Indian Nuclear Attack Submarine (Project 77) - Updates & Discussions

[Speedster1]

I was under the impression double hulls have a dual function . The first being safety , the second being sound attenuation.

Latest Russian double hull Borei-A SSBN are doubly quite than Virginia class...... 1 & a half hull Yasen-M are as quite as there western counterparts despite not using pump-jet...... Double hull being inherently noiser than single hull is a myth.

Safety, yes. Sound attenuation, not so much. Without vibration dampening, sound from within the hull (machinery spaces, etc) will radiate for miles via the outer casing. (I don't know if the rubber tiles mounted on the exterior surface are also applied to the insides.)


A lot of the hype about the Kilo, for example, being a 'black hole' was propagated by the USN to secure funding for ultra expensive designs like the Seawolf class.

If double-hulled boats were so stealthy, the West would've adopted them by now. Just like they did other Soviet/Russian innovations like IRST and HOBS WVR AAMs (R73+HMS).

Frankly why exactly are we going in for an enlarged Scorpene is beyond me when we're also negotiating & in the process of finalising the Project 75 I shortly which is for a similar class of submarines , unless of course the IN wants to compare both designs & incorporate the best features of either submarine in the said project.

For economies of scale, progressive indigenization, and maintaining mfg expertise. Type 212 C/D is a cutting-edge boat which will have a steep learning curve. We're going for TKMS' unproven AIP (over Siemens) for P-75I which is as risky as DRDO's own AIP.

Kalvari B2 will serve as testbed for an indigenous CMS, HWT, SLCM, IPMS etc that will eventually make its way onto P76. Although, NG is quoting a very high price for the 3 follow-on boats, even though the production infra is already in place at MDL.

 

[_Anonymous_]

Safety, yes. Sound attenuation, not so much. Without vibration dampening, sound from within the hull (machinery spaces, etc) will radiate for miles via the outer casing. (I don't know if the rubber tiles mounted on the exterior surface are also applied to the insides.)

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A lot of the hype about the Kilo, for example, being a 'black hole' was propagated by the USN to secure funding for ultra expensive designs like the Seawolf class.

If double-hulled boats were so stealthy, the West would've adopted them by now. Just like they did other Soviet/Russian innovations like IRST and HOBS WVR AAMs (R73+HMS).

Not necessarily. The west may follow a different design philosophy. It's not necessary that they ape every move the USSR made / Russia makes.

For example - all Russian FAs are extremely manoeuvrable agile . The west doesn't necessarily follow the same design philosophy.

The Su-57 is a good case in point . Either the Russian designers are going in for iterative development of stealth or they're calculating passive stealth with less manoeuvrability will not work in the long run what with the advances in detection & tracking technology not necessarily restricted to radars in the near to middle term future.

You'd have space based 24 x 7 space based ISR which will be common within a decade give or take 5 yrs.

For economies of scale, progressive indigenization, and maintaining mfg expertise. Type 212 C/D is a cutting-edge boat which will have a steep learning curve. We're going for TKMS' unproven AIP (over Siemens) for P-75I which is as risky as DRDO's own AIP.

Kalvari B2 will serve as testbed for an indigenous CMS, HWT, SLCM, IPMS etc that will eventually make its way onto P76. Although, NG is quoting a very high price for the 3 follow-on boats, even though the production infra is already in place at MDL.

Still doesn't answer why the IN went in for an enlarged Scorpene. A different model even if it's enlarged will call for different tooling which adds to the costs as well as time taken to build such a unit.

If the objective is to replenish stocks quickly which it is as well as not letting the lines go idle which is also a factor , it stands to reason you go in with the same design only incorporating the latest in other technologies which I've touched upon in the previous post.

 

[Speedster1]

That Type 212CD is double hulled is news to me. But I see your point.

The Su-57 is a good case in point . Either the Russian designers are going in for iterative development of stealth or they're calculating passive stealth with less manoeuvrability will not work in the long run what with the advances in detection & tracking technology not necessarily restricted to radars in the near to middle term future.

Su-57 is only the 1st gen of Russian stealth fighters. Quite understandable that they'd be conservative. The US has had a 40 year headstart over them in this arena and deep pockets to fund all kinds of exotic research.

It is also has to do with Russian warfighting doctrine. Unlike the US, Russia is not an expeditionary AF. If Ru Su-57s ever go up against the F-35 over combat, they will be backed by a very substantial A2/AD network in their own airspace. Same philosophy as the Soviets who favored mass-produced, cheaper airframes over cutting-edge tech.

Still doesn't answer why the IN went in for an enlarged Scorpene. A different model even if it's enlarged will call for different tooling which adds to the costs as well as time taken to build such a unit.

Afaik, the hull dia remains the same. The length is extended because of the AIP plug (and possibly another plug for VLS SLCM). The increase in costs in mainly because of a higher percentage of component/hardware indigenization, weapons integration, warranties.

Incidentally, negotiations for the Rafale/MRFA are on a similar trajectory. The GoI/MoD wants 60% indigenization but won't foot the bill for it.

 

[South block]

INS Chakra

 

[RISING SUN]

INS Chakra

View attachment 50323

How come such sensitive photos are getting leaked? Both men and materials?

 

[lmaoxd]

How come such sensitive photos are getting leaked? Both men and materials?

INS chakra is more of a training ship rather than a ship at combat, only in cases of extreme urgency or actual war against china or such major issues would it be put into combat. So picks of INS chakra are a lot easier to find vs the arihant class which are isnanely hard to find apart from satellite images

 

[South block]

How come such sensitive photos are getting leaked? Both men and materials?

It's a screenshot from an Indian Navy video.

 

[RISING SUN]

It's a screenshot from an Indian Navy video.

Their PR Team should have masked the critical systems and operator faces before releasing it publically.

 

[Ashwin]

Their PR Team should have masked the critical systems and operator faces before releasing it publically.

They decide what is critical, which they clearly do not think.

 

[Parthu]

Sandeep Unnithan now reports that the 6,000-ton figure for SSN is an earlier configuration. The new 190-200 MWth PWR means that the Project-77 is going to be a ~10,000 ton vessel after all. So Rajat Pandit's TOI report was right all along.

This would make it similar in size to the Akula or Yasen, though the inclusion of 12 x VLS as reported would make it more in line with Yasen's configuration. The VLS will reportedly be capable of accommodating ASBMs & Hypersonics...so most probably same size as the BrahMos UVLM.

 

[randomradio]

Sandeep Unnithan now reports that the 6,000-ton figure for SSN is an earlier configuration. The new 190-200 MWth PWR means that the Project-77 is going to be a ~10,000 ton vessel after all. So Rajat Pandit's TOI report was right all along.

This would make it similar in size to the Akula or Yasen, though the inclusion of 12 x VLS as reported would make it more in line with Yasen's configuration. The VLS will reportedly be capable of accommodating ASBMs & Hypersonics...so most probably same size as the BrahMos UVLM.

This has been known since last year, since BARC announced multiple reactor designs, including a new 200 MWe one for both S-5 and SSNs.

Even naval ships and commercial ships. 200 MWe here too. That's suitable for a PANG-class ship with 2 reactors.

A smaller 55 MWe marine reactor is also being developed.

 

[Parthu]

This has been known since last year, since BARC announced multiple reactor designs, including a new 200 MWe one for both S-5 and SSNs.

Even naval ships and commercial ships. 200 MWe here too. That's suitable for a PANG-class ship with 2 reactors.

A smaller 55 MWe marine reactor is also being developed.

The 190-200MW PWR for for S5/P77 was known for even longer. What wasn't confirmed till now is whether P77 was to be a pure SSN or an SSGN with the additional mission set brought on thanks to VLS. As a pure SSN, the 6,000-ton figure was plausible. But now that's not to be.

And it's 200 MWth. 200 MWe is impossible for submarines. That would have to mean 700+ MWth

 

[randomradio]

The 190-200MW PWR for for S5/P77 was known for even longer. What wasn't confirmed till now is whether P77 was to be a pure SSN or an SSGN with the additional mission set brought on thanks to VLS. As a pure SSN, the 6,000-ton figure was plausible. But now that's not to be.

And it's 200 MWth. 200 MWe is impossible for submarines. That would have to mean 700+ MWth

Even the 6000 DWT SSN came with VLS. But these are not strictly SSGNs anymore, which is reserved for arsenal subs like Ohio. Even the USN lists Virginia B5s with VPM as SSNs while creating a new class under SSGNs. They are switching things up here, keeping terminologies more relevant.



And yeah, 200 MWe for the ships, not subs. My bad there.

 

[Parthu]

Even the 6000 DWT SSN came with VLS.

How can we know?

As per my Twitter conversations with Sandeep, VLS was not yet confirmed as of late 2024. Same for pumpjet inclusion, wasn't yet confirmed.

My reading of it is that the new SSN program originally started off picking up where the ATV left it (from back when ATV had to be redesigned into SSBN due to strategic considerations) i.e. an Arihant without the missile compartment, and the same 83 MWth B1 PWR. But this likely never got anywhere beyond the conceptual stage as by that point, we were anticipating the 190-200 MWth B2 PWR to be ready soon.

After the B2 became viable, the first order of business would've been to simply come up with a new design centered around the new reactor, but fulfilling the same mission as before. This was likely following the 2015 CCS approval of 6 boats which were described as 6k tons back then.

But consequentially, we would have felt this limited mission set would be a waste of the B2's huge output capacity, and started adding things like a sizeable (12-pack) VLS module, alongside inclusion of other advanced technologies like a turbo-electric drive instead of mechanical reduction gearbox. These additions would have turned it from ~6,000 tons to the new 9,800 tons.

I believe this shift from 'pure SSN' to 'SSGN' is marked by the shift in program designation from Project-75A to Project-77.

It's all just my theory though.

But these are not strictly SSGNs anymore, which is reserved for arsenal subs like Ohio. Even the USN lists Virginia B5s with VPM as SSNs while creating a new class under SSGNs. They are switching things up here, keeping terminologies more relevant.

View attachment 51660

And yeah, 200 MWe for the ships, not subs. My bad there.

Yea the designations are very fluid. My reference to it as an SSGN is purely for sake of this discussion - as a way to differentiate from possible earlier configurations without VLS.

 

[babablacksheep]

How can we know?

As per my Twitter conversations with Sandeep, VLS was not yet confirmed as of late 2024. Same for pumpjet inclusion, wasn't yet confirmed.

My reading of it is that the new SSN program originally started off picking up where the ATV left it (from back when ATV had to be redesigned into SSBN due to strategic considerations) i.e. an Arihant without the missile compartment, and the same 83 MWth B1 PWR. But this likely never got anywhere beyond the conceptual stage as by that point, we were anticipating the 190-200 MWth B2 PWR to be ready soon.

After the B2 became viable, the first order of business would've been to simply come up with a new design centered around the new reactor, but fulfilling the same mission as before. This was likely following the 2015 CCS approval of 6 boats which were described as 6k tons back then.

But consequentially, we would have felt this limited mission set would be a waste of the B2's huge output capacity, and started adding things like a sizeable (12-pack) VLS module, alongside inclusion of other advanced technologies like a turbo-electric drive instead of mechanical reduction gearbox. These additions would have turned it from ~6,000 tons to the new 9,800 tons.

I believe this shift from 'pure SSN' to 'SSGN' is marked by the shift in program designation from Project-75A to Project-77.

It's all just my theory though.



Yea the designations are very fluid. My reference to it as an SSGN is purely for sake of this discussion - as a way to differentiate from possible earlier configurations without VLS.

How do we known the no. of VLS will be 12?
I think larger SSBN size tubes makes more sense, each tube holding 3-4 cruise missiles or a larger LR-ASHM sized missile.

 

[Parthu]

How do we known the no. of VLS will be 12?
I think larger SSBN size tubes makes more sense, each tube holding 3-4 cruise missiles or a larger LR-ASHM sized missile.

Watch the video in post #610. He says they'll carry "close to a dozen" ballistic missiles (though I think that's a slip of tongue, he probably meant cruise).

But the way he says it (describing them as being able to carry conventionally armed ballistic missiles & hypersonic missiles), it seems the VLS will be large. So potentially heavy missiles can be carried. I don't believe it'll be big enough for LRAShM though...unless we create a smaller booster for it.

The Project Vishnu/ER-LDHCM will anyway be carried.

 

[lmaoxd]

Watch the video in post #610. He says they'll carry "close to a dozen" ballistic missiles (though I think that's a slip of tongue, he probably meant cruise).

But the way he says it (describing them as being able to carry conventionally armed ballistic missiles & hypersonic missiles), it seems the VLS will be large. So potentially heavy missiles can be carried. I don't believe it'll be big enough for LRAShM though...unless we create a smaller booster for it.

The Project Vishnu/ER-LDHCM will anyway be carried.

LRAShM seems to be our DF17 or better version. Its mostly a shore based platform. Unless ofc they want slant launchers on the frigates or destroyers.

 

[Speedster1]

P77 is likely also being designed to match up to the PLANs new Type 095 SSN which is reportedly also in the 9000t-10000t displacement range and with design features similar the US Seawolf class.

 

[randomradio]

How can we know?

As per my Twitter conversations with Sandeep, VLS was not yet confirmed as of late 2024. Same for pumpjet inclusion, wasn't yet confirmed.

My reading of it is that the new SSN program originally started off picking up where the ATV left it (from back when ATV had to be redesigned into SSBN due to strategic considerations) i.e. an Arihant without the missile compartment, and the same 83 MWth B1 PWR. But this likely never got anywhere beyond the conceptual stage as by that point, we were anticipating the 190-200 MWth B2 PWR to be ready soon.

After the B2 became viable, the first order of business would've been to simply come up with a new design centered around the new reactor, but fulfilling the same mission as before. This was likely following the 2015 CCS approval of 6 boats which were described as 6k tons back then.

But consequentially, we would have felt this limited mission set would be a waste of the B2's huge output capacity, and started adding things like a sizeable (12-pack) VLS module, alongside inclusion of other advanced technologies like a turbo-electric drive instead of mechanical reduction gearbox. These additions would have turned it from ~6,000 tons to the new 9,800 tons.

I believe this shift from 'pure SSN' to 'SSGN' is marked by the shift in program designation from Project-75A to Project-77.

It's all just my theory though.



Yea the designations are very fluid. My reference to it as an SSGN is purely for sake of this discussion - as a way to differentiate from possible earlier configurations without VLS.

ATV was entirely centered around nukes. Work from the 1970s was centered more around creating the industry for submarines in general, starting with feasibility and initial work on reactor propulsion, missiles etc alongside building SSKs.

Then, after DRDO was established, we got the Chakra 1 and began design work on Arihant's reactor and submarine. We designed the demonstrator reactor at Kalpakkam after studying the VM-4 reactor which powered Chakra 1 and that allowed us to create the benchmarks required for the propulsion reactor for Arihant.

IN wanted SSNs first but was denied. So IN's first SSN program only began in 2017 (design stage). By then VLS was part of all future submarine designs. To that effect, the French showed off the SMX Ocean with VLS in 2014. It's quite unrealistic to expect the IN wasn't looking at VLS at that stage.

 

[FalconSlayers]

This would make it similar in size to the Akula or Yasen, though the inclusion of 12 x VLS as reported would make it more in line with Yasen's configuration. The VLS will reportedly be capable of accommodating ASBMs & Hypersonics...so most probably same size as the BrahMos UVLM.

How many Nirbhay type missiles can those VLS accommodate? If packing is 3x per VLS then it's excellent as a conventional deterrent.