P-77 SSN: Indian Nuclear Attack Submarine Project

[Fatalis]

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Just an observation of mine. The older S5 model looks similar to the Type 094 SSBNs of PLAN, specifically the hump and transition from hump - upper hull. Any opinions?

I also feel like the number of missiles might have gone up from 12 to 16 just from looking at the sheer length of the compartment.

 

[Gessler]

View attachment 16641View attachment 16642
Just an observation of mine. The older S5 model looks similar to the Type 094 SSBNs of PLAN, specifically the hump and transition from hump - upper hull. Any opinions?

It's what @SwordOfDarkness said.

That's the only way to fit large missiles into a hull this size.

The Chinese weren't the first to do it either. You can find similar, large humps on the Soviet Delta-class SSBNs as well.

IN seems to have accepted the cost of larger sub to have better performance in S5.

Personally, I don't think so. Going for a larger beam (diameter of hull) would mean essentially going back to the drawing board & starting from square one. That would induce years of delay.

I think the reason why we largely eliminated the hump is because of advancements in missile technology i.e. we're able to reach the same range with same payload as before, but with a shorter missile. Which in turn must have informed submarine design.

The beam of Ohio and Delta IV is not that different (13.0m vs 12.3m = 0.7m diff), but the Ohio's Trident-II missile is much shorter than R29RMU Sineva (13.6m vs 14.8m = 1.2m diff). The difference amount of 0.5m is largely the reason why Delta (pic above) needs the huge hump while Ohio's hump is comparatively more streamlined:

Missile dimensions are key to determining the hump. Where the missile is even shorter (like France's M51 which is only 12.0m) the hump on Triomphant is totally non-existent:

When we compare the original Agni-V tested 12 years ago to the new MIRVed version you'll see that it's actually shorter (even accounting for the blunt nose, look at the height of the upper black interstage):

This is despite the fact that if anything, the MIRVed version actually has to carry heavier payloads. There's no doubt that India's solid-fuel propulsion tech has advanced considerably over the last decade. Not to mention progress in composite stages, which reduce weight & in turn reduce amount of fuel needed.

What we're seeing in the S5's design evolution is likely a result of that progress actually.

 

[Gessler]

I also feel like the number of missiles might have gone up from 12 to 16 just from looking at the sheer length of the compartment.

Just made a post that should address this to some extent.


View: https://x.com/Parthu_Potluri/status/1862075271144468881

 

[randombully]

Project-77: An Analysis of the Indian Navy’s Nuclear Attack Submarine Program

The ‘P77’ program would encompass the construction of the Indian Navy’s first indigenously-built nuclear-powered attack submarines or SSNs. In the absence of much officially-released information, a lot is left to infer regarding what the boats built under this program would be capable of. But...

www.strategicfront.org

 

[darkflame]

https://www.thehindu.com/news/natio...ars-for-construction/article68959614.ece/amp/
The design phase of the indigenous nuclear attack submarines (SSN) will take four to five years and another five years for the construction of the first one building on the experience of the ballistic nuclear missile submarine programme (SSBN), officials in the know said.

Since it will take 4-5 years more for construction of SSN to start. 5th arihant class now makes sense, since it will the stop the line from getting idle.

 

[Fatalis]

https://www.thehindu.com/news/natio...ars-for-construction/article68959614.ece/amp/
The design phase of the indigenous nuclear attack submarines (SSN) will take four to five years and another five years for the construction of the first one building on the experience of the ballistic nuclear missile submarine programme (SSBN), officials in the know said.

Since it will take 4-5 years more for construction of SSN to start. 5th arihant class now makes sense, since it will the stop the line from getting idle.

May be the first S5 is getting built there.

 

[Gessler]

https://www.thehindu.com/news/natio...ars-for-construction/article68959614.ece/amp/
The design phase of the indigenous nuclear attack submarines (SSN) will take four to five years and another five years for the construction of the first one building on the experience of the ballistic nuclear missile submarine programme (SSBN), officials in the know said.

Since it will take 4-5 years more for construction of SSN to start. 5th arihant class now makes sense, since it will the stop the line from getting idle.

The article seems poorly researched. Just gonna rephrase what I've already said about this piece on another forum with quotes from the article:

The design and development should take four to five years, and the construction another five years, sources said. An SSN is different from SSBN but the experience of building the latter is helpful and the reactor and other specifications will be finalised considering the requirement of speed and endurance that SSNs need, the sources stated

The only country currently capable of reliably building an SSN in 5 years is the US.

The UK takes 10-11 years from keel-laying to commissioning of an Astute-class. France takes 13 years for Barracuda. If these 'sources' think we can finish it in 5 years, then it would seem they think building an SSN is the same as building an SSK. Which means these sources are probably not of the 'informed' variety.

If we are aiming for commissioning by 2036-37, then construction on the first boat HAS to start within the next 2 years. Which means design is either mostly done & dusted or at least very close to it.

The S4* is bigger and more capable than the first one, INS Arihant (S2), that is essentially a technology demonstrator developed under the Advanced Technology Vessel (ATV) programme.

S4 itself is bigger than the first two, as satellite images clearly show. This guy seems to have been sleeping under a rock for last 3 years.

The first two SSBNs share the same reactor while the S4 and S4* have an improved reactor and can carry a good number of the K-4 SLBMs, as reported by The Hindu earlier.

If at all an improved reactor is in play (which I think is likely), then it must have come online with the S3 itself, not S4.

There's a huge 8-year gap between commissioning of Arihant and Arighaat, which can explain the ordeal of certifying a new reactor configuration (because everything - power, propulsion, safety etc is downstream from the reactor), whereas S4 is expected to be commissioned by next year itself.

That timeline doesn't gel with bringing an improved reactor config online. The S3 timeline does - even if you account for ironing out any issues with the first boat.

~~

Rest of the article is just word salad to meet the quota.