INS Sindhudhvaj (S56): a submarine of strength and versatility – exploring its general characteristics

INS Sindhudhvaj (S56), a famous Sindhughosh-class submarine of the Indian Navy, served dutifully from 1987 till it was decommissioned on July 16, 2022. It was renowned for its technological brilliance, integrating modern equipment, completing a historic deep-sea rescue mission, and receiving the Chief of Naval Staff’s Innovation Trophy.

INS Sindhudhvaj (S56), a famous Sindhughosh-class submarine in the Indian Navy, served dutifully from 1987 to July 16, 2022, as it was decommissioned. The name Sindhudhvaj, which translates to ‘flag bearer at sea,’ represented the submarine’s status as a steadfast protector of the waterways. Notably, the sub’s logo depicted a grey nurse shark.

Sindhudhvaj was instrumental in the operationalization of numerous indigenously built systems, showcasing India’s technological strength. Among these accomplishments was the successful integration of the USHUS sonar, Rukmani and MSS satellite communication systems, inertial navigation systems, and torpedo fire control systems.

One of the submarine’s greatest accomplishments was a successful mating and crew transfer with a deep-submergence rescue vehicle, proving its improved capabilities in difficult underwater situations. Sindhudhvaj was also the only submarine to be awarded the Chief of the Naval Staff’s Rolling Trophy for Innovation, a high honour conferred by Prime Minister Narendra Modi. This award recognised the submarine’s outstanding contributions to naval innovation and technological achievements over its years of service.

General Characteristics:

The INS Sindhudhvaj (S56) is a Sindhughosh-class submarine with a surface displacement of 2325 tonnes and a submerged displacement of 3076 tonnes. The vessel has a length of 72.6 metres, a beam of 9.9 metres, and a draught of 6.6 metres. It has a powerful propulsion system with two 3,650 hp diesel-electric engines, one 5,900 hp motor, two 204 hp auxiliary motors, and one 130 hp economic speed motor. 

In terms of performance, the submarine can reach 11 knots when surfaced, 9 knots in snorkel mode, and a remarkable 19 knots while submerged. Its operating capabilities include a 6,000-mile snorting range at 7 knots and a 400-mile submerged range at 3 knots, demonstrating its versatility and endurance, which can last up to 45 days with a crew of 52.

The INS Sindhudhvaj is equipped with a 9M36 Strela-3 (SA-N-8) SAM launcher, Klub-S (3M-54E) Anti-Ship Cruise Missile (ASCM), Type 53-65 passive wake homing torpedoes, and TEST 71/76 anti-submarine torpedoes. It may also carry 24 DM-1 mines rather than torpedo tubes, which increases its strategic potential.

The submarine can reach an operational depth of 240 metres and a maximum depth of 300 metres. The INS Sindhudhvaj has a complement of 52 people, including 13 officers, which reflects the crew composition needed for optimal mission execution. This submarine is a strong asset with a diverse set of features that ensure its efficacy in a variety of maritime circumstances.