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Redoutable-class submarine (1931)
Sous marin Ajax.jpg
Class overview
Name: Redoutable
Operators:  French Navy
Subclasses: Redoutable
Completed: 31
General characteristics
Type: Submarine
Displacement: 1,500 tonnes (1,476 long tons) (surfaced)
2,000 tonnes (1,968 long tons) (submerged)
Length: 92.3 m (302 ft 10 in)
Beam: 8.2 m (26 ft 11 in)
Draught: 4.9 m (16 ft 1 in)
Propulsion: 2 × diesel engines, 4,300 hp (3,207 kW)
2 × electric motors, 1,200 hp (895 kW)
Speed: 17 knots (31 km/h; 20 mph) (surfaced)
10 knots (19 km/h; 12 mph) (submerged)
Range: 14,000 nautical miles (26,000 km) at 7 knots (13 km/h)
10,000 nautical miles (20,000 km) at 10 knots (20 km/h)
4,000 nautical miles (7,000 km) at 17 knots (31 km/h)
90 nautical miles (170 km) at 7 knots (submerged)
Test depth: 80 m (260 ft)
Complement: 5 officers (6 in operations)
79 men
  • 9 × 550 mm (21.7 in) torpedo tubes
  • 2 × 400 mm (15.7 in) torpedo tubes
  • 1 × 100 mm (4 in) deck gun
  • 2 × 13.2 mm (1 in) machine guns

The Redoutable class submarines were ocean-going submarines of the French Navy during the Second World War. They were officially called "Long patrol submarines" (Fr:Sous-marins de grande patrouille), or "Type 1 submarines".[1][2] They were also referred to as the 1500 Series, and regarded as being in three sub-classes[3][4] (Though French Navy recognize only two[5]) The Redoubtable class were generally regarded as successful, being reliable and seaworthy, with a good range and armament. A total of 31 were built, the largest class of submarines built by the French Navy, and comprising one-third of its total submarine force.


The Redoutable class were built for service in the Atlantic, operating as scouts, or as commerce raiders, and for colonial service. They were built to conform to the interwar naval treaties arising from the 1922 Washington and 1930 London conferences, which placed restrictions on the number and size of warships of various types that nations could build.[6] The Redoutable class were designed and built as successors to the Requin class, France's first post-war Type 1 design. Orders were placed in 1924 for the first two boats, Redoutable and Vengeur, followed by orders for seven more (1925), then five (1926), and a further five (1927). In 1929 a further order was placed for six boats of an improved design with more powerful engines, followed in 1930 by another six, again with improved engines and speed.[7]

General characteristics

Arrangement plan of a French 1500 ton class submarine.

The 1500s were built to a 92 metre double-hulled design, with an emphasis on surface speed and a long range. They had a surface displacement just above 1,500 tons, the upper limit by treaty. They were rated for a dive depth of 80 metres, though in service depths of 120 metres were recorded.[8] Diving time was 30 to 40 seconds, and their underwater range was 100 miles at 5 knots. Surface range was 10,000 miles at 10 knots, with a maximum of 19 to 20 knots, and a maximum submerged speed of 10 knots. Their armament was eleven torpedo tubes (4 forward, 3 midships, and 3-4 aft) with an outfit of 13 torpedoes. As with other French submarines of this period, the 1500s had torpedo tubes fitted externally in trainable mounts; in this case they were midships and astern. The stern mount also had tubes of two different sizes, for different targets. They had a single 3.9 inch/100mm gun, and one to two 13.2mm machine guns. and were manned by crews of 61 men.[9][10]

One drawback suffered by these vessels was their engines, which, though reliable, were noisy, both diesel and electric, a disadvantage when operating with stealth. They were also criticized for their habitability, with inadequate ventilation and storage for foodstuffs.

In 1943 the five boats still in service were refitted in the USA. A second anti-aircraft gun was added, on a platform ahead of the conning tower, and the torpedo armament was rationalized; the two 400mm tubes were removed from the stern mount and replaced by a single 550 mm tube.[11]


Built over ten years by a number of different shipyards, the 1500s differed in details of design and construction. The first two (Redoutable and Vengeur) were equipped with a generator for recharging the batteries for the electric motors; the following vessels all dispensed with this, recharging directly from the diesel engines. Nine vessels (Achille, Ajax, Archimede, Argo;, Le Centaure, Pasteur, Persee, Poncelet and Promethee), were equipped with Schneider diesels, the remainder with engines by Sulzer. There was also a progressive increase in motive power; the boats of the 1922 programme, (Redoutable and Vengeur) had engines rated at 4000 rpm (cite needed) those of the 1925, 1926 and 1927 programmes 6,000 hp. In the 1929 programme this was increased to 7,200 hp, and in the 1931 boats 8,600 hp. This in turn led to a progressive improvement in surface speed; the first series made 17 knots on the surface, the 1929 boats 19 knots, and the 1930 boats 20 knots. These differences form the basis of the class division into sub-classes. A number of sources[12][13][14] make a three part division; the boats of the 1922, 1925, 1926 and 1927 programmes in the first series; those of the 1929 programme the second sub-class, or series, and the 1930 boats the third. Those sources that make a two class division regard Redoutable and Vengeur as one sub-class, (referred to as project M5) and the remaining 29 (project M6) as the other.[15][16]

War service

The Redoutable class served with the Marine Nationale and with Vichy and Free French forces during World War II in a full range of front-line duties and missions. Of the 29 boats that served in World War II (two were lost in the pre-war period), 24 were lost.

At the outbreak of war there were 29 vessels of the 1500 class; two had been lost accidentally in the 1930s. At the Fall of France four boats undergoing repair at Brest (Pasteur, Achille, Agosta and Ouessant) were scuttled; another (Protée) was interned at Alexandria. The remaining 1500’s were with the French fleet, or at various overseas stations.

Five were lost in the months after the armistice; Three (Persee, Ajax and Poncelet) were sunk in the attack on Dakar, another (Sfax) was sunk in error by the German U-37, and Pegasee was decommissioned at Saigon in French Indochina.

In May 1942 three more (Bevezier, L'Héros and Monge) were sunk when Madagascar came under attack; in November another three (Actéon, Le Conquérant and Sidi Ferruch) were sunk resisting the Allied invasion of North Africa and a fourth (Le Tonnant) was scuttled. At the end of November, when the Germans occupied Vichy France, seven boats were scuttled at Toulon. The remaining five (Argo, Archimède, Le Centaure, Le Glorieux and Casabianca) still in French hands when she rejoined the Allies all survived until the end of the war, being decommissioned in 1952.[17][18]

Ships in class

First series

Name Pennant
Ordered Builder Commissioned Fate
Redoutable Q136 1924 Arsenal de Cherbourg 24 February 1928 scuttled, Toulon: raised, destroyed in air raid 1944
Vengeur Q137 1924 Arsenal de Cherbourg 1 September 1928 scuttled, Toulon, 27 November 1942
Archimède Q142 1925 CNF, Caen 6 September 1930 survived the war; BU 1952
Fresnel Q143 1925 AC St Nazaire-Penhoet 8 June 1929 scuttled, Toulon: raised, destroyed in air raid 1944
Henri Poincaré Q140 1925 Arsenal de Lorient 10 April 1929 scuttled, 9 September 1943
Monge Q144 1925 FC Mediterranee, La Seyne 25 June 1929 sunk, 8 May 1942
Pascal Q138 1925 Arsenal de Brest 19 July 1928 scuttled, Toulon: raised, destroyed in air raid 1944
Pasteur Q139 1925 Arsenal de Brest 19 July 1928 scuttled, Brest, 18 June 1940
Poncelet Q141 1925 Arsenal de Lorient 10 April 1929 scuttled, 18 November 1940
Achille Q147 1926 Arsenal de Brest 28 May 1930 scuttled, Brest, 18 June 1940
Ajax Q148 1926 Arsenal de Brest 28 May 1930 sunk by HMS Fortune, 24 September 1940 during Battle of Dakar
Actéon Q149 1926 AC Loire, Nantes 10 April 1929 sunk, 8 November 1942
Achéron Q150 1926 AC Loire, Nantes 6 August 1929 scuttled, Toulon, 27 November 1942: raised, destroyed in air raid 1943
Argo Q151 1926 AC Dubigeon, Nantes 11 April 1929 survived the war, BU 1946
Protée Q155 1927 FC Med. La Seyne 31 July 1930 sunk 29 December 1943 by Axis patrol boats
Pégase Q156 1927 AC Loire, Nantes 28 July 1930 de-commissioned, Saigon, 1941 /BU 1950
Persée Q154 1927 CNF 23 May 1931 sunk, 23 September 1940
Phénix Q157 1927 AC Dubigeon 12 April 1930 accidental loss. 15 June 1939
Prométhée Q153 1927 Arsenal de Cherbourg 1930 accidental loss, 8 July 1932

Second series

Name Pennant
Ordered Builder Commissioned Fate
L'Espoir Q167 1929 Arsenal de Cherbourg 18 July 1931 scuttled, Toulon, 27 November 1942
Le Glorieux Q168 1929 AC St Nazaire-Penhoet 29 November 1931 survived the war, BU 1952
Le Centaure Q169 1929 Arsenal de Brest 14 October 1932 survived the war, BU 1952
Le Héros Q170 1929 Arsenal de Brest 14 October 1932 sunk, 7 May 1942
Le Conquérant Q171 1929 AC Loire, Nantes 26 June 1934 sunk, 13 November 1942
Le Tonnant Q172 1929 FC Mediterranee, La Seyne 15 December 1934 scuttled, Cadiz, 15 November 1942

Third series

Name Pennant
Ordered Builder Commissioned Fate
Agosta Q178 1930 Arsenal de Cherbourg 30 April 1934 scuttled, Brest, 18 June 1940
Sfax Q182 1930 ACL, Nantes 6 December 1934 torpedoed by U-37, 19 December 1940
Casabianca Q183 1930 ACL Nantes 2 February 1935 survived the war. BU 1952
Bévéziers Q179 1930 Arsenal de Cherbourg 14 October 1935 sunk, 5 May 1942
Ouessant Q140 1930 Arsenal de Cherbourg 30 November 1936 scuttled, Brest, 18 June 1940
Sidi Ferruch Q181 1930 Arsenal de Cherbourg 9 July 1937 sunk, 11 November 1942

See also


  1. Conway p274
  2. Type 1's were oceanic submarines; type 2's were coastal submarines; and type 3's were mine layers
  3. Conway p273
  4. Bagnasco p38
  5. Huan p
  6. Bagnasco p38
  7. Bagnasco p38
  8. Aboukir p
  9. Bagnasco p46
  10. Conway p273
  11. Bagnasco p46
  12. Bagnasco p46
  13. Conway p273
  14. Miller p
  15. Huan p
  16. Picard p
  17. Bagnasco p46
  18. conway p274


  • Bagnasco, E :Submarines of World War Two (1977) ISBN 0-85368-331-X
  • Conway : Conways All the Worlds Fighting Ships 1922-1946 (1980) ISBN 0-85177-146-7
  • Claude Huan, Les Sous-marins français 1918-1945, Rennes, Marines Éditions, 2004, 240 p.
  • Claude Picard, Les Sous-marins de 1500 tonnes, Rennes, Marines Editions, 2006, 119 p.
  • Miller, D : Submarines of the World (1991) ISBN 0-86101-562-2

External links

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