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Le Triomphant SNLE

The SNLE-NG (Sous-marin Nucléaire Lanceurs d'Engins-Nouvelle Génération) replaced the Redoutable submarine 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 was 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 equiped the first three SNLE-NGs when they became operational. The fourth was to 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. As of 2000, Le Vigilant had been set to be equiped with the M45 missile.

Terrible, operational since 2010, was the first to have the new M-5 intercontinental ballistic missile, whose range is given at 9000 kilometers. The first three SSBNs of the series, Triumphant, Bold and Vigilant respectively delivered in 1997, 1999 and 2004, had then the M45 can implement, each up to six TN 75 of 110 kilotonnes heads. These submarines are amortized to standards Terrible as part of a major overhaul completed in 2013 on The Vigilant and must be completed in late 2015 for Triumphant. This will be the turn of Bold to be modernized to a return planned fleet by 2018.

Le Terrible, the fourth Le Triomphant-class SSBN, was ordered on 28 July 2000 with a planned service date of 2008, eventually delayed to 2010. Le Terrible entered service in September 2010, at the same time as the new M51 strategic missile. The first to be equipped with this new generation SLBM, Le Terrible carries 16 M51 missiles. Plans called for the other three Le Triomphant-class SNLE to be progressibely backfitted to accomodate the M51 between 2010 and 2018.

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 win 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 [ie repairs], than every seven years (instead of five years before).

According to the CEO of DCNS, Patrick Boissier, the modernization of the Vigilant was completed in July 2013. "We completed in July 2013 a major and complex operation for the modernization of vigilant, with the submarine's adaptation to the new M51 missile and implementing a new combat management system. It is now the turn of the Triumphant to have the same IPER adaptation ", he told the members of the defense Committee in mid-April 2013.

"The Vigilant after which resumed its operational patrols in the summer of 2013, the SSBN The Triumphant is being adapted to Brest and resume patrols in 2016, when the operational commissioning of the M51.2 on the SSBN Le Téméraire will be adapted to M51 in the period from 2016 to 2018, by the plan of the Chief of Staff" confirmed Alain Charmeau. "It is expected shortly delivery of the third and last batch of M51 missiles and commissioning of a new version of the M51 (the M51.2) in order to equip the new missile warheads" he said.



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