How The Indian Navy Is Ensuring High Indigenous Content In Its Project-75(I) Submarines
The P75I project is part of a 30-year submarine building plan that ends in 2030. As part of this plan, India was to build 24 submarines — 18 conventional submarines and six nuclear-powered submarines (SSNs) — as an effective deterrent against China and Pakistan.
Of the 14 conventional submarines India currently possesses, including the Scorpene, only half are operational at any given point of time. India also has two nuclear-powered submarines — INS Arihant (SSBN, a ballistic missile submarine) and INS Chakra (SSN, a nuclear-powered one) leased from Russia.
The Project 75I-class submarine is a follow-on of the Project 75 Kalvari-class submarine for the Indian navy. Under this project, the Indian Navy intends to acquire 6 diesel-electric submarines, which will also feature advanced Air Independent Propulsion (AIP) systems to enable them to stay submerged for longer duration and substantially increase their operational range.
The six new submarines for the P-75I project is the next phase of the same submarine project and will be worth over $ 11.10 billion. According to the Indian Navy, the new submarines will differ from the earlier lot since the qualitative requirements have been altered. The new submarines will have air-independent propulsion (AIP) to enable sustenance under water for longer duration. In addition, there will be advanced detection range and combat management system besides better sensors for optimum performance. The weapon system would be a mix of torpedoes and missiles.
The six new submarines in P-75 I project will outline various critical parameters including the weight and design of the submarine. The Project 75I submarines are expected to be bigger than the 1800-ton Scorpene class being built for P-75 project.
Today, a large number of its surface vessels are constructed by Indian shipyards with indigenous content going up to 81 per cent in some cases.And now, this trend is also becoming evident in the construction of submarines. The Kalvari-class (Scorpene-class) submarines of the Indian Navy, some of which are currently under construction at the Mumbai-based Mazagon Dock Limited, have between 30 to 40 per cent indigenous content. While indigenous content on the Kalvari-class boats is not exceptionally high due to contract stipulations, the Indian Navy has sought to do away with this restriction in Project-75 (I), under which six conventional submarines are to be built in India.
Among other things, the navy has asked for the indigenisation of pressure hull steel, introduction of indigenous Air-Independent Propulsion (AIP) module, and the integration of home-grown torpedos and submarine-launched cruise missile on its Project-75 (I) submarines to increase the level of indigenous content.
1) Air-Independent Propulsion
The navy wanted the indigenously Air-Independent Propulsion (AIP) module, developed by the Naval Materials Research Laboratory, installed on the last two of its six Kalvari-class diesel-electric submarines being built by the Mazagon Dock. However, delays derailed the plan. Now, the navy wants the module to be introduced on the submarines to be built under Project-75 (I).
The module, which is capable of significantly increasing a submarine’s underwater endurance, was in an advanced stage of trials as of March 2018.
The use of AIP on a diesel-electric submarine, greatly increases their underwater endurance, allowing them to continuously stay submerged for weeks without surfacing. Although the submarine eventually needs to surface to charge its batteries and their endurance is nowhere on-par with nuclear powered submarines, the vast increase in endurance offered by AIP gives them an advantage over non AIP equipped diesel-electric submarines. However AIP doesn’t give any advantage other than increased underwater advantage and it should not be assumed that AIP-equipped submarines will always defeat their non-AIP equipped counterparts.
The Indian Navy is also planning to introduce the AIP module on its Kalvari-class boats when they go for first major refit. The first of the Kalavari-class, INS Kalvari, inducted in 2017, is expected to go for refit around 2023.
2) Heavyweight Torpedoes
In 2013, when the VVIP chopper scam surfaced, the Congress-led United Progressive Alliance government banned not just AgustaWestland, the maker of the helos, but the entire group – Finmeccanica – of which it was a part. This whimsical blacklisting ended up costing the navy dear. An order for 96 Black Shark heavyweight torpedoes, which were to being procured for the Kalvari-class and Arihant-class boats of the Indian Navy, was cancelled because these were built by Whitehead Alenia Sistemi Subacquei, a company part of the banned Finmeccanica group.
As a result, the navy had to induct INS Kalvari and INS Arihant without new heavyweight torpedoes. INS Kalvari currently shares 64 obsolescent, unreliable German SUT torpedoes with four HDW Shishumar-class boats.
Taking lessons, the Navy has asked for the integration of indigenous heavyweight torpedoes on the boats to be built under Project-75 (I).
The Defence Research and Development Organisation has developed a heavyweight torpedo – Varunastra – for surface ships, and, reports say, is currently working on a submarine-launched version. Given the relatively high cost of imported torpedoes, an Indigenous one will be a boost for the navy.
Varunastra, which has a range of around 40 kilometers, has been inducted by the navy for use by its surface vessels. The navy has ordered 73 of these. It can be used from Kolkata, Delhi, Teg, Talwar and Kamorta-class vessels.
3) Submarine-Launched Cruise Missile
The Indian Navy wants its Project-75 (I) boats to be capable of carrying 12 land-attack and anti-ship cruise missiles.
India currently has two cruise missiles – the in-service supersonic BrahMos and the under-development subsonic Nirbhay. In all likelihood, a version of the BrahMos cruise missile will equip the Project-75 (I) boats. According to its maker, BrahMos Aerospace, the missile can be fired from a depth of 40-50 meters, and all stimulation trials related to underwater launch have been completed.
BRAHMOS missile is capable of being launched from submarine from a depth of 40-50 metres. The missile can be installed in a modular launcher vertically in the pressure hull of the submarine. The missile has identical configuration similar to the ship based system.
The canisterised missile is launched vertically, the nose cap prevents water from entering the ‘air-intake’ during the underwater flight. Once the missile emerges from the water, the sensors provide the out of water command and the nose cap is fired for turning the missile in the desired direction to hit the target.
BRAHMOS installation in submarine will increase manyfold the ‘offensive power’ of the vessel without compromising on its ‘defensive power’ as the torpedo tubes can be fully utilized for defence. All studies and simulation trials related to underwater launch have been completed.
Apart from reducing the import cost, integration of a home-grown cruise missile will address the issue of availability and upgrade. An indigenous system is much more likely to be available to the navy at short notice, and, most importantly, will be much easier to upgrade for future use than one which is imported. As the BrahMos is also used by a number of surface vessels of the navy, commonality will be another major advantage of its integration on new submarines.