Varunastra Shakti heavy weight torpedo HWT Indian Navy

Submarine Weapon System
Varunastra / Shakti heavy weight torpedo - HWT

varunastra heavy weight torpedo hwt 533 mm 21" indian navy drdo bharat dynamics 03

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The Varunastra (lit. 'Astra (weapon) of Varuna') is an Indian advanced autonomous heavyweight anti-submarine torpedo, developed by the Naval Science and Technological Laboratory (NSTL) of the Defence Research and Development Organisation (DRDO) for the Indian Navy. It is named after a legendary weapon created by the Hindu god of the oceans, Varuna.

This torpedo is powered by an electric propulsion system with multiple 250 kW (340 hp) Silver Oxide-Zinc (AgOZn) batteries. It can achieve speeds in excess of 40 kn (74 km/h; 46 mph), weighs around 1.5 tonnes and can carry 250 kg (550 lb) of conventional warhead. This torpedo has more than 95 per cent indigenous content. Varunastra has conformal array transducer which enables it look at wider angles than most common torpedoes. It also has an advanced autonomous guidance algorithms with low drift navigational aids, insensitive warhead which can operate in various combat scenarios. It is the only torpedo in the world to have a GPS-based locating aid. The exercise variant of Varunastra has integrated instrumentation system for recording all the dynamic parameters of the weapon, redundancy in recovery aids in case of emergency shut down or malfunction.

Further development:

Shakti - Thermal Heavy Weight Torpedo:
Shakti heavyweight torpedo uses thermal propulsion technology in contrast to the Varunastra torpedo which uses electric propulsion. The torpedo employs monopropellant fuel, which allows combustion to take place without aerial oxygen, and a pumpjet. Its propulsion unit generates 400 kW of power for faster acceleration. A newer propulsion unit is under development which will be producing 500 kW of power .It can operate at a maximum depth of 600 metres (2,000 ft), a maximum speed of 60 knots (110 km/h; 69 mph). The Torpedo is expected to be used on India's P-77 and S5 class submarines, as well as older Sindhugosh class.

Takshak - Electronic Heavy Weight Torpedo:
Takshak torpedo is the advanced version of the Varunastra torpedo which employs an electric battery for propulsion. It has a length of 6.4 metres (21 ft) which is shorter from the previous variant, enabling to be launched from submarines. The torpedo had a range of 40 km (25 mi) and maximum depth of 400 m (1,300 ft). Takshak uses a “swim-out” launch system, which launches torpedoes without compressed air and minimises acoustic signature during launch. It also features ring laser gyro inertial navigation system (RLG INS) as well as GPS/NavIC-based guidance. Takshak has 2 variants: submarine-launched with optical fiber guidance and ship-launched with autonomous guidance. By May 2024, the torpedo was ready for sea trials with the Indian Navy which would pave way for its induction and deployment.

On 30 December 2024, the Indian Ministry of Defence (MoD) signed a contract, worth US$97 million), with the French Naval Group to integrate DRDO developed Electronic Heavy Weight Torpedo Takshak (EHWT) on Kalvari class submarines. The guidance software of the torpedo will be integrated with the Submarine Tactical Integrated Combat System (SUBTICS) of the Kalvari submarines.

A Wire Guided Heavy Weight Torpedo (WGHWT) is also under development with the DRDO as of 2026. It is a submarine launched torpedo with high speeds. WGHWT and EHWT could be different designations for the same design. The first production grade was delivered by BDL from its Hyderabad facility to NSTL's Visakhapatnam unit on 25 April 2026.

Specifications:
Mass: 1,500 kg (3,300 lb)
Length: 7.78 m (25.5 ft)
Diameter: 533.4 mm (21.00 in)
Warhead: 250 kg (550 lb) High explosive
Engine: Electric drive; Silver Oxide Zinc (AgOZn) batteries
Operational range: 40 km (25 mi) to 50 km (31 mi)
Maximum depth: 600 metres (2,000 ft)
Maximum speed: 40 knots (74 km/h; 46 mph) to 50 knots (93 km/h; 58 mph)
Guidance system: Fiber Optic Wire-guided, active-passive acoustic homing + multi-GNSS
Launch platform: surface ship, submarine

Designer: Naval Science and Technological Laboratory (DRDO)
Manufacturer: Bharat Dynamics Limited, Hyderabad, India

sources: wikipedia, Indian Navy

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varunastra heavy weight torpedo hwt 533 mm 21" indian navy drdo bharat dynamics 02

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