Project 75I - It Begins

[maitya]

https://x.com/manupubby/status/1805078892899680314 ---> Talks advance on procuring additional Kalvari submarines. MDL in detailed discussions for Rs 35,000 crore deal with MoD. New submarines to be larger, stealthier, with more endurance. At least 60% indigenous content and 5,000 jobs to be created.
...

WTH, why there's 0 mention of the AIP term in the report ... what's all this "... more endurance ..." tamasha hien jee?

[Prem Kumar]

If the IA can screw up artillery, armor & infantry,
If the IAF can screw up the MRFA & AEW,
Why can't the IN screw up its submarine program, hain?

[Rakesh]

Yeah I call BS on that. This is essentially a new design based on the Scorpene. We'll be lucky if the development is even complete in six years. We needed these boats yesterday. First it was the insistence on VLS which delayed the whole thing and now it will be this.

Saar, MDL has yet to deliver the sixth (the Vagsheer) boat. She is undergoing sea trials. The first boat (INS Kalvari) had her steel cutting in 2006, 18 years ago. It has taken nearly 2 decades to deliver six diesel electric submarines. This is beyond pathetic.

Regardless, they should have just continued with another six Scorpenes, in the same configuration as the first batch of six. Even with all the delays, the build times had reduced as the construction of six boats got underway. At a later stage, they could have upgraded the boats. But they don't like to do easy and logical things.

Secondly, if these three Scorpenes are going to be larger and with greater endurance, what is the point of the Project 75I program? What game changing technology is there in Navantia's S-80 Class boat, that this proposed "larger" Scorpene does not have?

[Pratyush]

The increased size is a function of the installation of the AIP to the boat from the start.

DRDO AIP module IIRC is 300 tons of additional displacement.

While you are adding the AIP module to the boat. Perhaps a 12 cell VLS plug can also be added. That should be possible for under a 100 tons.

Like the Yankees have done for the block 4 Virginia.

That will be a seriously capable boat.

[srai]

India lacks continuity. Not building on what has been established after decades of effort. Instead, all is wasted in pursuit of next “big” thing that will be decades out.

[Prem Kumar]

This is a reflection of how a country's Armed Forces leadership thinks when they are not serious about war, are not students of history, have no vision for our future & are in denial about the world they live in

These are not serious people. They are where they are because the system has to promote someone to the top position. Someone like a Sundarji is an outlier who we got by chance, not by design

[vonkabra]

WTH, why there's 0 mention of the AIP term in the report ... what's all this "... more endurance ..." tamasha hien jee?

Probably it means that the new boats will have full Lithium-Ion battery configuration like what is being offered to Indonesia.

[maitya]

Yeah I call BS on that. This is essentially a new design based on the Scorpene. We'll be lucky if the development is even complete in six years. We needed these boats yesterday. First it was the insistence on VLS which delayed the whole thing and now it will be this.

Saar, MDL has yet to deliver the sixth (the Vagsheer) boat. She is undergoing sea trials. The first boat (INS Kalvari) had her steel cutting in 2006, 18 years ago. It has taken nearly 2 decades to deliver six diesel electric submarines. This is beyond pathetic.

Regardless, they should have just continued with another six Scorpenes, in the same configuration as the first batch of six. Even with all the delays, the build times had reduced as the construction of six boats got underway. At a later stage, they could have upgraded the boats. But they don't like to do easy and logical things.

Secondly, if these three Scorpenes are going to be larger and with greater endurance, what is the point of the Project 75I program? What game changing technology is there in Navantia's S-80 Class boat, that this proposed "larger" Scorpene does not have?

Rakeshji, isn't Kalvari scheduled for her first major refit next year ... and couple-of-months/maybe-an-year back, there were all these talks of retrofitting a plug-containing-AIP during that, isn't it?
What happened to that? Nothing, it seems ...

So, all these talk about "upgrading later" is just that ... vaporware.

While building more Scorpenes is valid point, but in our context, if this opportunity is not taken to shoe-horn the desi-AIP to it, it'll never get done - MoD baboons simply doesn't possess the mental faculty to fathom such build-now-quickly-upgrade later type concepts, and the services, well lesser said better it is (after all, all it requires is for a random foreign vendor to offer shiny brochures of a brand-new product, and such "upgrade" talks will be swiftly forgotten).

So another 3 boats are welcome, but needs to come with desi-AIP integrated from day one.
And, of course, they are not going to come cheap anyway (compare the price of the parent program and the price for the 3 additional programs), so this is the opportunity to give these baboons something (read AIP) to justify the "additional" spend.

[maitya]

WTH, why there's 0 mention of the AIP term in the report ... what's all this "... more endurance ..." tamasha hien jee?

Probably it means that the new boats will have full Lithium-Ion battery configuration like what is being offered to Indonesia.

Yeah, anything but something that has even an hint of self-sufficiency - as there's always real danger that a self-sufficient vendee may ignore future sales opportunities, isn't it?
Strategic partnership, my foot ...

[Rakesh]

Rakeshji, isn't Kalvari scheduled for her first major refit next year ... and couple-of-months/maybe-an-year back, there were all these talks of retrofitting a plug-containing-AIP during that, isn't it?
What happened to that? Nothing, it seems ...

So, all these talk about "upgrading later" is just that ... vaporware.

That plan is still very much on! Being a submarine, the exact timeframe of the refit is not publicly known. The plan is to refit Kalvari with the DRDO AIP plug and then the subsequent boats. But you know how things work in India. Things take their own sweet time. There is no urgency for anything. Once and whenever completed, then we will hear an announcement.

While building more Scorpenes is valid point, but in our context, if this opportunity is not taken to shoe-horn the desi-AIP to it, it'll never get done - MoD baboons simply doesn't possess the mental faculty to fathom such build-now-quickly-upgrade later type concepts, and the services, well lesser said better it is (after all, all it requires is for a random foreign vendor to offer shiny brochures of a brand-new product, and such "upgrade" talks will be swiftly forgotten).

So another 3 boats are welcome, but needs to come with desi-AIP integrated from day one. And, of course, they are not going to come cheap anyway (compare the price of the parent program and the price for the 3 additional programs), so this is the opportunity to give these baboons something (read AIP) to justify the "additional" spend.

These three boats are coming with the DRDO AIP plug. The greater endurance that the article is talking about comes from not only the boat being larger (so can carry more fuel), but also with AIP.

My hope is that once construction gets underway of these three boats, a light bulb will turn on in someone's head. So hoping that Project 75I gets cancelled, in favour of improving upon the Scorpene line. This is a far better option, than start on a whole new type i.e. Type 216 from TKMS. So something like this;

Project 75 Kalvari Class: six boats
Project 75 "Improved" Kalvari Class: three boats (which should be six IMVHO as a P-75I program)
Project 76: six boats with an increased / or fully indigenous content than the P-75I program

This penchant for jumping on to the next latest thing is seriously messed up. The Type 216 will no doubt be a great boat. But the time frame, budget overruns, construction delays do not auger well for the Indian Navy. Just like in the Tejas program, our Achilles heel lies in the engine department. The Kalvari boat have MTU diesels from Germany. The Type 216 will also have MTU diesels from Germany. Which engine will Project 76 have? This will also have MTU diesels from Germany, but MoD/Naval HQ will call the program a Model of Self Reliance!

We love assembling foreign products and calling it self reliance. I don't understand the fascination and motivation behind it, other than palms getting greased.

[TVenky]

In case of Scorpene, have we considered the impact of sensitive data hacking way back in 2016..?..

[Rakesh]

In case of Scorpene, have we considered the impact of sensitive data hacking way back in 2016..?..

Of course. Why would they be going in for three more Scorpenes, if the boats were compromised?

[basant]

This is the next awaited big ticket project. Finally cleared and the RFP should be out soon. Lets track it here. Hope it doesn't turn into another saga though in way it already kinda is...

http://idrw.org/?p=45766#more-45766

Looks like Private Shipyards are going to get a shot at this.

Was a little bored today, seek mods' forgiveness for the infraction in advance. Saw the first post of this thread. Shortly, we can celebrate its 10th anniversary and next year 15th anniversary for the principal approval of the project itself. Sadly, we seem to have lost Will (the BRFite) 5 years after cautious hope was expressed over the project.

I applaud IN for its perseverance that is submerged for almost a decade and half.

OTOH, can we have a thread for top delayed projects please?

[Aditya_V]

I think the Scorpene may be the leader, but unlike the MRFA, I think TKMS is put in so that the French Spanish Naval group agree to some of our requirements rather than acting uppity.

[Pratyush]

I think the Scorpene may be the leader, but unlike the MRFA, I think TKMS is put in so that the French Spanish Naval group agree to some of our requirements rather than acting uppity.

A fool and his money is soon parted. The Indian defence procurement people shop wearing a dunce hat. That's the only explanation for what we are seeing in our procurement process.

It doesn't matter, if the equipment is imported or manufactured in India.

[maitya]

Rakeshji, isn't Kalvari scheduled for her first major refit next year ... and couple-of-months/maybe-an-year back, there were all these talks of retrofitting a plug-containing-AIP during that, isn't it?
What happened to that? Nothing, it seems ...

So, all these talk about "upgrading later" is just that ... vaporware.

<snip>
...
Project 75 Kalvari Class: six boats
Project 75 "Improved" Kalvari Class: three boats (which should be six IMVHO as a P-75I program)
Project 75U: Upgrade Project 75 boats with AIP-plug during their major refits
Project 76: six boats with an increased / or fully indigenous content than the P-75I program plus a VLS plug
Project 76U: Upgrade the 9 Kalvari Class boats with a VLS plug
...
<snip>

There corrected for you ... seriously, how difficult is to accommodate a VLS plug especially when much larger AIP plug is considered kosher to integrate it during a major refit...

[Rakesh]

There corrected for you ... seriously, how difficult is to accommodate a VLS plug especially when much larger AIP plug is considered kosher to integrate it during a major refit...

Maitya-ji: Couple of points...

* The six Project 75 Kalvari Class will feature DRDO AIP during their refits. They will all become Project 75U

* Project 76U will be moot, as Project 76 boats will come with DRDO AIP or likely lithium-ion batteries from date of commissioning.

[Rakesh]

Was a little bored today, seek mods' forgiveness for the infraction in advance. Saw the first post of this thread. Shortly, we can celebrate its 10th anniversary and next year 15th anniversary for the principal approval of the project itself. Sadly, we seem to have lost Will (the BRFite) 5 years after cautious hope was expressed over the project.

I applaud IN for its perseverance that is submerged for almost a decade and half.

OTOH, can we have a thread for top delayed projects please?

Saar, why see the first post of this thread...when you can read the title of the thread

It Begins ----> 10 years later, it is still at that stage onlee...

[maitya]

There corrected for you ... seriously, how difficult is to accommodate a VLS plug especially when much larger AIP plug is considered kosher to integrate it during a major refit...

Maitya-ji: Couple of points...

* The six Project 75 Kalvari Class will feature DRDO AIP during their refits. They will all become Project 75U

* Project 76U will be moot, as Project 76 boats will come with DRDO AIP or likely lithium-ion batteries from date of commissioning.

Errr ... Project 76U* is about adding the VLS Plug during refits, *after* they have desi-AIP integrated and then in operation for a few years - so, 2nd Plug for the Project 75U boats (so during their 2nd refit) and 1st plug for the Project 75 "Improved" ones (so during their 1st Refit)!!

*Note - Fictitious nomenclature

[Rakesh]

Errr ... Project 76U* is about adding the VLS Plug during refits, *after* they have desi-AIP integrated and then in operation for a few years - so, 2nd Plug for the Project 75U boats (so during their 2nd refit) and 1st plug for the Project 75 "Improved" ones (so during their 1st Refit)!!

* Project 76 will come with both VLS plug (for missiles) + with new-generation, desi-AIP plug from day one. Project 76U (fictitious nomenclature) can certainly be given, post her mid-life refit (i.e. better sonar, weapons, sensors, etc).

* Project 75I (either TKMS from Germany or Navantia of Spain) will feature an AIP system from day one. The VLS plug requirement has been dropped from what I have been told. Perhaps our Admirals will get a new round of brochuritis and bring back the VLS requirement! But more than likely, such a plug will be incorporated during a midlife refit. So perhaps P-75IU?

* Project 75 (Kalvari) Class will come with AIP plug, post her refit, but there is no plan for a second plug (i.e. VLS). The Kalvari Class uses the SM-39 Exocet AShM, which is launched from her torpedo tubes. Perhaps in the future, a miniaturized BrahMos/Nirbhay could be launched from her 533mm tubes.

[SRajesh]

Rakesh
Correct me if I am wrong in my assumptions about VLS.
What is the navy Doctrine?? Being Multi Regional power projection Navy
And for that we not only need AShM capabilities but ?? also LRCM capable??
Now I dont want to infect the our Admirals with Brochure Virus but would they not naturally latch on to this new terminology and request VLS plug-ins!!
How will LRCM or proper Brahmos be fired from torpedo tubes??

[Rakesh]

VLS is a great capability to have. Your points above are valid.

See the Los Angeles Class, Virginia Class, Yasen Class, Ohio Class SSGN variant (not the SSBN variant).

These are all nuke boats, so infinite endurance unlike the SSKs. But the power projection offered is invaluable. Tremendous flexibility to military planners. Submarines are perfect for this, especially the nuclear boats. Run Silent, Run Deep.

We will get there as well with Project 75 Alpha ---> Indian SSN program. 190 MW HEU reactor with Indian-developed Sonar (new generation USHUS in the bow plus flank array and towed array sonar), Indian weapons in torpedo tubes (upgraded Varunastra) and VLS cells (BrahMos-S, Nirbhay-S), etc...

[maitya]

Errr ... Project 76U* is about adding the VLS Plug during refits, *after* they have desi-AIP integrated and then in operation for a few years - so, 2nd Plug for the Project 75U boats (so during their 2nd refit) and 1st plug for the Project 75 "Improved" ones (so during their 1st Refit)!!

* Project 76 will come with both VLS plug (for missiles) + with new-generation, desi-AIP plug from day one. Project 76U (fictitious nomenclature) can certainly be given post her mid-life refit (i.e. better sonar, weapons, sensors, etc).

* Project 75I (either TKMS from Germany or Navantia of Spain) will feature an AIP system from day one. The VLS plug requirement has been dropped from what I have been told. Perhaps our Admirals will get a new round of brochuritis and bring back the VLS requirement! But more than likely, such a plug will be incorporated during a midlife refit. So perhaps P-75IU?

* Project 75 (Kalvari) Class will come with AIP plug, post her refit, but there is no plan for a second plug (i.e. VLS). The Kalvari Class uses the SM-39 Exocet AShM, which is launched from her torpedo tubes. Perhaps in the future, a miniaturized BrahMos could be launched from her 533mm tubes.

Rakeshji, that's precisely my point (a wet-dream, actually) ... aka the 9 (6+3) Kalvari class should get a VLS plug at some point in their lifetime - just that, there's no need to hold hostage of the dev (for 3 boats) and upgrade (6 boats) programs to that requirement.
It can always come later, once the basic requirement of underwater endurance* (conventional means) is addressed, maybe in parallel to the Project 76 itself.

Till then our hope rests on BrahMos NG Production to Start in 2025, 2 New Export Deals this year program.

*PS: Whatever happened to the Li-Ion battery package (for catering to short-burst requirement) ... so AIP for slow-ops endurance requirements alongwith the Li-ion package for short-burst requirement.
Maybe that itself can be another upgrade program, via maybe another plug, after the AIP based endurance requirements have been met.

[Rakesh]

Rakeshji, that's precisely my point (a wet-dream, actually) ... aka the 9 (6+3) Kalvari class should get a VLS plug at some point in their lifetime - just that, there's no need to hold hostage of the dev (for 3 boats) and upgrade (6 boats) programs to that requirement.

It can always come later, once the basic requirement of underwater endurance* (conventional means) is addressed, maybe in parallel to the Project 76 itself.

I am not a naval engineer, but my limited mango abdul knowledge tells me that there might be a restriction to how many plugs you can add on to a SSK the size of the Scorpene Class. Buoyancy, maneuverability, maximum output of the MTU diesels onboard, among other factors will likely determine the viability of multiple plugs. A larger SSK (thus Project 75I) may have more flexibility in this arena. But P-75I is coming in from day one with an AIP built into the design. The only (future) plug will be a VLS one, unless that is also factored into the design.

Till then our hope rests on BrahMos NG Production to Start in 2025, 2 New Export Deals this year program.

The above and perhaps the NASM-MR, but from the torpedo tube onlee.

Disadvantages of a littoral SSK (Project 75, Kalvari Class) versus an ocean-going SSK (Project 75I).

*PS: Whatever happened to the Li-Ion battery package (for catering to short-burst requirement) ... so AIP for slow-ops endurance requirements along with the Li-ion package for short-burst requirement. Maybe that itself can be another upgrade program, via maybe another plug, after the AIP based endurance requirements have been met.

Saar, either AIP or lithium-ion. But you cannot have both on a single vessel. Li-ion is the technological replacement/successor to the AIP. Even if doable, the complexity to incorporate two systems - on top of the diesel engines - would make it cost prohibitive. That is not going to happen in India.

Japan built 12 Sōryū Class vessels. The 11th and 12 vessels (the Ōryū and the Tōryū respectively) switched out their AIP systems for Li-Ion batteries. The successor to the Sōryū Class - the Taigei Class - only have Li-Ion batteries. There is no AIP system on board.

A Kilo Class boat of the Indian Navy has been deputed for Li-Ion battery development and testing. How far that program is, is classified. Not revealed to the aam junta. Once everything is done, we will read a news blurb somewhere. Expect a full fledged, operational Li-Ion battery platform to come only in Project 76 though. That will be no earlier than late 2030s or early 2040s.

[maitya]

Rakeshji, that's precisely my point (a wet-dream, actually) ... aka the 9 (6+3) Kalvari class should get a VLS plug at some point in their lifetime - just that, there's no need to hold hostage of the dev (for 3 boats) and upgrade (6 boats) programs to that requirement.

It can always come later, once the basic requirement of underwater endurance* (conventional means) is addressed, maybe in parallel to the Project 76 itself.

I am not a naval engineer, but my limited mango abdul knowledge

Sirjee, if your naval engineering knowlidj is of mango Abdul level, mine would definitely lower/generic than that of the mango^2 (or is it mango^3) Abdul level.
That said and IMVVHO ...

... tells me that there might be a restriction to how many plugs you can add on to a SSK the size of the Scorpene Class. Buoyancy, maneuverability, maximum output of the MTU diesels onboard, among other factors will likely determine the viability of multiple plugs. A larger SSK (thus Project 75I) may have more flexibility in this arena. But P-75I is coming in from day one with an AIP built into the design. The only (future) plug will be a VLS one, unless that is also factored into the design.

My SDRE-Bania-Mango-Abdul buddhi is trying to make some sense out of the following, but aren't able to - pls help:

1) The Type-212/214 variants (including CD, SG, Dakar et all) are all ranging from ~1800Tons to ~2100Tons to ~2400Tons and from 56m to 65m to 70m in length - that's like ~35% weight addition and approx 25% length addition, across these variants.
Now, none of these increase should be exclusively because of the AIP plugs, I guess, as the Type-214 (at 1860Ton and 65m) came fitted with a AIP system (2 x HDW PEM fuel cell) anyway - so does 212A and the other variants CD/SG et all.

Similarly, if we look at Scorpene class the CM-2000 (non AIP) variant comes at 1565Tons and 62m, as opposed to 1870Tons and 70m of the AM-2000 (AIP) variant.

2) The DRDO AIP plug is reported to be 300Ton and less than 10% of hull length and is neutrally buoyant ... so it can't be too much different from 214 dimensions (1780tons/59m of 212 vs 2100tons/65m of 214).

Indian Navy looks forward to DRDOs Air-Independent Propulsion System for Submarines
"AIP conforms to the typical standard that its length be less than 10 percent of the hull it is intended for and is a cylindrical plug that is neutrally buoyant and probably weighs less than 300 tons"

So ballpark, with the AIP addition, the ~1600Ton (and 62m) boats are going to become ~1900 Ton (68-70m) variants - very very similar not only to the AM-2000 variants (so Kalvari class+AIP plug), but also to baseline Type-214 variants (Project 75I).

3) Comparing the Electric Propulsion units (e.g. 1 Siemens Permasyn 2.85 MW of 214) between the AIP and non-AIP variants of the respective classes, don't see much of a change either.
Assuming of course, the Diesel Engines (and their generators) doesn't have much of an impact wrt such plug-additions as it's the electric propulsion units which drives the boat underwater.
(higher number or more powerful Diesel engine/generators come into play, if the added weight is due to increase endurance requirement via more batteries)

4) So, coming back to the topic, my SDRE-bania-mango-abdul buddhi, is nagging me with this thought:
For a boat of that size (~2Ton, 70m), adding another ~100Ton plug (so ~5% tonnage) for VLS etc shouldn't be too much of an issue ... it won't be easy, but can't be impossible, isn't it?

Till then our hope rests on BrahMos NG Production to Start in 2025, 2 New Export Deals this year program.

The above and perhaps the NASM-MR, but from the torpedo tube onlee.

Disadvantages of a littoral SSK (Project 75, Kalvari Class) versus an ocean-going SSK (Project 75I).

I think and IMVVHO, with the AIP plug addition, the Kalvari class will transform to an ocean-going SSK - doubt any Project 75I boat would be able to offer any significant advantages over them.
So having or not-having the VLS plug will be the differentiator between them.

Between, and again my SDRE-bania-mango-Abdul mand-buddhi, is nagging me with:
There'll a world of difference wrt capability addition via Brahmos-NG (from 533mm torpedo tubes) compared to that of the extended-range Brahmos equipped VLS system.

So if we are paying thru our nose, like $1.4B for 3 boats, we might as well aim for proper ocean-going capability, isn't it.

Littoral waters be left for the Shishumar and Kilo-class etc, utilizing Brahmos-NG (from their torpedo tubes).

*PS: Whatever happened to the Li-Ion battery package (for catering to short-burst requirement) ... so AIP for slow-ops endurance requirements along with the Li-ion package for short-burst requirement. Maybe that itself can be another upgrade program, via maybe another plug, after the AIP based endurance requirements have been met.

Saar, either AIP or lithium-ion. But you cannot have both on a single vessel. Li-ion is the technological replacement/successor to the AIP. Even if doable, the complexity to incorporate two systems - on top of the diesel engines - would make it cost prohibitive. That is not going to happen in India.

Japan built 12 Sōryū Class vessels. The 11th and 12 vessels (the Ōryū and the Tōryū respectively) switched out their AIP systems for Li-Ion batteries. The successor to the Sōryū Class - the Taigei Class - only have Li-Ion batteries. There is no AIP system on board.

A Kilo Class boat of the Indian Navy has been deputed for Li-Ion battery development and testing. How far that program is, is classified. Not revealed to the aam junta. Once everything is done, we will read a news blurb somewhere. Expect a full fledged, operational Li-Ion battery platform to come only in Project 76 though. That will be no earlier than late 2030s or early 2040s.

Ummm, I think there's a confusion somewhere - whilst people talk of Lithium-ion battery ("LIB") etc (in the Submarine propulsion context), they mostly forget that there are essentially two different design/implementation types, there-in:
1) One is via replacing the existing Lead-Acid batteries ("LAB") with the LIB units - there are several benefits that accrue, including incremental addition (but nothing like game-changing etc when done in conjunction with an Fuel-Cell-based-AIP ("FCAIP") unit in place) to underwater endurance etc.
For example,

Hanwha Defense Li-ion batteries reportedly provide 160% more endurance (longer output) at economic speed and 300% more endurance at maximum speed

So for a non-FCAIP boat with it's LAB replaced with LIB ones, would mean a few more days of underwater endurance - compared to what it could achieve via it's Diesel-engine-charged-Lead-Acid-battery units of a few days. After which, in both cases, it requires to surface (or snorkel) and run it's diesel generators to recharge the batteries (either LAB or LIB).
(Do note max speed endurances are exponentially low compared to economic speed endurance, but these figures are normally classified, so no point in speculating wrt them).

For Project-75 new builds, the French has proposed this, IMVHO - i.e. replace the existing LAB units with the LIB ones, whilst retaining the FCAIP system in the plug.
This is same as in the Oryu and Toryu units* (the last two units) of the Soryu class (though, do note that, the Soryu class boats are AIP types but not FCAIP types).
So for both, the underwater endurance for both at economic speed mode (and also the maximum-speed/dash-speed mode) will certainly increase by few more days, but the game-changing underwater endurance increment aspects, in terms of multiple-weeks altogether, is still via the FCAIP mode.

For other indigenous-programs like that for the Kilo Class (without any form of AIP), it's a simple replacement of the LAB batteries with LIB. So here also, there should be incremental under water endurance capability enhancement, in terms of a few days more - but never in the range of weeks altogether underwater, that normally a FCAIP-system would bring-in.


2) But the other, and the true game-changing ones, are where the entire FCAIP-unit itself is replaced with LIB battery units i.e. the plug remains, but is stashed with LIB units (or entirely new/enlarged build to provide for more Li-ion units).
The Soryu class successor (Taigei class) is an example of this approach, you may refer to their displacements, to appreciate the scale of exclusive LIB usage.
Here of course, depending upon the amount of LIB units built-in/stashed, the underwater endurance (like in those two Soryu class boats) should be quite a bit more than a FCAIP+LIB unit equipped (like upgraded Kalvari class) ones.

*PS: There's some confusion if the last 2 Soryu class are exclusive-LIB platforms (like the successor, Taigei class) or are Sterling-AIP+MIB platforms.

[Pratyush]

https://www.navalnews.com/naval-news/20 ... submarine/

According to this page, the last 2 Soryu class subs are equipped with lithium ion batteries.

The JMSDF said that the Taigei-class boat is all equipped with lithium-ion batteries in place of lead-acid ones, just like the final two Soryu-class boats for the JMSDF: Oryu (SS 511) and Toryu (SS 512).

It's still not clear, if the lithium ion battery has been replaced by sterling engine on those boats.

[Pratyush]

According to this post from Eurasian Naval Insights. PLAN is working on a nuclear tea kettle powered submarine, with a displacement of under 3,000 tons. The USSR had a project boat that was contemporary with the original Kilo class using a similar power plant.

China's Type 041 Mini Nuclear Attack Sub is Unlike Any Other Submarines

[Rakesh]

1) The Type-212/214 variants (including CD, SG, Dakar et all) are all ranging from ~1800Tons to ~2100Tons to ~2400Tons and from 56m to 65m to 70m in length - that's like ~35% weight addition and approx 25% length addition, across these variants.
Now, none of these increase should be exclusively because of the AIP plugs, I guess, as the Type-214 (at 1860Ton and 65m) came fitted with a AIP system (2 x HDW PEM fuel cell) anyway - so does 212A and the other variants CD/SG et all.

1) The Type 212CD Class were designed with AIP on the drawing board and were commissioned into the German and Italian navies as such. They use Siemens' PEM fuel cells + a MTU diesel engine that powers the propeller. But this AIP system is not a plug, that was added on some later date.

2) The Type 218SG uses fuel cells to charge lithium ion batteries. Again, designed from day one as such. They are not add-on plugs.

3) The Dolphin-I does not have an AIP system. The Dolphin-II uses an AIP system, similar to what is found on the Type 212CD. Nothing is known about the upcoming Dakar Class. And seeing how paranoid the Israelis are, expect little to no info.

4) All the Type 214 boats (operated by Greece, South Korea, Portugal and soon Turkey) all use fuel cells + a MTU diesel engine. Similar setup, as on the Type 212CD. Again, they are not add-on plugs.

Similarly, if we look at Scorpene class the CM-2000 (non AIP) variant comes at 1565Tons and 62m, as opposed to 1870Tons and 70m of the AM-2000 (AIP) variant.

Saar, how many countries that purchased the Scorpene, operate the AM-2000 variant? The Chileans, Malaysians and the Brazilians all use the CM-2000 variant, which has a diesel engine + an electric motor. That's it. None of them want to operate the MESMA AIP, despite the benefits of an AIP system.

The Indian navy also uses the CM-2000 variant and our reason for not selecting the AM-2000 is obvious, because the Pakistan Navy uses the MESMA AIP on their Agosta 90B boats.

I do not known of a single foreign customer - that operates the Scorpene - that uses the AM-2000 variant. And the French do not use diesel-electric boats in their own navy.

2) The DRDO AIP plug is reported to be 300Ton and less than 10% of hull length and is neutrally buoyant ... so it can't be too much different from 214 dimensions (1780tons/59m of 212 vs 2100tons/65m of 214).

Indian Navy looks forward to DRDOs Air-Independent Propulsion System for Submarines
"AIP conforms to the typical standard that its length be less than 10 percent of the hull it is intended for and is a cylindrical plug that is neutrally buoyant and probably weighs less than 300 tons"

So ballpark, with the AIP addition, the ~1600Ton (and 62m) boats are going to become ~1900 Ton (68-70m) variants - very very similar not only to the AM-2000 variants (so Kalvari class+AIP plug), but also to baseline Type-214 variants (Project 75I).

3) Comparing the Electric Propulsion units (e.g. 1 Siemens Permasyn 2.85 MW of 214) between the AIP and non-AIP variants of the respective classes, don't see much of a change either.

Assuming of course, the Diesel Engines (and their generators) doesn't have much of an impact wrt such plug-additions as it's the electric propulsion units which drives the boat underwater.

That is a very big assumption Saar

Our desi jugaad is well known and if we could figure out a way to add multiple plugs (AIP, VLS, Li-Ion Battery, etc) on a boat the size of the Scorpene...it would have been done by now or at least thought about.

Your own point below is where I believe the challenge lies....

(higher number or more powerful Diesel engine/generators come into play, if the added weight is due to increase endurance requirement via more batteries).

When we start looking at adding multiple plugs on the Kalvari Class, we will have to look at more powerful diesel engines/generators. At that stage, it boils down to;

1) Cost Effectiveness.
2) Maintenance.

Even if technically doable (and that is a big IF), in a country like India...this will likely not even pass financial sanction. Swapping out the diesel engine is a significant change to a SSK boat. I don't know of any SSK boat that underwent such a nip-tuck, perhaps you might. But is it really worth doing that *OR* would the better path be to build a much larger boat with an AIP system *OR* a Li-Ion battery system *PLUS* a VLS cell? And all of this matched with a diesel engine that can handle the weight and provide the performance desired?

For a boat of that size (~2Ton, 70m), adding another ~100Ton plug (so ~5% tonnage) for VLS etc shouldn't be too much of an issue ... it won't be easy, but can't be impossible, isn't it?

Re-inventing the wheel is not something the Indian Navy has time to do, considering the pitiful condition their submarine fleet is in. An AIP plug for the Kalvari Class makes sense and launching missiles from the torpedo tubes (presently SM-39 Exocet and perhaps BrahMos-S or Nirbhay-S in the future) should be sufficient no? What does it matter, if you get slapped on the face with the right hand or the left hand?

Kalvari class will transform to an ocean-going SSK - doubt any Project 75I boat would be able to offer any significant advantages over them. So having or not-having the VLS plug will be the differentiator between them.

Saar, even with DRDO's AIP plug, the Kalvari Class (and even the upcoming P-75I Class) will remain in the IOR onlee. It will go deeper into the IOR, than currently with the Kalvari, Sindhugosh and Shishumar Classes. But with a nuclear boat (SSN), you can get out of the IOR completely. Your ToS is significantly longer in an SSN. Ocean going SSK is a marketing term used by Naval Group, TKMS, Saab, etc to sell diesel electric boats to customers that cannot afford a nuclear powered submarine fleet.

For India, both are required. We need the SSK to protect India's littorals. And we need the SSN for power projection and SSBN escort. An SSK (even with AIP or lithium ion batteries) cannot do this. Why do you think the Aussies walked out of the Shortfin Barracuda Class program?

There'll a world of difference wrt capability addition via Brahmos-NG (from 533mm torpedo tubes)[/color] compared to that of the extended-range Brahmos equipped VLS system.

Indeed. But even if you take the lowest-range BrahMos variant out there i.e. 290 km and cut that range by 50% (due to missile being launched from the torpedo tube), you will get 145 km. And if I further reduce that 145 km, to a mere 100+ km....it will still be a world of a difference better than the 50+ km range of the SM-39 Exocet.

So if we are paying thru our nose, like $1.4B for 3 boats, we might as well aim for proper ocean-going capability, isn't it.

The better path would be to scrap the P-75I contest altogether and go in for six (instead of three) more Scorpenes, with them being larger and with greater endurance. And incorporate DRDO's AIP system along with a VLS cell and a more powerful diesel engine to provide the desired output. That is the better option. But to tinker with the six Kalvari boats that we have now, would not be advisable. By all means, do an AIP plug for greater endurance. But I don't see the viability of a VLS plug or a lithium-ion battery plug. Perhaps in the future, we can swap out the AIP plug on the Kalvari Class for a lithium-ion battery plug.

Littoral waters be left for the Shishumar and Kilo-class etc, utilizing Brahmos-NG (from their torpedo tubes).

Shishumar and Sindhugosh Class will be out by the next decade. Littorals will stay forever. This problem will get negated once the boats in the SSN program (Project 75 Alpha) start entering service. Till then, the SSK will be required for the littoral waters.

Ummm, I think there's a confusion somewhere - whilst people talk of Lithium-ion battery ("LIB") etc (in the Submarine propulsion context), they mostly forget that there are essentially two different design/implementation types, there-in:
1) One is via replacing the existing Lead-Acid batteries ("LAB") with the LIB units - there are several benefits that accrue, including incremental addition (but nothing like game-changing etc when done in conjunction with an Fuel-Cell-based-AIP ("FCAIP") unit in place) to underwater endurance etc.
For example,

So for a non-FCAIP boat with it's LAB replaced with LIB ones, would mean a few more days of underwater endurance - compared to what it could achieve via it's Diesel-engine-charged-Lead-Acid-battery units of a few days. After which, in both cases, it requires to surface (or snorkel) and run it's diesel generators to recharge the batteries (either LAB or LIB).
(Do note max speed endurances are exponentially low compared to economic speed endurance, but these figures are normally classified, so no point in speculating wrt them).

For Project-75 new builds, the French has proposed this, IMVHO - i.e. replace the existing LAB units with the LIB ones, whilst retaining the FCAIP system in the plug.

This is the configuration on the Type 218SG, known an Invincible Class. There is an AIP system onboard to charge the lithium-ion batteries. They do not have lead acid batteries, as in the Sindhugosh Class.

This is same as in the Oryu and Toryu units*[/b] (the last two units) of the Soryu class (though, do note that, the Soryu class boats are AIP types but not FCAIP types).

No Saar. That is not correct. The Ōryū and Tōryū do not use the Stirling AIP system. It is solely lithium ion batteries only + diesel engine.

It has been well documented that the Ōryū and Tōryū do not use the AIP system like on the earlier Sōryū Class of vessels. If you have info that states otherwise, I would love to read it. In fact, this lithium-ion battery system on these two vessels has been satisfactory enough for the Japanese Navy to launch an entirely new class of SSK, just with this Li-ion system on-board + a diesel engine.

2) But the other, and the true game-changing ones, are where the entire FCAIP-unit itself is replaced with LIB battery units i.e. the plug remains, but is stashed with LIB units (or entirely new/enlarged build to provide for more Li-ion units).

The Soryu class successor (Taigei class) is an example of this approach, you may refer to their displacements, to appreciate the scale of exclusive LIB usage. Here of course, depending upon the amount of LIB units built-in/stashed, the underwater endurance (like in those two Soryu class boats) should be quite a bit more than a FCAIP+LIB unit equipped (like upgraded Kalvari class) ones.

The Ōryū and Tōryū use this true game-changing system

*PS: There's some confusion if the last 2 Soryu class are exclusive-LIB platforms (like the successor, Taigei class) or are Sterling-AIP+MIB platforms.

There is no confusion Saar. All clear onlee.

I have yet to come across a single SSK that uses an AIP system plus an exclusive li-ion battery system and with a diesel engine on board + a VLS cell to boot. But I am willing to be corrected on this.VLS

[fanne]

Few of the things that I have learned by going through 100s of hours of youtube and google (SI sutton and others)

1. You will not find any concrete info on how long a sub can remain underwater on full acid battery charge, but it is alluded it is 3 days.
2. It has to then surface, run the diesel engine again and fully charge the battery, this takes few hours (few less than say a night). You can charge in the night time.
3. AIP typically keeps a sub at 'hotel consumption' submerged for 3 weeks (21 days). They produce very less power, sufficient only for what is needed.
4. While submerged, the sub is typically in 'hotel' mode, what is meant is, it is cruising at 1-3 knots, basic life support are on and most combat system are on.
5. If acid batteries are used to dash, typically they will not last more than 2-3 hours.
6. LI-ION batteries typically hold 2x to 7x more power than lead acid batteries. They can also be charged faster and all of 100% of the charge can be used.
7. If a sub has to dash, acid battery take time to spool up, while with Li ION battery it is instantaneous
8.The German 212 sub has endurance of 79 days. That means it can do 21 on AIP and rest 58 on diesel charging lead acid every 3 days - approx 20 charges in 79 days.
9. I do not know if you replace 300 tonnes of AIP with 300 tonnes of Li-ion battery(real battery would be less, as other equipment, safety features etc will take-up space and weight), fully charge can they provide more than 21 days of hotel load? Looks like the answer is yes, that's why AIP is not there on recent Japanese Subs. The Li-Ion battery provide some advantages over AIP, you can use all o it and perhaps gain 10-40 hours of dash. When charging, if in friendly/neutral zone, you can run the generator longer and charge all of it (in theory).

[Rakesh]

@ Maitya-ji: See the tweet below...

https://x.com/IndoPac_Info/status/17131 ... 95991?s=20 ---> France Offers New ‘Scorpene Evolved’ Li-Ion Submarine To Indonesia.

In its latest proposal to the Indonesian Navy, France's Naval Group is proposing a new variant of its Scorpene submarine featuring Lithium-Ion battery technology. French shipbuilder Naval Group has recently updated its Scorpene submarine proposal to Indonesia. Dubbed ‘Scorpene Evolved’, the submarine’s propulsion system will be installed with a full Lithium-Ion Batteries (LIBs) configuration, thus giving it the longest endurance of any other variant in the Scorpene family. In February 2022, the two countries already signed a Memorandum of Understanding (MoU) for two locally-made Scorpene submarines.

According to official sources, thanks to the full LIBs configuration, the Scorpene Evolved will have a total endurance of 80 days (with 78 of those submerged), an operational range of more than 8,000 nautical miles, a lower indiscretion rate, and maintain top speed longer. This can be achieved because LIBs can store and deliver more energy with shorter charging times than lead-acid batteries. Full LIBs submarines are also selected because the Indonesian Navy (TNI AL) will find it easier and less expensive to maintain and operate them compared with AIP submarines which will require it to build complex offshore facilities to resupply the system since it is not possible to resupply an AIP system at sea. Extra training for submariners and other personnel who will be involved in resupplying an AIP system will also be needed.

[maitya]

Few of the things that I have learned by going through 100s of hours of youtube and google (SI sutton and others)

1. You will not find any concrete info on how long a sub can remain underwater on full acid battery charge, but it is alluded it is 3 days.
2. It has to then surface, run the diesel engine again and fully charge the battery, this takes few hours (few less than say a night). You can charge in the night time.
3. AIP typically keeps a sub at 'hotel consumption' submerged for 3 weeks (21 days). They produce very less power, sufficient only for what is needed.
4. While submerged, the sub is typically in 'hotel' mode, what is meant is, it is cruising at 1-3 knots, basic life support are on and most combat system are on.
5. If acid batteries are used to dash, typically they will not last more than 2-3 hours.
6. LI-ION batteries typically hold 2x to 7x more power than lead acid batteries. They can also be charged faster and all of 100% of the charge can be used.
7. If a sub has to dash, acid battery take time to spool up, while with Li ION battery it is instantaneous
8.The German 212 sub has endurance of 79 days. That means it can do 21 on AIP and rest 58 on diesel charging lead acid every 3 days - approx 20 charges in 79 days.
9. I do not know if you replace 300 tonnes of AIP with 300 tonnes of Li-ion battery(real battery would be less, as other equipment, safety features etc will take-up space and weight), fully charge can they provide more than 21 days of hotel load? Looks like the answer is yes, that's why AIP is not there on recent Japanese Subs. The Li-Ion battery provide some advantages over AIP, you can use all o it and perhaps gain 10-40 hours of dash. When charging, if in friendly/neutral zone, you can run the generator longer and charge all of it (in theory).

Brilliant Summary Fanneji ... reposting in full, with some highlights, for ref etc (pls don't mind).

Yes, that's the reason am asking for FCAIP plug to start with - VLS plug can come later.
i.e. the 3 new-built boats needs to have FCAIP built-in and the existing (CM-2000 variants) needs to get them via the 300-tonne plug (during their 1st refit).

This should give a very decent underwater endurance (of say 2+ weeks), in a weight/displacement range of 2000-2100Ton (and 68-70m Length) boats.
Nothing very spectacular, and even maybe just-enough to venture out of the BoB and the AS into the "oceans", but maybe by not very much thereafter.

Now if the French are offering (of course for a price, maybe quite steep as well), LIB solution as a replacement of the existing LAB, let's go for it as well, during this build/refit programs, itself.
If LAB-replaced-by-LIB is implemented, then the underwater endurance levels, with one or two dash-scenarios factored in, would still continue to be decent - and that's about it.
The aim is *NOT* to have the super-duper LIB-only AIP system, which by the way, would demand >3000T platforms etc - for the Kalvari class we should be happy with 2.0-2.2K T boat solutions.


For the Kalvari class, the only additional plug that can be thought of, is that of the VLS plug (another 100 T), but there's no point in wasting time going around in circles and waiting for approvals etc - let's get the FCAIP based diesel-electric boats (with decent endurance capability) in the 2K T class first.

This VLS-plug allows them to acquire force-multiplier capability of a *limited* long-range sea-denial ability - albeit in a very limited mode.
It'll never be in the same league of the SSNs, but that's not being asked for anyway.

One of the points people forget is: How on earth would a 9m Brahmos-ER be fitted in the hull of boats of 7.0-7.5m draft?
Answer is actually already there - the VLS cells are carried in sails (instead of purely in hulls) as in the Dakar Class (very very little info) or the old Project 611 submarines. Yes the sails will have to enlarged a bit (part of the plug), but should be doable.

Will it be a game changer - certainly not!!
Such plugs will max allow what 2 or max 4 VLS tubes, not even close to what the much larger SSNs (minm 3K T+) boasts of. But it still provides unmatched long range (500-800Km) offensive ability, albeit in limited numbers - and such a capability is complimented with the torpedo-tube-launched Brahmos-NG (250-300Km range) type solutions, giving it a very decent overall sea-denial capability.

Betw, and at the same vein, why would such a platform need a Land-attack LRCM type capability? Maybe for some situations/scenarios wrt the western neighbor ....

[Added Later]
Where does all these, leave Project-75I solutions, no clue really ...

[drnayar]

A mini nuclear plant would be the ultimate AIP i guess !

[Rakesh]

Saar, even with DRDO's AIP plug, the Kalvari Class (and even the upcoming P-75I Class) will remain in the IOR onlee. It will go deeper into the IOR, than currently with the Kalvari, Sindhugosh and Shishumar Classes. But with a nuclear boat (SSN), you can get out of the IOR completely. Your ToS is significantly longer in an SSN. Ocean going SSK is a marketing term used by Naval Group, TKMS, Saab, etc to sell diesel electric boats to customers that cannot afford a nuclear powered submarine fleet.

For India, both are required. We need the SSK to protect India's littorals. And we need the SSN for power projection and SSBN escort. An SSK (even with AIP or lithium ion batteries) cannot do this. Why do you think the Aussies walked out of the Shortfin Barracuda Class program?

The largest SSK that I know of was the Attack Class (Shortfin Barracuda) submarine ---> https://en.wikipedia.org/wiki/Attack-class_submarine . She had a 4,500 ton surface displacement. Just imagine what the submerged displacement would be. Wiki Chacha states that the Attack Class SSK had an endurance of 80 days. This proposed boat was the future Australian SSK to replace their current Collins Class boats. The Aussies soon realized the shortcomings of the Attack Class, in relation to the investment being made and the utility they offered vs a SSN.

ToS (Time on Station) for SSKs are rarely - if ever - mentioned, but that is where the real performance of a submarine lies. Below is the reality of a SSK versus a SSN. The SSN can also easily outrun a SSK. In all the Indo-US naval exercises, in where our Kilo Class boats were (theoretically) blowing the Los Angeles and Virginia Class SSNs out of the water, is because the parameters of those exercises were set in a manner for the US SSN boats to hunt down a SSK. But this is where the SSK shines. She is usually an opportunistic hunter killer i.e. waits for its target to enter into an disadvantageous position to fire the kill shot, so guard the entrances to any of the straits on India's eastern seaboard and wait for a Chinese naval flotilla. But no SSK has the speed or the range to match a SSN. A wise and prudent SSN boat commander will employ tactics to avoid this.

But this in *NO WAY* means that SSKs have no value for the Indian Navy. They are absolutely required for India's littorals and for other missions deemed necessary by India's military planners. But the Indian Navy has to get boats undetected, right into China's backyard i.e. South China Sea. That is vital in conflict and in peacetime. The PLAN needs to know that India is right there. But for this you need a SSN. No two ways about it.

Does anyone remember the USS Connecticut incident that occurred on 02 October 2021? Google it. Makes for very interesting reading. if there is anything that gives Xi and his ChiCom minions sleepless nights over Taiwan, it is the US Navy's sub fleet. At any given point in time, there are a number of USN boats sailing right in China's backyard. The British are also there, with their Astute Class boats and soon the Aussies will join in by the next decade. India needs to do the same. Give the ChiComs a moment of pause.

https://twitter.com/TheBaseLeg/status/1 ... 40384?s=20 ---> Follow @EvanLaksmana for the Indonesian take on AUKUS, from where he also linked this map that also shows why Australia is seeking an East Coast base for its SSNs.

[fanne]

I was hesitant to write about why does navy need VLS tubes in its sub, lest it starts a flame war. But since others are also questioning, let me take that thought process further.

1) You need VLS or sub based missiles to fire new clear detergent, but that is taken care by Arihant and her sister boats
2) The best way for IN (or even any Indian forces - including rocket/missile force) to attack costal china (say Beijing) will be a Sub - New Clear or conventional. I don't think IN will ever have enough muscles to sail a naval ship, defeat all of PLAN and attack their ports, sub nests and cities. There is a possibility that SU30MKI, with limited load and multiple refueling can reach there.This is one of the very strong use cases for IN to have VLS sub.
2b) SSN are best for this task, but let's just discuss SSK for now.
3) for attacking TSP, (Gwadar, Karachi is within gautham range from India), or other western hostiles like say Qatar, or some ports in east Africa where perhaps PLAN is regrouping, we have muscle to use Naval Ships (with missile) and other assets, don't need VLS Sub
4) However even to reach South China Sea or China proper, before your sub needs VLS, It needs a superb AIP/LIB. SSK were Soviet response to Overwhelming USN dominance during cold war. It is like a sniper, you have to account for it else you risk losing your capital ships. It ties up you resources (ships, planes, personnel), slows you down etc.etc.
5) I think we can easily add some 12 subs for now without VLS (if that is somehow slowing down the advance) to hinder PLAN and other taller than mountain, sweeter than honey friends if ever the need comes to that.
6) Then go for SSK with VLS. But my feeling is, in next 5 to 7 years we will have our first SSN (hopefully with VLS, the program for 6 sub was announced couple of years ago). We should plan for VLS SSK, but not at the cost of LIB/AIP SSk (without VLS). We are making good to have enemy of must have

[Rakesh]

Let us shatter the myth that a torpedo tube launched cruise missile will suffer range deficiency versus being launched vertically

Tomahawk
https://missilethreat.csis.org/missile/tomahawk/
23 April 2024

The Block IV TLAM-E is the newest upgrade to the Tomahawk series. The missile can be rerouted in-flight to either preplanned or new targets. Furthermore, the missile has a faster launch timeline and a loiter capability that, along with its electro-optic sensor, allows it to provide real-time damage assessment of previous strikes. The Block IV TLAM-E has a range of 900 nautical miles or 1,600 km. it carries a 1,000 lb. unitary warhead.16 The Block IV is the only Tomahawk variant that is still manufactured. Remaining Tomahawk missiles of other variations will be converted to the Block IV capability.

Tomahawk Long-Range Cruise Missile
https://en.wikipedia.org/wiki/Tomahawk_(missile)

Raytheon was awarded a $346m production contract for 473 Tomahawk Block IV cruise missiles in March 2006. The contract includes 65 submarine torpedo tube-launched missiles for the Royal Navy. The Block IV entered service with the Royal Navy in March 2008.

And below is from Raytheon's official website, the manufacturer of the Tomahawk missile...
https://www.rtx.com/raytheon/what-we-do ... se-missile

The Tomahawk cruise missile is a precision weapon that launches from ships, submarines, and ground launchers and can strike targets precisely from 1,000 miles away, even in heavily defended airspace.

And just to remove any ambiguity (because the above links states only "submarines" and does not mention "torpedo tube" specifically) about the range of the Block IV being reduced, due to missile being launched from the torpedo tube...see this link from the official website of the US Navy. 635 nautical miles (nearly 1,200 km) was successfully achieved, way back in 2007. Imagine what the range could be now....17 years later, with Block V.

Submarine-launched Tomahawk IV flight test a success
https://www.navair.navy.mil/node/9226
29 March 2007

Launched from the Los Angeles-Class attack submarine, USS Pasadena (SSN-752), underway in the Naval Air Systems Command Pacific Ocean Sea Range at Pt. Mugu, the missile transitioned to cruise flight and flew a satellite-guided 635-nautical mile test flight to the NAVAIR Land Range at the NAVAIR Weapons Division, China Lake, Calif.

“Like the Block III missile, the Block IV Torpedo Tube Launch missile is an all-weather, highly reliable and survivable cruise missile that can be launched from submarines,” McQueen added. “The redesign brings improvements to missile navigation, guidance, and communications subsystems.”

Photo 2 - The first test of a submarine torpedo tube-launched Tomahawk Block IV cruise missile is shown immediately prior to impact on March 26.

P.S. Waiting for someone to point out that 635 nautical miles is < than the advertised 900 nautical miles of the Block IV variant

So Fake News!

[SRajesh]

Rakesh,

Then the question is VLS for conventional sub a bit of an overkill given that there is much testing and tested cruise missile firing capabilities via the torpedo tubes.

And the VLS will be restricted only to Nuclear Subs going forward!!

Should we be reconfiguring our production/testing of some missiles and future ones to be fit for tube firing? And the regular ones for Nuclear VLS!!

[Pratyush]

One way or the other the answer is not clear cut. A submarine is a series of compromises.

Shooting cruise missiles from torpedo tubes reduces the availability of torpedoes on the torpedo racks of the submarine.

Shooting cruise missiles from VLS adds displacement, That in turn results in a requirement for a more powerful propulsion plant.

[srin]

One advantage of VLS is that you can fire large diameter missiles that don't fit into 533mm tubes.

My guess is that with Nirbhay delayed, the Navy had no choice but to go for Brahmos.

Though, it might have been easier to go for 650mm tubes rather than VLS.

[maitya]

The range of a submarine-launched missile is direct consequence of dimensions that the firing-solution (torpedo tube or VLS cells) allows it for.
A Brahmos-ER (with 8.4m L x 0.6m Dia) won't fit in the 533mm torpedo tubes of our existing Diesel-Electric class submarines ...

But if we are able to replace these existing 533mm torpedo tubes with 0.6m Dia torpedo tubes (like for say in the Dolphin or Dakar class, forgot which one or both), then it would again be possible to consider ER type missiles (of course the length would also need to be considered).

But once it does (fit), then the ranges (for the same missile) should be very similar to that launched from a VLS cell etc - I don't know for sure, and gurus can correct me, but the underwater firing solutions (either hot or cold launch) won't be too different for either of them.

But since changing torpedo tubes etc is going to be difficult (they still need to be able to fire the torpedoes for which they are there in the first place), so a smaller (and less ranged) version called Brahmos-NG (with 6m L x 0.5m Dia) has been envisioned.
Yes, granted that mere change in diameter doesn't *linearly* impact the range etc (as there are myriad of other factors/parameters that can always be improved upon etc) but an impact to the range, though not proportionate, is no doubt going to be there.

So net-net, Brahmos-NG can be fired from the 533mm torpedo tubes, albeit to it's smaller (relatively) ranges - compared to, say a VLS fired Brahmos-ER which would definitely boast a much higher range.

Question is, how serious are we about acquiring this extended-range offensive capability - and even if we are, what is the feasibility of it fitting such a solution to our existing and near-future platforms.

A 9m missile VLS can't and won't fit in a hull of draft of 6-7m ...
Yes, there are solutions like humps (which can be built-in via a plug) to the hull, but that will bring-in it's own consequences/drawbacks e.g. stealth aspect. However, a hunter-killer's strength is it's dash-speed (unlike stealth for the SSBNs), but that doesn't mean the stealth aspect can be ignored completely.

So if such a VLS solution is required, then either go for a 3-4K Ton brand new platform (that will allow for a bigger-height/draft hull) or go for a VLS plug with a hump (to the hull) or better go for a limited-number of VLS tubes in the sail itself solution (which can also come in form of a plug - gave examples in the prev post).

Now, for our Kalvari class, the plug solution (either as a hump or a sail-enlarging one) is there - integrating a ~100Ton plug to 2-2.2K Ton boat, shouldn't be too much of an challenge/issue for us, and shouldn't require changing the Electrical Motor etc (as the battery capacity etc shouldn't require changing, just for this VLS plug addition).
However, given our procurement lifecycle and decision-making ability etc, it'll be suicidal to tie this aspect (VLS plug) to the FCAIP plug addition initiative and delay the already-dangerously-delayed initiative.

So, it's better go for the FCAIP plug solution first, and then later, once all the 9 boats have been equipped with the FCAIP capability, these VLS-plug etc can be thought about.

For Project-75I etc, no clue what the thought process is ... a VLS requirement was initially there (no idea it was for allowing 9m or 6m missile classes), but may have now got dropped. Maybe due to, adding VLS capability would have made them to 3.5K-4K Ton boats, which Navy may have thought would make the program unviable from cost, timeline and risk perspectives.

PS: Anybody knows how come Amur-1650 is claiming to fit Brahmos is VLS mode in the hull itself - I mean to me, a ~1650Ton boat seems to be too small to fit such a huge missile VLS system. Or is it, another Brahmos-NG type missile that they are talking about?

[Pratyush]

More than the range of the missiles. We need to start thinking about the robustness of the kill chain for whole system.