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 DCNs 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. 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. "The Agosta 90B submarine is fitted with four bow 533mm torpedo
tubes and can carry up to 16 torpedoes and missiles." 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.
