Navy Agosta-90b submarine (Pakistan)

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.


In March 2007, Pakistan placed an order with DCNS for the retrofit of the MESMA AIP to the first two Khalid Class submarines. The retrofit kits will be delivered to the Karachi dockyard in 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.

Torpedoes

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.
MBDA Exocet SM39 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.
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 or 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 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.

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 the length increases from 67m to 76m and submerged displacement from 1,760t to 2,050t.