Indian Nuclear Submarines -3

[YashG]

Worthwhile read.

https://www.newsweek.com/2023/05/05/exc ... 95014.html

Exclusive: Navy Will Spend $200 Billion—Equal to Ukraine's GDP—on Subs It Barely Uses

US has been living on debt - its debt to GDP ratio is huge. Basically US has no money to spend on Ukraine and Its own Defence - atleast not in the quantum it does. It is just taking debt to do it.

[Pratyush]

The SSK has a 20-30 feet advantage for minimum depths. When we speak littoral waters, literally speaking it is where sunlight can reach the ocean floor at about 40-100 feet depth? This will be within a few miles from the shore. Which submariner would want to play this game? The continental shelf extends about 20-80 miles from shore, IOW <1000 ft depths. The SSN loses its higher diving depth advantage within the continental shelf. The question is, would we want to lure a PLAN sub into this zone without much challenge? There are other assets to protect this zone. The SSN also has the option of using Active Sonar and use its speed advantage within the continental shelf, the SSK can ill afford to do so.

On steel, from what I understand the special steel is to sustain the high diving depths SSN can afford but SSK's cannot.

Both the Los Angeles class and the Type 209 use HY 80 Steel. The operation depth of the submarine is a function of it's design.

The suitability of the SSK in littorals is a function of the small size of the submarine. That has the following implications on operations of the boat.

1) small displacement wave, as the sub moves under water. Which can be dismissed as a shallow water fishing trawler for any sea bed seismic sensor array. Delaying detection of the boat.

2) they don't require too much depth to keal space in order to conduct safe sub sea navigation. Thereby, they can operate close to the shore.

3) sub surface environment is an acoustic environment. The ability to discriminate against the target is function of the quality of Sonar arrays of the submarine. Active sonar is like a flash light. The moment it's used, every hydro phone will hear it and localise the submarine.

[Rakesh]

https://twitter.com/Varun55484761/statu ... 85665?s=20 ---> An illustration of Indian SSN from a tender document. May not be the actual design but atleast we can conclude that it will have Pumpjet Propulsion.

https://twitter.com/GODOFPARADOXES/stat ... 31202?s=20 ---> Possibly preliminary base configuration of DRDO SSN. It has pump-jet propulsor, with cross form rudders. Sail is positioned closer to bow, which IMO might indicate provisioning of space further aft for VLS, for launching cruise missiles including HCMs. Picture credit @Anshsin93355338

[RoyG]

Possible design of SSN?

https://twitter.com/ANI/status/1678799091466403840?s=20 ---> An MoU has been signed between Indian Navy, BARC and ECIL, Hyderabad yesterday in the presence of Western Naval Commander, Vice Admiral Dinesh Tripathi & Dept of Atomic Energy Secretary, Dr Ajit Kumar Mohanty to facilitate indigenous development and production of control systems for ships: Navy officials.

[Rakesh]

Possible design of SSN?

Great find. Thank You.

[RoyG]

Possible design of SSN?

Great find. Thank You.

Very similar to the general design you posted. Interesting that it has a swedish a26 chinned type sail and has the cross form rudder. Hard to visualize if it has pumpjet. Possible it could be a later edition with French assistance. Given the tubular design and experience with scorpene, maybe it will have single hull with anechoic tiling?

[nachiket]

https://twitter.com/GODOFPARADOXES/stat ... 31202?s=20 ---> Possibly preliminary base configuration of DRDO SSN. It has pump-jet propulsor, with cross form rudders. Sail is positioned closer to bow, which IMO might indicate provisioning of space further aft for VLS, for launching cruise missiles including HCMs. Picture credit @Anshsin93355338

God I hope the dreaded VLS requirement which delayed the P75I for years isn't making a comeback here. If this is supposed to be a hunter-killer sub let it be that instead of trying to make it a jack of all trades and compromise its performance by adding a VLS module. Wouldn't it be easier to design a Klub/Exocet type missile that can be launched from the torpedo tubes? Or just buy the Klub off the shelf. Yes it won't be as good as the Brahmos, but then not every vessel in the Navy needs to be armed with the Brahmos.

If we need sub-launched Brahmos (or potentially Nirbhay) capability, a minimally modified version of the Arihant can be built which only carries Brahmos missiles in its VLS - like a mini Oscar class.

[Pratyush]

Wouldn't it be easier to design a Klub/Exocet type missile that can be launched from the torpedo tubes?

The DRDO is working on such a weapon already for the Submarine arm.

[Manish_P]

^ Noob question. Knowing the cramped storage space in the submarines, how easy (difficult) is it to have a) storage and b) loading the mixed load of SLCMs and Torpedoes firing from the torpedo tubes.

Does it require a lot of prep work or has it come to that level (automated) like say a tank gun getting loaded with APFSDS & HEAT rounds?

Are there dedicated tubes for firing the missiles and those for firing the torpedoes?

[souravB]

I just hope NDB goes the whole hog & design the SSN with electric propulsion in mind. Even if they go with 35MW PMM type motor, for which there was a TDF grant a while ago to build a scalable prototype, it'll be a huge step up in stealth. France et.al. are moving towards Rim Driven Propellers, fancy way of saying integrated propellers into the motor ergo no shaft at all, which is another step forward.

[Kersi]

Correct me if i am wrong
There are 2 ways of propulsion of a nuclear submarine
OPTION 1
The nuclear reactor generates steam. The steam turbine drives an alternator which generates electric power. This electric power charges the batteries. The batteries supply power to an electric motor which drive the propellor, through a gear box
OPTION 2
The nuclear reactor generates steam. The steam turbine drives the propellor, through a gear box.

Which system is used in INS Arihant and her siblings ?

Which system is used in nuclear submarines of other countries ?

[Pratyush]

Arihant i don't know.

Other countries ships; geared turbines and shaft.

Experimental in service boats: turbo electric drive.

[souravB]

OPTION 1
The nuclear reactor generates steam. The steam turbine drives an alternator which generates electric power. This electric power charges the batteries. The batteries supply power to an electric motor which drive the propellor, through a gear box
OPTION 2
The nuclear reactor generates steam. The steam turbine drives the propellor, through a gear box.

OPTION 2 is the basic drive system.
With evolution of battery tech, Batteries are increasingly used to drive the non-propulsive functions onboard a submarine.
With some more evolution of battery tech, a hybrid propulsion system arose resembling an SSK where low speed propulsion can be handled by the battery powering a small electric motor connected to the propeller shaft but full speed can only be achieved with steam turbine driven shaft.

The issue to moving towards full electric propulsion was till date a power dense electric motor to fit into a submarine. Columbia class is said to be coming with such a motor.

[Rakesh]

^ Noob question. Knowing the cramped storage space in the submarines, how easy (difficult) is it to have a) storage and b) loading the mixed load of SLCMs and Torpedoes firing from the torpedo tubes.

Does it require a lot of prep work or has it come to that level (automated) like say a tank gun getting loaded with APFSDS & HEAT rounds?

Are there dedicated tubes for firing the missiles and those for firing the torpedoes?

AFAIK, the tubes are the same. Missiles are stored right alongside torpedoes in the torpedo room. I believe there is some kind of rail system to load either torpedoes or missiles into the torpedo tubes, depending on the need.

While the submarine is cramped all over, the torpedo room (in my personal opinion) is the most roomiest aboard the Kilo Class. That is the perception I got, when I stepped inside a Sindhughosh (Kilo) Class boat.

The prep should be similar, as the SOPs to load a missile or torpedo should be more or less same.

[Manish_P]

^ thanks. I thought the pre launch prep and launch procedures were different. I guess that's all in the past now.

[Rakesh]

Manish, check these videos out...

Sindhukirti Submarine Fires Torpedoes



Submarine USS Olympia Prepare to Launch Torpedo



Crawling Down A Torpedo Tube -US NAVY Nuclear Submarine



The Scary Process of Reloading Massive US Submarine Torpedoes



Torpedo Load to Torpedo Tube of US Navy Virginia-Class Nuclear Submarine

[Manish_P]

Thank you sir, i will.

[Kersi]

Can some body post a video clip of a torpedo being loaded into submarine ?

[Pratyush]

[Manish_P]

Manish, check these videos out...

..

I went through couple of videos. Will check in detail later.

Was searching for reading material (i am more at ease with the written word and pictures) on missiles launch mechanism/procedures from torpedo tubes (not torpedo launches per se)

Found this - SW820-AP-MMI-010 Capsule for the Tomahawk SLCM
- https://navytribe.files.wordpress.com/2 ... mi-010.pdf

Specifically from page 42 onwards (images on page 87 ?)

There are very few articles about the Submarine Horizontal Launch TACTOM Capsule (SHLTC) which is apparently used to launch the tomahawks from the torpedo tubes. A barebones one - https://patentimages.storage.googleapis ... 427574.pdf

Has helped my understanding a bit more. If i have understood right, the advantages outweigh the disadvantages.

Thanks again.

[Kersi]

THANKS

[wig]

India engages in talks with France to develop six nuclear-powered submarines
https://www.msn.com/en-in/news/India/in ... 077a&ei=16

extracts

With the lease of the Russian Akula class nuclear-powered submarine concluding in 2021, the Indian Navy presently lacks any SSNs in its fleet. To address this critical gap, India has initiated discussions with France, exploring the possibility of a collaborative project to construct the required six SSNs.

and

In July, the Bhabha Atomic Research Center (BARC) and the Electronics Corporation of India Limited (ECIL) joined forces, signing an agreement to develop 11 types of control systems and multifunction consoles.

This collaboration aims to enhance the efficiency of SSN-related tasks and bolster India’s nuclear triad, which supports the established nuclear warfighting doctrine.

Currently, India possesses two nuclear-powered ballistic missile submarines (SSBNs), which primarily serve as instruments of the country’s nuclear deterrence and cannot be deployed for tactical missions.

However, the introduction of SSNs plays a vital role in countering numerically superior navies. These submarines possess the capability to stealthily track and follow targets, and their near invulnerability makes them a formidable weapon in the nation’s arsenal.

[Barath]

Correct me if i am wrong
There are 2 ways of propulsion of a nuclear submarine
Which system is used in INS Arihant and her siblings ?

Which system is used in nuclear submarines of other countries ?

Integrated electric power and propulsion or full electric propulsion is the name for option 2. Sometimes called electric drive

https://www.globalsecurity.org/military ... system.htm

"Two early nuclear-powered electric drive submarines: USS Tullibee (SSN-597, top), and USS Glenard P. Lipscomb (SSN-685, bottom). Immature electric-drive technology in the 1960s and 1970s limited the performance of these boats in comparison to their mechanical-drive counterparts."

Ie in general, mechanical propulsion was preferred.

https://www.businessinsider.com/columbi ... 018-6?IR=T

The upcoming Columbia class SSBN is supposed to have an electric drive.

I expect Arihant to have a mechanical drive.

Keep in mind that even nuclear submarines have electric batteries and in an emergency, with the reactor scrammed you may be able to use electric batteries for propulsion, not just equipment

There's also ideas of hybrid mechanical-electric system

https://www.rivieramm.com/news-content- ... ines-52644

[Barath]

Has helped my understanding a bit more. If i have understood right, the advantages outweigh the disadvantages.

Exocet from kalvari class, klub from kilos, harpoon from 2 of the sindhugosh class can be fired via the torpedo tubes. But many navies desire VLS for the greater capability/flexibility/growth options. Eg Korea, US virginia class blocks, yasen, oscar, india p75i proposed...

So not sure if you are comparing to vls when you say advantages of torpedo tube launch outweigh disadvantages. If the sub is designed not to have VLS, advantage is self explanatory.

Via HI Sutton the trade-offs are nuanced.

"Dr Rachel Pawling, who teaches naval architecture at University College London, suggests, “VLS is always going to hang around for those large air flight weapons where you want to launch several in quick order and don't care about reloads.” This would include larger hypersonic weapons such as Boost Glide missiles."

http://www.hisutton.com/Future-Submarine-2040.html

[Barath]

India engages in talks with France to develop six nuclear-powered submarines
https://www.msn.com/en-in/news/India/in ... 077a&ei=16

A second source.

https://www.firstpost.com/india/india-e ... 66862.html

Back in march it had been reported that France had offered India a deal to make 6 SSN, though there had been no public interest on the Indian side. : https://www.firstpost.com/world/after-a ... 02902.html

---

The history

> The Indian Navy has received in-principle approval for six SSNs and awaits the go-ahead from the Cabinet Committee on Security (CCS) to initiate the construction process.

Work on the SSNs started in 2015 and the CCS approval has been pending since at least 2021.

Seems like the primary reason why India would engage in talks with France is if the CCS felt that the proposal before them was too costly/risky/unfeasible. This may also be part of the reason why ccs approval is held up for 2.5 years

https://economictimes.indiatimes.com/ne ... s?from=mdr

> top Naval officer has said that work has started

At the time, it was targeting 15 years .. or 2030.

https://timesofindia.indiatimes.com/ind ... 770216.cms

"set" to get CCS approval nod March 2021.

Since indigenous SSN presumably leveraged Russian advice from the SSBN, involving france may result in change in concept/systems, potentially resulting in rework.

[Pratyush]

If the Indian Navy genuinely goes to France for development of nuclear submarine. We can rest assured that the Indian submarine will not enter service before 2050.

Unless India picks up off the shelf Barracuda. But then that is going to turn the Indian Navy into the next IAF.

This is bad news all arround.

[Manish_P]

...

So not sure if you are comparing to vls when you say advantages of torpedo tube launch outweigh disadvantages. If the sub is designed not to have VLS, advantage is self explanatory.

...

Yes, Barath ji. I meant for our current sub force which is overwhelming non VLS designed.

On a tangential note I had read an article a long time ago about some experimentation (don't recollect the country) about add-on VLS module concept

[Barath]

True, but except for 2 non upgraded shishumar class, every Indian sub in service* (ignoring SSBNs) has missiles it can fire through the torpedo tube. But the range is not great.

They can't help with dead/take out interdiction of Pakistani land assets (eg invasion) without a high and likely unacceptable risk to indian naval forces

And please, no ji

Re: add on vls module : The virginia class block v subs feature a VPM vls module instead of individual vls tubes of earlier blocks. Not sure, but it doesn't quite sound like the one you described. Which I assume was meant for MLU on existing subs ?

Also Saab has plans for a VLS module that can be adapted to any A26 sub. Too abstract right now to be definite but it sounds more like for future new bids than MLUs

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

Of existing indian submarines the kilo and shishumar are too old for the benefit to outweigh costs of design r&d or retrofit for a vls hull plug. The scorpenes are capable of accommodating a hull plug for AIP and thus one could discuss with the oem on vls module hull plug instead. But probably not likely

[Manish_P]

...
Re: add on vls module : The virginia class block v subs feature a VPM vls module instead of individual vls tubes of earlier blocks. Not sure, but it doesn't quite sound like the one you described. Which I assume was meant for MLU on existing subs ?
...

No, more like a out-of-the-box (literally ) variant of it.

The concept i read about/saw was somewhat like a 'attach-on' Missile carrier variant of the DDS (Dry Deck Shelter)... there are obvious disadvantages like constrictions on the diving depth, maneuverability etc



USSOCOM’s mini-subs progress into the 2020s

One interesting tidbit in the article

At the Leonardo virtual Expo Conference (virtual due to COVID-19) in July, 2020, a viewer in the audience postulated on if the Leonardo’s Black Scorpion™ miniature ultra-lightweight torpedo could be installed inside the SOCOM SDV MK 11 or the Dry Combat Submersible. The Leonardo virtual Expo presenter said that incorporating Black Scorpion torpedoes into the SDV MK 11 or DCS would require installing five-inch diameter torpedo tubes that can allow for six Black Scorpion torpedoes on the port and starboard sides, for a total inventory of twelve torpedoes per SDV MK 11 or DCS. Leonardo stated that this engineering challenge of arming a covert submersible with miniature torpedoes has not been tried, but the Black Scorpion has been installed on a 10-meter long boat.

The concept i had read had theorized about it as a missile-carrier instead of as a torpedo-carrier.

[Rakesh]

https://twitter.com/alpha_defense/statu ... 06688?s=20 ---> Unlimited Range of Democracy!

[sajaym]

https://twitter.com/alpha_defense/statu ... 06688?s=20 ---> Unlimited Range of Democracy!

Are the subs in this pic the S4 and the S4*, which are being referred to in this article? https://idrw.org/indias-to-begin-testin ... -gen-ssbn/

The sub in the foreground does appear to be slightly different from the one in the background even though both are the same size.

[Sagrawal]

https://twitter.com/vivekrathod17/statu ... 6497183852

Arihant video footage.

[Pratyush]

The pictures linked of Indian nuclear boats are pre Arihant concept studies.

If Arihant for all her hump has a near smooth structure.

Her followup is not going to have such a pronounced hump.

[Rakesh]

Hope floats for augmentation of Navy’s underwater assets
https://www.tribuneindia.com/news/comme ... ets-547720
26 Sept 2023

As per the Horizon 2047 document, India and France agreed to ‘explore more ambitious projects to develop the Indian submarine fleet and its performance’.

[Rakesh]

https://x.com/Chopsyturvey/status/17635 ... 32042?s=20 ---> What India needs most urgently are to more SSBN and six SSN, among many other things.

https://x.com/SandeepUnnithan/status/17 ... 01964?s=20 ---> Our SSBNs are coming…but without the SSNs to escort them! Only major world navy without SSNs and the long lead times to build them indigenously - as opposed to single unit leases- inspires dread. And we haven’t even started.

https://x.com/dravirmani/status/1763788 ... 84502?s=20 ---> The case for escort submarines in faraway waters is clear, but I have not seen an analysis showing the complementary role of Land based A2AD systems (including P8i s) in protecting Indian SSBNs located in the Indian Ocean? Reference?

https://x.com/SandeepUnnithan/status/17 ... 49095?s=20 ---> Faraway waters / deterrence patrols, SSBNs are on their own- ‘hide with pride’. SSNs needed to escort SSBNs in and out of harbour - when they are surfaced, and vulnerable…for aggressive sanitisation sweeps to interdict enemy HKs outside SSBN bases. Usually done in concert with surface assets - ASW aircraft, surface ships (a la Russian bastion exit drills) until the boomers can disappear into the depths.

https://x.com/SandeepUnnithan/status/17 ... 37435?s=20 ---> ‘The CNS (Ronnie Pereira) surprisingly rejected the (Russian N subs) offer in a strongly worded note… He felt it would neither strengthen the Navy’s submarine arm nor add muscle to India’s maritime forces’. War in the Indian Ocean. Vice Admiral MK Roy. Overruled by Mrs Gandhi. (Astonishing how our politicians seem wiser than our chiefs).

[pushkar.bhat]

For some reason, I get a strong feeling that L&T needs to master the pump jet and 3000 Long Tonnes submarine class and so we may end up buying the S-80.

Our SSN may end up being a derivative of the S-80, which has much commonality with the Scorpene.

[srai]

Indian SSBN in the deep waters of Bay of Bengal cuddled between IN’s A&N and Eastern command assets will be well protected even without SSNs.

[Lisa]

https://x.com/SandeepUnnithan/status/17 ... 01964?s=20 ---> Our SSBNs are coming…but without the SSNs to escort them! Only major world navy without SSNs and the long lead times to build them indigenously - as opposed to single unit leases- inspires dread. And we haven’t even started.

I do not think that this is strictly true. I have discussed this at length with a friend who does this for a living and was told in no uncertain terms that such escorts were a fallacy. I am happy to be corrected.

[ShauryaT]

Indian SSBN in the deep waters of Bay of Bengal cuddled between IN’s A&N and Eastern command assets will be well protected even without SSNs.

It would mean IN is already defensive against PLAN and cannot deploy any meaningful assets in the SCS to deter PLAN from entering Indian backwaters. I know we have talked about the SSN for decades now with no meaningful progress but only a plan B option would not strengthen our deterrence, conventional and strategic. SSN's are vital not only to protect SSBN's but also to deter PLAN from entering our lakes.

A controversial idea would be to "lease" the Virginia class AKA AUKUS style deal as a stopgap? It will put the "strategic" relationship to its true test.

[srai]

^^^
To sustain deterrence in SCS, India needs naval basing/support strategic agreements with friendly nations in the region like Vietnam, Philippines, Malaysia, Indonesia and Singapore.