Gessler: Future Indian Nuclear Subs, SLBMs: Comment 3

Following India's 6 Future Alpha SSNs - SSBN Protectors  of April 7, 2021 Gessler made some learned and extensive comments on April 9, 2021. Pete has added many links. Here is the third Gessler instalment:

Keeping in mind the fact that the S-5 class will probably have 12 missile tubes storing future K-5 or K-6 intercontinental SLBMs (which will most definitely have Multiple Independently-targeted Re-entry Vehicles or MIRVs). Each S-5 boat, even if we assume a relatively modest MIRV capacity of 3 RVs per missile, would be carrying 36 nuclear warheads. Three such boats, if we assume each has it's own permanently assigned load of missiles, would require 108 warheads. If we're talking four boats (following the UK and France pattern of SSBN numbers) that goes to 144 warheads. That's close to the total stockpile that most experts assume India to have currently around 150 warheads. 

If we assume 4 MIRVs per SLBM (like the slide here) shown by DRDO's then-chairman Dr. VK Saraswat at IIT-Bombay university.) then it would be 48 warheads per sub, and 144 for Three boats and 192 for Four boats. With a quoted throwaway weight of 2 tons, likelihood is high for there to be indeed 4 x 500kg MIRVs per K-5/K-6.  

Personally I'd definitely assume India has more than 150 nukes even currently, the delays of Plutonium deliveries to the PFBR prototype also point at the possibility of the Pu going to fill other, more pressing & strategically important requirements, like perhaps building more bombs. By the time the S-5s come online, I'd certainly expect us to have more than 150. 

However - it must be remembered that India, with two hostile neighbours who share land borders, certainly has no plans of giving up it's land-based rail and road-mobile nuclear deterrent like UK & France have done. This portion of the triad will continue to be armed in the form of Agni-4, 5 and the in-development Agni-6 with MIRVs. The Agni-6 is reportedly designed to have a throw weight of 3 tons, so we're again looking at a significant MIRV payload (again, refer to the slide here from same source at IIT-Bombay presentation). 

And we won't be giving up the Air-launched deterrent either (like UK has done), the presence of nuclear gravity bombs as well as the ongoing development of a nuclear-capable Liquid-Fuel Ramjet controlled (LFRJ)  ALCM intended for the Indian Rafales (very similar to the French ASMP-A missile  also see and here   ) indicate that this leg of the triad is here to stay as well. 

What all this means is that we'll be needing a significant number of warheads (at least 100) outside of CASD as well. And this just goes to show that there's no way we can continue operating Arihants as nuclear-armed SSBNs even after S-5s come in. We just won't have enough nukes for them, and that's just part of the reason compelling us to convert the Arihants into conventionally-armed SSGNs in the 2030s - poised to be the ideal platform for cruise missile strikes on likes of Karachi's naval facilities/airbases or any Chinese naval presence at Gwadar in the event of open hostilities."