Six Advanced Conventional Submarines to be Built under Project 75 India
The defence ministry cleared a project worth Rs 43,000 crore for building six advanced conventional submarines in India under Project 75 India (P75I). Indian Navy is soon expected to issue requests for proposal (RFP). This is one of the largest ‘Make in India’ projects and will serve to facilitate faster and more significant absorption of technology and create a tiered industrial ecosystem for submarine construction in India.
Strategic Partnership (SP) model is being utilised in this project. The SP model envisages indigenous manufacturing of major defence platforms by an Indian Strategic Partner who will collaborate with a foreign Original Equipment Manufacturer (OEM) to set up production facilities in India. The Indian strategic partners cleared to collaborate with the foreign OEMs are Mazagon Dock Shipbuilders Limited and L&T. The foreign OEM with which strategic partners can team up with for the project are:
- The French Naval Group,
- German conglomerate Thyssenkrupp Marine Systems,
- Russia’s Rubin Design Bureau,
- Spain’s Navantia and
- South Korea’s Daewoo Shipbuilding & Marine Engineering Company.
The availability of new technologies and advanced manufacturing capabilities to the industry will be an important step towards enhancing the nation’s quest for self-reliance in modern conventional submarine construction. The project will take time to mature and if all goes well, the first submarine will be delivered to the Indian Navy in 10-12 years’ time from now.
The navy plans to operate a fleet of 18 new conventional submarines and six nuclear-powered submarines in the future. The Submarine being built under P75 project will be equipped with Air Independent Propulsion (AIP) systems that will enable the vessels to stay underwater for longer periods and enhance their combat capabilities. The submarines will also be equipped with missiles & torpedoes.
Note:
- Submarines are essentially of two types: Conventional and Nuclear. Conventional submarines use a diesel-electric engine and must surface or snorkel daily for oxygen & for running diesel-electric engine (to charge their batteries). The Nuclear submarines run on nuclear plants and do not require to surface for days. However, a conventional submarine fitted with an Air Independent Propulsion (AIP) system needs to take in oxygen only once a week.
While many naval powers, including India, have acquired nuclear-powered submarines for deep-sea operations, conventional diesel-electric variants are considered useful for coastal defence. The conventional submarines are optimised for stealth, and their weapons and sensors provide for effective operations close to the shore.
- AIP uses various methods like closed cycle diesel, fuel cells, Stirling engines, closed cycle gas to extend the durability of submergence under water.
- In a fuel cell AIP, an electrolytic fuel cell releases energy by combining hydrogen and oxygen, with only water as the waste product. The cells are highly efficient, and do not have moving parts, thus ensuring that the submarine has a low acoustic signature. Older submarines can be adapted to the AIP system by retrofitting. ‘Air-independent’ propulsion technology helps to make the diesel generator less dependent on surface air. The DRDO’s AIP technology is based on a Phosphoric Acid Fuel Cell. And an additional hull section has to be added to the existing submarine to get the benefits of the AIP system.
- AIP equipped submarines are called SSP while the diesel attack submarines are called SSK.
- Stirling engine is one kind of external combustion engine which converts thermal energy into kinetic energy by heating and cooling the working gas sealed in the cylinders. Thermal efficiency of Stirling cycle is as high as Carnot cycle which theoretically has the highest thermal efficiency. Combustion of fuel is continuous, so it is rather easy to control exhaust emission. Stirling engine has high possibility to achieve low level of noise and vibration because cyclic torque fluctuation is smooth thanks to non-explosive combustion. This improves the durability and reduces the cost of components.
- The Indian Navy is also in the process of procuring 57 carrier-borne fighter jets, 111 Naval Utility Helicopters (NUH) and 123 multi-role helicopters under the strategic partnership model.
- The Defence Ministry has set a goal of a turnover of Rs 1.75 lakh crore in defence manufacturing in the next five years that includes an export target of Rs 35,000 crore worth of military hardware.