MAY THE BEST AIP WIN

Navy's choice between German and Spanish submarines could boil down to who has the best Air Independent Propulsion

- AJAI SHUKLA

Mumbai-based Mazagon Dock Ltd (MDL) is poised to deliver to the Indian Navy the last of six Scorpene, Kalvari-class, diesel-electric submarines built under the Project 75 programme.

Now attention is shifting to Project 75(I), the programme to build another six submarines powered by Air Independent Propulsion (AIP).

These are running far behind the timeline in the Ministry of Defence's (MOD's) 30-Year plan, approved by the Cabinet in 1999, to build 24 conventional submarines by 2029.

With the technology and experience acquired from Project 75 and Project 75(1), Indian designers and shipyards are to build the remaining 12 submarines in India as Project 76 - a fully indigenous effort, from design to delivery, with no foreign support.

While conventional diesel-electric submarines can operate underwater for no more than 48 hours, submarines with AIP can remain underwater for up to two weeks before they must surface for battery charging.

That provides significant operational advantages over legacy diesel-electric submarines, which are easily detected by enemy radar, which spots masts or snorkels protruding out of the water while they recharge batteries.

The tender for Project 75(I) is also crucial for Project 76 in three critical ways. First, the foreign partner chosen for Project 75(I) -designated the "original equipment manufacturer", or OEM must demonstrate possession of a fuel cell-based AIP system that is operational on board a submarine at sea. Second, the OEM must be willing to transfer the entire submarine design to India. Third, Project 75(I) is required to be processed under the Strategic Partnership (SP) model, described in Chapter 7 of the Defence Procurement Procedure of 2016 (DPP 2016).