India’s 651 kW Indigenous Water-Jet Propulsion System by DRDO and L&T Achieves Sea Trial Success

India has achieved another milestone in its journey toward defence self-reliance with the successful preliminary sea trials of a powerful, indigenously developed 651 kW Water-Jet Propulsion System. This advanced marine technology has been developed jointly by the Defence Research and Development Organisation (DRDO) and private-sector giant Larsen & Toubro (L&T) under the DRDO’s Technology Development Fund (TDF) scheme. The successful testing took place aboard one of the Indian Navy’s Fast Interceptor Crafts.

This new propulsion system is not just a technological upgrade—it represents a major leap in India’s ability to design and produce cutting-edge naval equipment. What makes it even more significant is that the system is designed entirely in India, with more than 70% of its components being indigenously sourced. It’s a true reflection of the government’s ‘Aatmanirbhar Bharat’ (self-reliant India) vision, particularly in the strategically important defence sector.

Unlike conventional systems that use external propellers, this water-jet propulsion mechanism uses a high-powered pump to draw water in and expel it at high speed to create thrust—based on Newton’s third law of motion. This design provides superior control, rapid acceleration, and enhanced manoeuvrability. Such features are especially critical during high-speed operations in shallow coastal waters or in tight maritime zones, where precision and quick response are key.

One of the standout advantages of this system is its low acoustic signature. Because there are no exposed propellers and the water flow is managed internally, the system generates less noise and vibration. This stealth capability is essential during covert naval missions, surveillance patrols, or anti-smuggling operations where avoiding detection is crucial. Additionally, the internalized mechanics result in less wear and tear, making the system more reliable and easier to maintain over time.

The successful preliminary sea trials confirm that the system performs efficiently in real operational environments. According to defence insiders, further trials and refinements will likely follow, but the success so far opens the door for widespread deployment of the system in India’s growing naval fleet. It is expected to power a range of Fast Interceptor Crafts and small patrol vessels used by the Navy and Coast Guard for coastal defence, high-speed interdiction, and maritime surveillance missions.

This achievement also highlights the increasing importance of private-sector players like L&T in India's defence landscape. With access to advanced manufacturing facilities and engineering talent, such collaborations are accelerating the pace of innovation and reducing dependency on foreign technology.

In the broader context of national security and maritime dominance, this development positions India to better secure its coastline, monitor its waters, and respond rapidly to emerging threats—entirely with homegrown technology.