunkers in the 90 cm deep, vertical part of the double floor were to remain empty during the war, so that there was an empty space behind the ebonite layer.
Behind the double floor there was a 3.9 m deep fuel bunker and a 0.7 m deep empty space. The system was completed by a 30 mm thick torpedo bulkhead. In the area of the ammunition chambers of the main and middle artillery, the torpedo bulkhead was reinforced to 40 mm to 50 mm to compensate for the shallower depth of the protection system. In addition, the fuel bunkers were shallower and the space behind them was filled with ebonite foam. To the side of the ammunition chambers of the foremost tower, the fuel bunkers were completely missing.
The bottom of the magazines of the main artillery and the aft magazines of the middle artillery were raised from the ship's floor and reinforced to 30 mm to protect against mine hits.
The maximum depth of the system at its widest point was almost 7.5 meters, which was a very high value. According to the design calculations, it should withstand torpedo warheads with a load up to 300 kg.
Aircraft facilities
A 22 m long compressed air catapult was installed on the aft deck, which could bring aircraft up to 3.5 t into the air. In front of the catapult was a two-story hangar including an elevator for two aircraft. There were up to three flying boats of the type Loire 130 provided. You should by the float - fighter Loire 210 be replaced or supplemented. This was not done because the Loire 210 was not a successful aircraft type.
In order to be able to take the seaplanes on board again after landing, a crane with a lifting capacity of 4.5 t was installed on the port side of the hangar.
The tanks with aviation fuel were also located in the stern.
Differences between the ships Dunkerque and Strasbourg
The following table summarizes the differences between the Dunkerque and the Strasbourg .
| Dunkerque | Strasbourg | |
|---|---|---|
| Displacement Standard: Normal: Maximum: |
26,500 tons l. 30,750 tons 35,500 tons |
27,300 tons l. 31,570 tons 36,380 tons |
| Length ü. A .: | 215.14 m | 215.50 m |
| Draft (max.): | 9.71 m | 9.89 m |
| Armored belt: | 225 mm 11 ° 30 ′ inclination |
283 mm 11 ° 50 ′ inclination |
| Front transverse bulkhead: | 210 mm | 228 mm |
| Aft transverse bulkhead: | 180 mm | 210 mm |
| Main artillery Tower front: Tower ceiling Back side: Upper barbette |
330 mm 150 mm 345 mm or 335 mm 310 mm |
360 mm 160 mm 352 mm or 342 mm 340 mm |
| Armored deck embankment: | 40 mm | 50 mm |
| Speed: | 31.06 kn | 30.36 kn |
| Headlights: | 7 × 1.2 m | 6 × 1.2 m |
Outwardly, the two ships differed mainly in the bridge structure. The Strasbourg had another enclosed deck in the front area of the bridge, and the gallery was further up on the tower structure.
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Comparison of the bridge structures in Dunkirk (left) and Strasbourg (right)
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Conversions
Both ships underwent only minor modifications during their lifespan. Most of these concerned the completion and regrouping of the light anti-aircraft guns .
Both ships received larger chimney attachments in 1938.
At the Dunkerque , the rangefinder of the main fire control station at the front was exchanged for a 14 m model in early 1940. At the beginning of 1942, Strasbourg received a radar device made in France, with the ME-140 transmitter and MR-126 receiver units from Sadir being installed in front of the bridge structure. They covered about 45 ° and should be able to locate targets up to 50 km away.
Evaluation of the draft in the literature
The design of the Dunkerque- class deviated radically from the previous design practice of the French Navy and exhibited a number of advanced features:
- armoring according to the "all or nothing principle"
- modern underwater protection
- a weight-efficient drive system with high pressure tanks and light geared turbines
- a medium artillery set up in turrets and - a novelty - air-defensive artillery
- a purpose-designed aircraft system, the first one planned from the start on a battleship.
As completely new designs, the ships had a number of weaknesses. Some of these weaknesses were teething troubles that would probably have been correctable with longer active service.
The slim shape of the hull at the front in connection with the low freeboard restricted the seaworthiness of the ships, and in bad weather the speed had to be reduced. The lightly built bow was prone to sea damage, as was evident at the start of the war in the North Atlantic and Biscay.
Although the principle of the underwater protection was well designed, the battle damage at Mers-el-Kébir and the subsequent repairs revealed some weak points. The cable ducts turned out to be insufficiently watertight, which called into question the value of the entire system. In addition, the cable material was easily inflammable. The ebonite foam was also flammable if it absorbed leaking fuel.
The quadruple storms of both the heavy and medium artillery were prone to failure, the remote control never worked properly. The target tracking speed of the middle artillery was too slow for air targets.
The scattering of heavy artillery was great. The reason was probably the fact that the gun barrels were too close together in pairs (barrel spacing 1.69 m). This led to the fact that when a half-volley was fired through one half of the tower, the trajectories of the grenades were disturbed by the pressure wave of the other tube.
Jordan and Dumas estimate based on German information that the belt armor of the Dunkerque would have been immune to the 28 cm guns of the Scharnhorst class at distances of over 20 km, the thick belt armor of the Strasbourg at distances of more than 15 km . The authors assume that the penetration performance of the German grenades is assessed optimistically. The deck armor would presumably have been immune to all combat distances. The German ships, on the other hand, had thicker belt armor, but their communications and electrical equipment were largely only poorly protected over the armored deck.
Compared to 38 cm guns, the armor protection was completely inadequate, as was shown in the naval battle of Mers-el-Kébir . However, it was not designed for this either. The British fleet was not considered an opponent at the time of design, while the Richelieu class was to be used against the ships of the German Bismarck class and the Italian Littorio class .
Career
| Shipyard | Keel laying | Launch | Completion (Clôture de l'armement) |
fate | |
|---|---|---|---|---|---|
| Dunkerque : | Arsenal de Brest | December 24, 1932 | October 2, 1935 | June 9, 1938 |
sunk on November 27, 1942, wreck abandoned after the war |
| Strasbourg : | Ateliers & Chantiers de Saint-Nazaire | November 25, 1934 | December 12, 1936 | April 6, 1939 | sunk on November 27, 1942, wreck abandoned after the war |
Both ships were assigned to the Atlantic fleet after the commissioning. When the war broke out, the ships joined the so-called Force de Raid. This unit, consisting of ultra-modern ships, was supposed to protect the Allied trade routes and hunt down German trade troublemakers. In addition to the two battleships, three light cruisers of the La Galissonnière class and the six large destroyers of the Le Fantasque class belonged to the Force de Raid. The battleships did not normally operate together, but in cooperation with British units.
In April 1940, the ships were moved to the Mediterranean and stationed in Mers-el-Kébir . A planned mission off Norway did not materialize, the ships remained in the Mediterranean due to Italy's imminent entry into the war.
Both ships were in port during the British attack on Mers-el-Kébir on July 3, 1940. The Strasbourg escaped to Toulon , but the Dunkerque was badly damaged and suffered losses of over 200 men. After repairs on site, she moved to Toulon on February 19, 1942. There both ships were sunk by their crews on November 27, 1942 when German troops marched in . In consultation with the German government, the Italian Navy salvaged both ships. Repairs were considered too costly, which is why they should be scrapped. The Strasbourg was sunk again by American bombers on August 18, 1944. The Hulks were finally deleted in 1955 and sold for demolition.
Remarks
- ^ According to Breyer: Battleships and battle cruisers , p. 441: 1,381 peace strength, 1,431 war strength.
- ^ According to Breyer: Battleships and battle cruisers , p. 459, Dunkerque received geared turbines of the Rateau type.
- ↑ Light armor plates delayed the projectile weakly, which should result in a shorter ignition delay than the stronger deceleration of the projectile by heavy armor plates.
- ↑ Compare the corresponding weight percentages of the armor in the ships of the Nelson class with 34% and the King George V class with 40%, which were also built under contract conditions . Numbers according to Breyer: Battleships and battle cruisers 1905–1970 , pp. 197, 201, 459.
- ↑ In front of this magazine was the front tank bulkhead of the citadel.
- ↑ According to Jordan, Dumas: French Battleships 1922–1956 , p. 47. Breyer: Battleships and battle cruisers 1905–1970 , p. 459 gives a maximum depth of 7 m, which also corresponds to the addition of the individual values in Jordan, Dumas.
- ↑ Whereby the relevant information in Jordan, Dumas: French Battleships 1922–1956 , p. 51 f. contradicting each other, there is talk of 3.5 t and 3.3 t.
- ↑ The four-of-a-kind turrets of the battleships of the Richelieu class, which had the same structure, suffered from the same problem. This was remedied in 1948 by adding thyratrons to the ignition circuitry, which delayed the firing of the outer tubes by 60 milliseconds.
Individual evidence
- ↑ z. B. Jane's Battleships of the 20th Century. Harper Collins Publishers, London 1996, ISBN 0-004-70997-7 .
- ↑ Unless otherwise stated, the information in this article comes from: Jordan, Dumas: French Battleships 1922–1956.
- ↑ David and Hugh Lyon; Siegfried Greiner: Warships from 1900 to today, technology and use . Buch und Zeit Verlagsgesellschaft mbH, Cologne 1979, p. 81 .
- ^ A b John Jordan: Warships after Washington. Seaforth Publishing, Barnsley 2011, ISBN 978-1-84832-117-5 , pp. 103 f.
- ^ Whitley: Battleships , p. 74.
- ↑ Breyer: Battleships and battle cruisers , p. 314.
- ↑ Erminio Bagnasco, Augusto de Toro: The Littorio Class. Seaforth Publishing, Barnsley 2011, ISBN 978-1-84832-105-2 , p. 12 ff.
- ↑ Jordan, Dumas: French Battleships 1922-1956 , p. 50.
- ↑ a b c Whitley: Battleships , pp. 45ff.
- ↑ a b c d e Breyer: Battleships and battle cruisers , p. 457ff.
- ^ Robert Dumas: Les cuirassés Dunkerque et Strasbourg. under Installations Des Chambres de Distribution Et Des Soutes .
- ^ John Jordan, Jean Moulin: French Cruisers 1922-1956 . Seaforth Publishing, Barnsley 2013, ISBN 978-1-84832-133-5 , p. 19.
- ^ Jane's Battleships of the 20th Century. Harper Collins Publishers, London 1996, ISBN 0-004-70997-7 , p. 22.
- ^ Nathan Okun: Table of metallurgical properties of naval armor and construction materials on combinedfleet.com, accessed September 30, 2013 .
- ↑ except Jordan, Dumas see also Breyer: Battleships and battle cruisers 1905-1970 , p. 459.
- ^ Contemporary assessment by Admiral de Laborde, reproduced in Jordan, Dumas: French Battleships 1922–1956 , p. 226.
literature
- Siegfried Breyer: Battleships and battle cruisers 1905–1970. JF Lehmanns Verlagsgesellschaft mbH, Munich 1970, ISBN 3-88199-474-2 .
- Robert Dumas: Les cuirassés Dunkerque et Strasbourg. Marines Editions et Réalisations, Bourg-en-Bresse 1993.
- John Jordan, Robert Dumas: French Battleships 1922–1956. Corrected reprint. Seaforth Publishing, Barnsley 2010, ISBN 978-1-84832-034-5 .
- Mike J. Whitley: Battleships of World War Two. Cassel & Co, London 2001, ISBN 0-304-35957-2 .
- Technical information on www.navweaps.com for main armament and middle artillery .
