OVERVIEW: The S 137 *Khalid* [Agosta 90B] is a diesel-electric attack submarine operated by the Pakistan Navy. The vessel represents a significant upgrade over the earlier Agosta 70 design, incorporating improved sensors, weapons, and stealth characteristics.

DETAILS: The Agosta 90B program originated from the French desire to modernize its diesel-electric submarine fleet and offer a competitive design on the international market. The design prioritizes acoustic discretion, utilizing advanced hull coatings and a resiliently mounted machinery raft to minimize noise signature. This focus on stealth, combined with improved sensor performance, allows the Agosta 90B to operate effectively in contested littoral environments, providing a potent anti-shipping and anti-submarine capability. Pakistan acquired three Agosta 90B submarines, the first two built in France and the third assembled in Pakistan, significantly enhancing its underwater warfare capabilities in the Arabian Sea. *Khalid* was the first of this class to be commissioned.

The primary role of the S 137 *Khalid* is anti-submarine warfare (ASW) and anti-surface warfare (ASuW). The TSM 2233M Scylla sonar suite, incorporating both the DSUV 2H hull-mounted active/passive sonar and the DUUA 2D towed array, provides long-range detection and tracking capabilities against both surface vessels and submarines. The TRS 3100 Calypso III (DRUA 33C) radar supports surface navigation and target acquisition. The integration of the TSM 2255 fire control system enables the effective deployment of torpedoes against detected threats. Furthermore, the submarine's low acoustic signature enhances its ability to conduct covert surveillance and reconnaissance operations in strategically important areas. The presence of a signal ejector suggests a capability for deploying countermeasures or communications buoys.

The *Khalid*'s sensor suite is optimized for both active and passive detection. The DR 3000U electronic support measures (ESM) system allows for the detection and identification of radar emissions from surface vessels and aircraft, providing valuable situational awareness. The TSM 2933 Lamproie intercept sonar augments the passive detection capabilities, specifically tailored for intercepting and classifying enemy sonar signals. For close-range operations and target identification, the submarine is equipped with both a standard optical periscope and a low-light television (LLTV) periscope. These periscopes are critical for visual confirmation and target identification in situations where active sonar use is undesirable. The TSM 2243 fire control system further supports the submarine's weapon delivery capabilities.

SPECIFICATION: Length: 67.6 m || Beam: 6.8 m || Draft: 5.4 m || Disp: 1490 t

SENSORS: TRS 3100 Calypso III [DRUA 33C] || DR 3000U || TSM 2233M Scylla [DSUV 2H + DUUA 2D] || TSM 2255 || TSM 2933 Lamproie || TSM 2243 || Generic Submarine Periscope, Optical || Generic Submarine Periscope, LLTV

ARMAMENT: Signal Ejector || 533mm TT