August 2, 2013

Pakistan's three Agosta 90B (Khalid Class) submarines

Agosta 90B Class submarine

An Agosta 90B. Pakistan's three Agosta 90B's (of the Khalid Class) are the most modern and effective units in its submarine arm.

  • Crew 36 men + 5 officers + Navy "Seals" frogmen?
  • Length 67.6m
  • Draught 5.4m
  • Surface Displacement 1,510t
  • Submerged Displacement 1,760t or 2,050t with AIP MESMA plug added.
  • Maximum Speed Over 17kt
  • Range 10,000nm

  • Photo and article courtesy of

    The Agosta submarines designed by DCN (now DCNS) of France, are currently in service with the French, Spanish and Pakistan navies. The Agosta 90B is an improved version featuring higher performance and a new combat system.

    The new submarine features a higher level of automation, which has resulted in the ship's crew being reduced from 54 to 36. Other improvements include a new battery for increased range, a deeper diving capability of 350m resulting from the use of new materials including HLES 80 steel, and a reduced acoustic signature through the installation of new suspension and isolation systems.

    Agosta Class submarine orders and deliveries

    Three Agosta 90Bs were ordered by the Pakistan Navy in September 1994. The first, Khalid (S137), was built at DCN’s Cherbourg yard and was commissioned in 1999. The second, Saad, assembled at Karachi Naval Dockyard, was launched in August 2002 and was commissioned in December 2003. The third, Hamza, was constructed and assembled in Karachi, launched in August 2006 and commissioned in September 2008.

    "The Agosta 90B is an improved version of the Agosta submarine, featuring higher performance and a new combat system."
    Work on the Hamza was halted for a time following a terrorist attack in May 2002, which killed 11 French engineers in Karachi. The third submarine was fitted with the MESMA air-independent propulsion system. The MESMA AIP successfully completed Pakistan Navy acceptance trials. In March 2007, Pakistan placed an order with DCNS for the retrofit of the MESMA AIP to the first two Khalid Class submarines, whcih were delivered in December 2011.

    Pakistan has been given a license by DCNS to offer commercial production of the submarines to potential customers.

    SUBTICS command and control system 

    The Agosta 90B submarines are equipped with a SUBTICS fully integrated combat system. This is supplied by UDS International, a joint subsidiary of DCN International and Thales, now wholly owned by DCNS. SUBTICS processes signals from the submarine's sensors, determines the tactical situation by track association, fusion, synthesis, trajectory plotting and management and handles all weapon command and control functions.


    The Agosta 90B submarine is fitted with four bow 533mm torpedo tubes and has the capacity to carry a mixed load of up to 16 torpedoes and missiles. The submarine can be equipped with the ECAN F17 mod 2 torpedo, which is a wire-guided torpedo with active and passive homing to a range of 20km. The torpedo delivers a 250kg warhead to a depth of 600m.

    Exocet missiles

    The Agosta 90B is equipped with the torpedo tube launched MBDA (formerly EADS Aerospatiale) Exocet SM39 missile. Target range and bearing data is downloaded into the Exocet's computer.
    The missile approaches the target area in sea-skimming mode using inertial navigation and then active radar homing. The missile travels at speeds over Mach 0.9, and has a range of 50km. Exocet has a 165kg high-explosive shaped-charge warhead. [it is not inconceivable that some of the Exocet warheads might be nuclear - for land attack].

    Electronic warfare

    The Agosta 90B submarines are equipped with the Thales DR-3000U radar warning receiver, operating in D to K bands. The system uses a masthead antenna array with omnidirectional and monopulse directional antennae and a separate periscope warning antenna.

    Sensor suite

    The submarine is fitted with a Thales Underwater Systems (formerly Thomson Marconi Sonar) TSM 223 sonar suite, which includes bow-mounted sonar and towed sonar arrays, SAGEM periscopes and navigation system and Thales I-band navigation radar.

    Propulsion systems

    The Agosta 90B class submarines can be equipped with a diesel-electric propulsion system [and] the MESMA air-independent propulsion system. The diesel-electric system consists of two SEMT-Pielstick 16 PA4 V 185 VG diesels providing 3,600hp and a 2,200kW electric motor driving a single propeller.

    A diesel-electrical submarine has to surface to periscope-snorkel depth to recharge the batteries using the diesel engine, leading to increased risk of detection.

    The MESMA air-independent propulsion system, being fitted to the Agosta 90B submarines for Pakistan, allows the submarine to remain submerged three times longer (three weeks is the popular estimate).  The MESMA system consists essentially of a turbine receiving high-pressure steam from a combustion chamber, burning a gaseous mixture of ethanol and liquid oxygen. The Agosta 90B's performance remains the same in all other respects, except that with the 9m long MESMA "plug" added the length increases from 67m to 76m and submerged displacement from 1,760t to 2,050t."


    jbmoore said...

    Great for sneaking commandos and terrorists onto Indian beaches and coastal areas. Guess that's where all of our billions of dollars in aid went as well in personal bank accounts.

    Pete said...

    Hi JB

    I hope Khalid sub release of swimmers is just a wartime activity.

    Reconnaissance and electronic intercept of land, ship and "enemy" sub signals might be Khalid's peacetime routine activities.