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Le Triomphant SNLE

The SNLE-NG (Sous-Marins Nucleaires Lanceurs Engins-Nouvelle Generation) will replace the Redoutable class. The class was originally planned to include six boats. Later versions were possibly to have been longer, up to 170 meters, versus the 138 meters of the initial boats. The strategic submarine program was reduced to three for budgetary reasons, but President Chirac decided that the SNLE-NG programme would produce four submarines. On 23 February 1996 the announcement by the President of France on the new format for French nuclear forces called for scaling down of ballistic missile nuclear submarine force from five to four. Constructing the fourth SNLE cost 13 billion francs, and avoided a drawdown in deployments. Of the submarines currently in the strategic submarine force (FOST), four are always operational and two are at sea. With four SNLEs, three could be operational at any given time. The SNLE-NG program is estimated to cost 88.4 billion francs for four submarines. The average cost per submarine has increased from 10 billion francs in 1986 to 12.5 billion.

The first of the class was ordered 10 March 1986 with building decision taken 18 June 1987. The second was ordered on 18 October 1989; the third was delayed until 27 May 1993. Sea trials of Le Triomphant started in early 1994, and the boat was commissioned on 21 March 1997. Le Téméraire, the second in the series of new SNLE-NG generation of missile-launching nuclear submarines, was commissioned into active service on 23 December 1999, after successfully passing its sea trials. The ship is now operational in the Oceanic Force.

As of 1996 the schedule for the third, Le Vigilant, had slipped until 2001 and the service date for the fourth SSBN was approximately 2005. The admission with the active service of Vigilant, ordered in May 1993, was delayed, first by six months, and a second time in 1996 by two years. In the 1998 budget the Vigilant was delayed one year, which involved the corresponding prolongation of a SNLE in service. It will enter active service in July 2004 (a four and a half year delay). Construction of the third unit, Le Vigilant, continued in 1999. This submarine should be commissioned in 2004. The order for the fourth unit, planned initially for 1996 was deferred into 2000 for an admission to the active service in July 2008 (four years and eight month of delay), requiring the maintenance in service of l’Inflexible until that time. SNLE NG n°4 was finally ordered by the Commission de la défense de l’Assemblée nationale on 15 September 1999.

The upgraded M45 missile will equip the first three SNLE-NGs when they become operational. The fourth will receive a new model missile, the M51. The M-5 missile development was first funded in the 1988 budget and the program was accelerated to start in 1993, which was earlier than inially planned. Le Vigilant was intended to be the first to commission with M-5, the others being back fitted. But as of 2000 Le Vigilant will be equiped with the M 45 missile.

To remain acoustically furtive, with respect to the new means of detection, the objective attached to the design of the submarines was to gain in this field, a factor 1000 compared to the submarines of the type "Le Redoutable M4 ". During the design of the Le Triomphant, studies were carried out in order to limit the sound sources and the vibrations of many elements, as well on the level of the hull and the engine as to that of the 750,000 embarked apparatuses and the 50 km pipings conveying the fluids on board.

While moving the hull of a submarine creates in the water flows which can be noisy. Also, very particular care was taken with the hydrodynamics of the hull and the appendices (work completed by the basin of test of the hulls). Each part was studied to limit turbulences. The external bridge, made out of composite materials by DCN Lorient to avoid, in particular, with the submarine resounding like a " skin of drum ".

The pusher propeller is also a significant source of disturbance of the marine medium, in particular because of cavitation, a phenomenon which releases from the bubbles of air crépitantes at the end of the blades. The standard SNLE Le Triomphant, for this reason, was equipped with a ducted propeller, called " propeller pump " developed by the basin of tests of the hulls and produced by DCN Indret and DCN Cherbourg.

To limit the vibrations of the revolving machinery, the ball bearings which tend to hum were replaced by smooth stages , certainly more difficult to adjust with manufacture, but infinitely less noisy and more stable in the long run.

To ensure that inevitable noises are not propagated outside the hull, the rigid connections which connect the noisy hardware with the hull were defined to damp out all the vibrations. The rigid connections were replaced by kinds of cradles connected to the hull via suspensions filtering the vibrations. On these cradles, each engine, each pipe, each electric cable is in its turn suspended or posed on other suspensions filtering noises and vibrations. The noisy machines are covered with insulating caps. As for the crew, it will have to be compelled with simple rules by avoiding any inopportune din.

The profits in acoustic discretion are done initially with the design then, throughout construction, by a constant care taken to the realization of the systems of insulation of the apparatuses and pipings.

The discretion of a submarine depends, also, of the depth which it can reach, because the layers of cold water depths keep the captive sounds. Thanks to its hull, carried out in a special steel, 100 HLES (high weldable elastic limit -- HY 130 to US Standards), supporting a constraint of 100 kilograms per square millimetre, developed by CREUSOT the LOIRE INDUSTRY and DCN Cherbourg, its performances in diving is greatly increased.

The power of its new integrated nuclear reactor room, built by TECHNICATOME and DCN Indret, as well as the effectiveness of its pump propeller, confers high quiet speeds.

To gain the " war of silence ", it is not enough to do little noise. It is also necessary " to hear before being heard ". The Le Triomphant, for this purpose, is equipped with a sonar more powerful than those of the present generation, provided by THOMSON. On its hull, were laid out various antennas and chains of sensors. In operation, it trails behind him an immense chain of hydrophone sensitive to all the ranges of acoustic waves. The whole of the data, thus collected by these sensors, is analyzed and exploited on board by powerful computers, federated within the tactical operating system, whose DCN INGENIERIE ensured the control of work. But, in fine, it is also with the " gold ears ", i.e. ultimately to men specialists in underwater acoustics, which returns the care to recognize the " sound signatures " of the potential adversaries.

The requirement for the submarine to know, at any moment, its exact position is essential for the precision of firing of its missiles. With the origin and before their recasting, it was necessary to the SNLE of the old generation to return in the vicinity of surface, with regular intervals, to readjust their equipment of navigation on the stars, the satellites, or the radioelectric signals of station to ground. Today, with the development, by the SAGEM (Company of general applications of electricity and mechanics), of a very sophisticated inertial power station, it is not necessary any more. One " more " for discretion. The same company provides the periscopes and the autopilot.

The qualities of the system of combat of the submarine and very thorough automation made it possible to reduce the crew from 130 to 111 men, but more especially to increase the reliability of the vehicle by giving again with the man his place: that of that which monitors the machine. The quality and the endurance of the embarked hardware were improved, so that the submarine will not be immobilized any more, for the great careenages, than every seven years (instead of five years before).


Displacement, tons
  • 12640 surfaced;
  • 14335 dived
  • LENGTH 453 feet (138 meters)
    BEAM 41 feet (12.5 meters)
    55.8 feet (17 meters) aft planes
    DRAFT 41 feet (12.5 meters)
    Main machinery
  • Nuclear; turbo-electric; 1 PWR Type K15 (enlarged CAS 48); 150 MW;
  • 2 turbo-alternators; 1 motor; 41500 hp(m) (30.5 MW);
  • diesel-electric auxiliary propulsion;
  • 2 SEMT-Pielstick 8 PA4 V 200 SM diesels; 900 kW;
  • 1 emergency motor;
  • 1 shaft; pump jet propulsor
  • Speed, knots 25 dived
    Complement 111 (15 officers) (2 crews)
    Missiles SLBM: 16 Aerospatiale M45/TN 71; three stage solid fuel rockets; inertial guidance to 5300 km (2860 nm); thermonuclear warhead with 6 MRV each of 150 kT. (To be replaced by M5/TN 75 which has a planned range of 11000 km (6000 nm) and 10-12 MRVs).
    SSM Aerospatiale SM 39 Exocet; launched from 21 in (533 mm) torpedo tubes; inertial cruise; active radar homing to 50 km (27 nm) at 0.9 Mach; warhead 165 kg.
    Torpedoes 4 - 21 in (533 mm) tubes.
  • ECAN L5 Mod 3; dual purpose; active/passive homing to 9.5 km (5.1 nm) at 35 kts; warhead 150 kg; depth to 550 m (1800 ft);
  • total of 18 torpedoes and SSM carried in a mixed load.
  • Countermeasures ESM: Thomson-CSF ARUR 13/DR 3000U; intercept.
    Weapons control
  • SAD (Systeme d'Armes de Dissuasion) data system (for SLBMs);
  • SAT (Systeme d'Armes Tactique) and
  • DLA 4A weapon control system (for SSM and torpedoes).
  • Radars Search: Dassault; I band.
  • Thomson Sintra DMUX 80 `multi-function' passive bow and flank arrays.
  • DUUX 5; passive ranging and intercept; low frequency.
  • DSUV 61; towed array.
  • Boat List

    Boat Name Builder Ordered Laid Down Launched Commissioned Decommissioned
    S-616 Le Triomphant Cherbourg 18 June 1987 9 June 1989 13 July 1993 21 Mar 1997
    S-617 Le Temeraire Cherbourg 18 Oct 1989 1994 1996 23 Dec 1999
    S-618 Le Vigilant Cherbourg 27 May 1993 July 2004
    S-619 N° 4 Cherbourg 2000 July 2008
    S-620 Cherbourg CANCELLED
    S-621 Cherbourg CANCELLED

    Sources and Resources

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