DRDO Plans to Develop AIP System for Submarines

India Defence Online, New Delhi — The state-owned Defence Research and Development Organisation (DRDO), with the help of its laboratories, is working on the development of a land-based demonstrator followed by the creation of an Air Independent Propulsion (AIP) system that will revolutionise the functions of the current diesel and electric submarines.
The DRDO is going full steam ahead with this project at the Naval Materials Research Laboratory (NMRL) at Ambernath in Maharashtra since the Indian Navy has gladly accepted the proposal by the DRDO. The creation of a fully operational version of an AIP will substantially cut down the time spent by the submarine on snorting or resurfacing for battery recharge. The creation of the AIP will considerably improve the sub-surface performance of the submarines and decrease its susceptibility to attacks.
According to DRDO sources, work on a land-based prototype will be initiated after which they will move to engineering a submarine platform. Sources said that the DRDO has been requested by the Indian Navy to create a fully engineered fuel cell AIP by 2014. This will enable the possible use of the indigenous AIP in the last two of the six Scorpene submarines being built in Mumbai’s Mazagaon Dock Limited (MDL).
The Project-75 India or P-75I involves all the six new submarines being equipped with air-independent propulsion (AIP) systems to boost their operational capabilities. DCNS had bagged the contract for supplying six Scorpene submarines to India under a contract signed in 2005. Three of the six submarines are being constructed at Mazagon Docks Limited (MDL) in Mumbai and one at Hindustan Shipyard Ltd (HSL) in Visakhapatnam, with the help of a foreign collaborator.
The current DRDO endeavour for creating the land-based prototype and the engineered AIP is focused mainly on the Indian Navy and its operational needs.  The French defence firm DCNS has offered to install its MESMA AIP in the last two Scorpenes submarines. However, India has not committed anything since it will wait for the platform that will be available during the induction time.
The DRDO also guaranteed a higher level of safety to the submarine with its AIP for the submarines. Since the submarine requires high amounts of hydrogen to stay underwater for longer durations, hydrogen is stored on-board. However, high-pressure hydrogen is a potential explosive hazard. The DRDO has devised the means to generate hydrogen online. Hence, the hydrogen will be created as per need and do away with all the hassle of storage. Besides that, phosphoric acid fuel cells will be used to offset the impurities in the hydrogen created on-board.