Project-75I Next-Generation Diesel-Electric Submarines: Indian Navy Concludes Trials Of AIP Systems From Germany And Spain

Indian Navy has completed the performance evaluation trials of the Spanish firm Navantia's offering for the navy's P-75I six new generation diesel-electric attack submarines.

Earlier in March, the Navy completed trials of the offering from the second contender of the project, Germany's ThyssenKrupp Marine Systems (TKMS).

The major focus of the trials was on the air-independent propulsion (AIP) system offered by both companies.

According to reports, Navantia's S-80 submarine and its AIP system's performance on the surface were evaluated by Indian Navy officers last week, while its submerged performance will be demonstrated soon.

AIP systems, as the name suggests, are systems that allow a diesel-electric submarine to recharge its battery while remaining submerged instead of using its noisy diesel engines, which increases its chances of detection by the enemy.

Moreover, when using its diesel engines, the submarine has to come very close to the surface, called snorkelling in naval parlance, where the submarine comes very close to the ocean surface and juts out a pipe over the surface to get rid of the exhaust generated by diesel engines.

The movement of the submarine from the depth to the ocean's surface and the smoke from the diesel engines increase its chances of detection. AIP ensures the batteries are charged independently while remaining submerged, increasing their endurance and stealthiness.

Both TKMS and Navantia have partnered with Indian shipbuilders, Mazagaon Shipyard Limited (MDL) and Larsen and Toubro (L&T), where all six submarines will be built in India with transfer of technology (ToT).

It is reported that the first submarine will have 45 per cent indigenous content, which will be increased to 60 per cent by the time the last submarine is built.

The navy officers will present these findings to the Defence Ministry, which is likely to give impetus to the Rs 43,000 crore project that has been stuck for more than a decade and a half.