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As far as I am aware, Indian service personnel would almost surely need approval from the GoI to be involved in defense-related activities oversees (unlike Western countries like UK & Australia). The fact that Indian personnel were present should mean tacit support from GoI even though ostensibly they are supporting at a personal capacity.

https://swarajyamag.com/defence/thre...on-with-france

Looks like France is going to help us integrate an AIP power unit with our Scorpene class starting with INS Kalvari later in 2024. It seems DRDO has developed this AIP.

This has to be the AIP plug that's been doing the rounds on the blogosphere for a while now. Think we have a schematic of it earlier on the thread. I guess it's in Naval Groups interest to see how well it integrates into their design. I imagine as the OEM they still get access to a fair bit of data from the license built boats.

What's more interesting in the announcement is the potential 3 boat follow on order. Question is, wording makes it sound like they'll come from French yards which doesn't do anything for preserving the production base at Mazagon Docks from the Kalvari build programme.

Good news is these 3 will be built at Maz Docks Mumbai. How I wish it was 6 or 8 and not 3. 5 out of our 7 Kilo class boats and all 4 HDW's are 40 years old now. That is a lot of age for a pressure hull. Sadly we are being compelled to keep this ageing fleet going because of indecision and lack of budgets in the 1990s and early 2000s.

Indian Navy launches Rs 60,000 crore tender for AIP equipped submarines to be built in India.

https://www.msn.com/en-in/money/tops...a33916ebb&ei=4

With the aim of modernising the country's existing conventional submarine fleet, the Indian Navy has kicked off trials for making highly advanced submarines by floating a Rs 60,000 crore tender. The Rs 60,000 crore contract is to build six stealth submarines equipped with Air Independent Propulsion (AIP) technology, enabling prolonged underwater operations.

The Indian Navy has started trials of the competing teams including Larsen and Toubro and Mazagaon Dockyard. The trials of the German submarine's Air Independent Propulsion system were conducted in Kiel in the last week of March in Germany, defence officials informed India Today. The next series of trials would be held in June at the Spanish Navy facility. Spanish Navantia and India's Larsen and Toubro are partners for this mega project.

This is clearly the most important step in 20 years in the Indian submarine world.

Over the weekend I'll post on the two families of submarines that are most likely in this race.

I mean this is good but I'm confused. If the Kalvari follow on got greenlit using an AIP module, why does it sound like there's a fresh tender with totally new designs being floated? Surely just tack on further orders of the AIP Kalvari.

What am I missing here?

To tack on an AIP on a Kalvari boat will be a retrofit job - a little bit like taking your ICE Honda City car and retrofitting an EV+ICE hybrid powerpack. Might also require cutting the hull in two and inserting a section to create the extra volume. Can be done but a highly inelegant solution and any cutting and rejoining of a submarine hull is a job fraught with risk. The whole hull every square inch will need to be surveyed with ultrasound devices for microscopic cracks that could rupture explosively at depth.

The new tender represents submarines in my opinion of a half generation beyond the Scorpene ie designed to be long distance EVs from day one without the cut and patch jobs of our example above. The German designs at least has variants in the 3000 tonne category with extraordinary submerged loitering times.

Just a doubt. If the French subs are so good, why doesn't the French Navy use them at all?

True, on the current spec design, the AIP module was to be a retrofit job to existing hulls, I thought there was a follow on order where the AIP module would be integrated into the hull from the onset - thereby negating the justifiable risks associated with cutting an existing pressure hull to add a new module. This was basically the B spec of the Kalvari class order right?

I guess my confusion and reticence here is to do with timelines and the inevitable delays a fresh Indian defence tender process introduces. If the current Scorpenes are all being brought up to have the domestic AIP, I just feel that maybe in the interests of budget and time constraints it makes sense that we just tack on further Kalvari-B boats so to speak. Sure they're a smaller weight class than this proposed new tender design but it'll likely be cheaper by far too and surely fielding more of the Kalvari boats is in the interests of logistics and the shipbuilding industrial base. By the time additional orders are placed India could be well on its way to multiple decades of operating the type with a robust system for not just spares but yards with expertise in operating the type.

I guess where I'm going with this is the IN's surface vessel template, where they took one hull type and essentially incrementally iterated from it. In the undersea domain the presence of the SSBN project sort of throws that philosophy out the window somewhat but that was driven by strategic needs. For the conventional boat fleet I don't see why the Scorpene platform can't form the genesis point for similar iterative conventional boat classes down the line, building off a nascent but present domestic shipyard base.

But let's hash it out, I want to understand what the differences in the mission profile of these new boats will be from the Kalvari-B spec, ie, what will they be envisioned to do that the AIP equipped boats can't currently offer? Because if we can get 80% of the way with the Kalvari's, then is it worth it from a time, cost, industrial base and force structure view point to add another hull type to the mix?

Presumably the main differences will likely be enhanced range, ability to have some sort of VLS system for lobbing stand off munitions (cruise missiles) and potentially the flexibility to operate special forces modules.

• a) How much further do these new boats need to go on sorties compared to AIP Kalvaris? There's an argument to be made that if being able to chase let's say PLAN boats further out into the IOR or beyond is the aim, then surely that's the remit of the SSN programme boats. But, SSNs are an order of magnitude more expensive than a conventional boat and therefore this could be that cost consideration compromise option. But why then do we not look at forward basing Kalvari boats further out in the IOR (in a scenario where we can afford more of them should we go down that route). With more boats available IN planners would be afforded more flexibility in tasking the boats across the entire purview of the IN's security committments.
• b) Where it breaks down somewhat for the Kalvari is the inclusion of that VLS cells for launching cruise missiles. You'd need to potentially design yet another add on module for this, which again adds time and risk to the existing design, not to mention the Kalvari C-spec now could end up weighing in around that 3000 ton mark for the new boat tender.

Think the Marine National opted for an all nuclear fleet like the other two nuclear NATO powers. Never thought about why they'd do it - not like the French to go in lockstep with the Americans or Brits. The French not opting for SSKs is likely a strategic decision as to the make up and roles of their submarine force rather than any other reason. That being said it does raise an oddity in that they have a fairly robust SSK pipeline on offer for export but with no usage domestically.

The Indian Navy has finished the first round of trials for the P75I contract. The operational AIP was showcased by both the contenders - the German company TKMS demonstrated the technology at sea in an operational Type 212 submarine while the Spanish Company Navantia showcased this on land though they didn't have it integrated into a boat. The Navy is preparing the report on the trials though many seem to think that the Germans would come out on top. Further, the Indian Navy already operated Type 209 subs. The Germans aren't particularly reliable these days as arms suppliers but then the Spanish have also been doing strange things. If you want a reliable Western arms supplier, stick French though the Americans & Brits (if they make anything these days) are better than they used to be!

This will be interesting and if the recent Naval fighter trials are anything to go by, the Navy should move relatively fast.

I'd say the added fact that TKMS has partnered with MDL gives it a bit of weight. An order for them would help preserve the skills base built up over the Scorpene build.

If the IN needs these boats ASAP, you'd think the fact Navantia are yet to field an operational AIP equipped model and therefore would require additional development time would be a drawback.

But like you warn there's always that risk with the Germans at least that they might change their mind about their weapons supply.

INS Arighat - India's second SSBN (nuclear sub with nuclear tipped ballistic missiles) be inducted + India to built 2 SSNs (nuclear subs for conventional attack)

India's second SSBN - the 6,000 tonne INS Arighat with incremental improvements over the first one the Arihant is expected to be commissioned soon "within a month or two". I assume we can't expect a public ceremony for this just like the INS Arihant. The third SSBN - the INS Aridhaman with further improvements will be commissioned next year. India will eventually also build 13,500 tonne SSBN boats.

Further, the original requirement for nuclear attack submarines has been shrunk from the original plan of 6 to just 2 units with the remaining 4 to be approved later. These will take a decade to be inducted (expectedly) with 95% indigenous components (though probably with some Russian and probably even French assistance). India will apparently get another Akula class SSN submarine from Russia on lease to plug the gap till the indigenous ones roll out.

On another note, some interesting videos from Johnny Harris on Submarines, love how the global fleet is visualised in the first video:

https://youtu.be/T5FpD2-TPms?si=MjWRkyesrvX38Vde

https://youtu.be/AecFpnj383A?si=OE-vRzpT1iD7rlw7

Thank you for posting this proud news. Up and away. Onwards and upwards. The success of the SSBN programme as well as the aircraft carrier project is testimony to designer + builder + user working together as one team under one leadership. How I wish the Air Force and HAL learn this and embrace this in toto. Without doubt lessons from INS Arihant have been incorporated into INS Arighat. I wish we get back to a squadron of 6 to ensure one or sometimes two are at sea. With four it will be tight beyond words. Maybe the plan is really to have 8 with the next 4 of a new design. That will mean it will be 15 years from now till we credibly have one SSBN underwater at all times.

My heart simply swells with pride when I read of INS Arighat. 52 years ago in June 1972 as a boy I attended, from the viewing stands, the commissioning of INS Nilgiri, our first Indian built warship. And here today a mere 52 years later we are soon commissioning our 2nd SSBN.

Shaṁ No Varunaḥ
May the Lord of Waters Be Auspicious Unto Us

Ah I saw that Johnny Harris video on Nebula over the weekend - he's always been good at the visualisations. It was nice to see the global fleets displayed in that manner. Very accessible for those who might be new to this domain.

While it's unsurprising that the follow on boat has implemented changes based on feedback from the lead ship of the class, it's still good to see that those changes have been implemented on the second boat. I did find it interesting that the third boat is in line for commissioning a year later - though it makes sense, having that third one will allow for the rule of thirds (one at sea vs one in refit vs one in training). Granted the limited range of the in service K-15, I can see why you'd rather have two SSBNs at sea @V.Narayan but presumably once the K-4 enters service you could have most second strike targets in Pakistan and China covered still by an SSBN out in the IOR.

Speaking of the K series SLBMs, will the earlier boats of the Arihant class continue to field the lower range K-15 once the K-4 enters service or do you reckon they'll have their VLSs altered in a mid life deep refit to accommodate the K-4?

I imagine the 13,500 tonne SSBN will be a class of its own? It's pretty much going to end up being on par with NATO SSBNs at that displacement. Are they building a new reactor for it or would be a case of scaling up the existing 85 MW reactor (upscaling that design or having say two in tandem)?

Downsizing the SSN programme to two boats isn't as bad I think, if that saving is being passed on towards reprioritising the conventional fleet, ie more SSKs. After all a two boat build for the SSN will still keep the programme ticking (and I think achieving 95% indigenisation out the bat would be an astonishing feat). Honestly if they manage that lofty indigenisation quotient, that would truly be an excellent launchpad for a follow on order. The hard yards will be in getting that first boat to water. Though if all the discourse to date is valid, then a lot of the design work for the SSN is already in place, having used elements of the SSBN programme. I'd imagine the design is probably locked and now it's about getting the build programme underway.

To repeat a point I've made earlier - India has an opportunity in the post AUKUS era to essentially be France's SSN rebound. Under Macron, France is increasingly keen to be more assertive globally whilst maintaining their independence, not that far removed from India's own geopolitical stance. I feel there's room for manoeuvre to be bedfellows on the SSN programme. I feel SSBN collaboration is a step too far, despite AUKUS, for anyone, given the strategic importance of those platforms.

Ideally we need on boat at sea in the Bay of Bengal at any time with 5500 kms range ballistic missiles to cover both our unfriendly neighbours.

I am sure the VLS for boat nos 1 was pre-sized to accommodate the larger K-4 when it gets fully operational. In such a case the smaller missile would operate with liners.

I would bet my middle name this is already in quiet discussion at a serious level.