With new propulsion, last of six Scorpene subs needn't surface so often

As India develops its air independent propulsion (AIP) technology that enables a submarine stay underwater for longer periods without having to constantly surface to charge its batteries, the last of the six boats being built in the country may benefit from the system.

While the initial plans were to fit at least two of the six submarines with the system, an Indian Navy officer said the technology may not be ready in time to install it in the fifth Scorpene submarine.

"The technology is being developed, and it may miss the fifth submarine, but we hope to get it on the sixth one. Everything depends on the development of the AIP system," an Indian Navy official told IANS.

He said another option was that the AIP system could be installed in the fifth Scorpene submarine later on.

"Maybe it can be retro-fitted in the fifth submarine later," the officer said.

The AIP system being developed by the Maharashtra-based Naval Materials Research Laboratory (NMRL) is a fuel cell that replaces diesel in conventional submarines. It

converts methanol-like substances to produce hydrogen, which is the fuel that runs the cell in producing electricity.

While diesel engines need oxygen to function, these cells are air independent. The sustem also emits less noise, increasing its stealth - the most critical feature of a submarine.

With this system, a conventional submarine that needs to surface every three to four days for replenishing its oxygen supply, can stay underwater for up to two weeks.

Developing the technology will cost India about Rs 50,000 crore ($7 billion).

On the other hand, submarines of archrival Pakistani Navy, mostly procured from France, are equipped with the AIP.

In 2005, India purchased six Scorpene submarines from France for US$3 billion. They are being manufactured under a technology transfer agreement by the state-owned Mazagon Docks in Mumbai in collaboration with the French group DCNS.

The submarines were initially to be delivered between 2012 and 2016.

The project is however running almost four years behind schedule, and first of the six submarines, INS Kalvari, is currently undergoing sea trials and is expected to be inducted into the Navy in 2016.

According to the navy officer, two more submarines are in the outfitting phase.

The Scorpene submarines are designed to operate in all theatres, including the tropics. They can undertake various types of missions like anti-surface warfare, anti-submarine warfare, mine laying, intelligence gathering and surveillance.

The submarine arm of the Indian Navy has been facing constraints in the recent past as most of its Soviet-era vessels have outlived their intended life. A couple of such submarines have also been involved in serious accidents, resulting in the loss of precious lives.

(Anjali Ojha can be contacted at anjali.o@ians.in)