The Navy is planning to instal Air Independent Propulsion (AIP) modules on all six Scorpene submarines to extend their endurance. This will be done when the submarines go for normal refit which is six years after their induction.
“Yes, the Navy plans to instal the AIP plugs during the refit for all the six submarines,” defence sources told The Hindu .
However, officials said that it was a long and expensive process, involving re-designing, as it would entail opening up the hull of the submarine, then integrating the plug before resealing it.
“The AIP has to be ready and has to be validated and certified. Then the submarine design has to be redesigned as well since the plug has to be integrated. This means conducting the full set of trials and certifications before the submarine is back in service,” one official told The Hindu .
The first Scorpene submarine Kalvari is all set to join the Navy by August and would go for its normal refit in 2023. The remaining five submarines are expected to be inducted at nine-month intervals.
The official said preparation for the AIP provision has to begin right away to be able to meet the timelines. “It would require approval at the highest levels. That will also take time,” he added.
This also means that the time of the refit would be extended. Generally a normal refit takes between 12-18 months.
Increased performance
AIP module is not part of the original Scorpene contract but the Navy has been keen on having them fitted on the last two of the six Scorpene submarines being manufactured by the Mazagon Dock Limited (MDL) in Mumbai.
An AIP module is being developed by the Defence Research and Development Organisation (DRDO) and was supposed to be installed on the last two submarines before they roll out of the production line.
However, delay in the module’s development seems to have scuttled the plan.
The module enables conventional submarines to remain underwater for longer duration, greatly increasing their stealth characteristics.
Bernard G. Buisson, Managing Director of DCNS, told The Hindu earlier that there was no chance of installing the plugs on the 5th and 6th submarines now and the only way would be installing them during the refit.
