November 3, 2014: The fifth and sixth Project 75 Scorpene submarines to be built at Mazagon docks will feature DRDO developed Air Independent Propulsion (AIP), which will be ready for sea trials by February 2015
Without AIP, a Scorpene sub can stay underwater for a maximum of four days; thereafter it needs to surface and re-charge its batteries using diesel gensets. French firm DCNS, which developed the Scorpene, has its own 300-t, second generation AIP plug that can allow the boat to stay under water for as much as three weeks, but the Indian Navy has opted to go with a DRDO developed AIP which has been proven on a land-based prototype.
DRDO DG (Naval Systems & Materials), V. Bhujanga Rao told The Hindu that the French MESMA AIP being offered for the Scorpenes is an old system with a steam turbine.
According to Rao, the DRDO AIP could later be reconfigured for the submarines to be acquired under Project 75I .
Earlier, the Indian Navy asked MDL to equip the fifth and sixth boats with Air Independent Propulsion by fitting an additional section.
The four Scorpenes launched earlier could be retrofitted under an upgrade program.
Philippe Berger, former submariner and submarines operational marketing manager of DCNS, told Indian journalists in October 2014 that DRDO will be fully responsible for its AIP plug.
"Our scheme is limited to integrating safely the DRDO-developed AIP plug to the submarine. We are working on designing the hull section in detail for this,” Mr. Berger told Indian journalists at the DCNS facility, which houses the “fully tested operational-scale fuel cell AIP.”
IDP Sentinel members can read more about Indian Navy's Project 75 Scorpene subs at the link below
Project 75 Scorpene Submarines (IDP Sentinel)