OVERVIEW: The S 20 *Kursura* [PL-641M Foxtrot] is a diesel-electric powered submarine operated by the Indian Navy. Built in the Soviet Union and designated a Project 641M variant, the *Kursura* represented a significant addition to India's submarine capabilities at the time of its commissioning.

DETAILS: The Project 641 (Foxtrot-class) submarine was developed in the Soviet Union as a successor to the Project 611 (Zulu-class) submarine, addressing shortcomings in underwater speed and sensor capabilities. The Foxtrot design emphasized improved submerged endurance, enhanced sonar performance, and a larger torpedo armament. The "M" designation indicates a modernization program, likely involving upgrades to sensors, communications equipment, or internal systems for improved operational effectiveness in the Indian Ocean environment. The *Kursura*, commissioned in 1968, provided India with a considerably more capable submarine platform compared to its earlier, smaller acquisitions. The acquisition of Foxtrot-class submarines from the Soviet Union was instrumental in establishing India's submarine arm and developing the expertise required to operate and maintain sophisticated underwater warfare assets.

The *Kursura*, like other Foxtrot-class submarines, primarily fulfilled anti-surface warfare (ASuW) and anti-submarine warfare (ASW) roles. Its extended submerged endurance allowed for patrols and surveillance missions far from friendly ports, enabling the Indian Navy to project power and monitor maritime activity in the region. The submarine also likely played a role in intelligence gathering, monitoring shipping lanes and potential adversaries. The *Kursura*'s operations included participation in naval exercises, coastal defense patrols, and potentially covert missions, contributing to India's maritime security objectives. The training value it provided to generations of Indian submariners was also substantial.

The S 20 *Kursura* was equipped with a comprehensive suite of Soviet-era sensors. The installation of the Pike Jaw [MG-200 Arktika] and Wolf Paw [GAS-372 Hercules-2M] sonar systems provided significant advantages in detecting and tracking both surface and subsurface contacts. The Wolf Paw, in particular, was a capable active/passive sonar system for its time, enabling relatively long-range detection. The Acoustic Intercept [MG-23 Svet-M] system enhanced the submarine's ability to passively locate enemy vessels by analyzing their sonar emissions. The Snoop Tray 1 [RLK-101 Albatross] radar system was essential for surface navigation and target acquisition when operating on the surface. The armament of 533mm torpedo tubes provided a potent offensive capability against surface ships and submarines, further enhancing its operational effectiveness. The Quad Loop DF presumably aided in radio direction finding.

SPECIFICATION: Length: 91.3 m || Beam: 7.5 m || Draft: 5.1 m || Disp: 1952 t

SENSORS: Quad Loop DF || Stop Light B [Nakat] || Trout Cheek [MG-10M Feniks-M] || Snoop Tray 1 [RLK-101 Albatross] || Acoustic Intercept [MG-23 Svet-M] || Pike Jaw [MG-200 Arktika] || Wolf Paw [GAS-372 Hercules-2M] || Generic Submarine Periscope || Optical

ARMAMENT: 533mm TT