Project 75 India Diesel-electric Submarine Programs (SSK) : Updates and Discussions

Austerlitz

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All the subs can actually carry 12 Brahmos. Even the 950T version of Amur has been advertised with 8 Brahmos VLS.



That isn't the cost of the sub alone, it includes the cost of R&D, production facilities, training, and also maintenance for decades. The actual sub itself is likely less than half.



It's doable with local steel, AIP, weapons, CMS etc. I won't be surprised if IN asks for all or most of the electronics to be Indian anyway.

What is stopping us from designing indigenous submarine ssk i never understood.We build aircraft carriers and ssbns,but no diesel subs wtf.
 

randomradio

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What is stopping us from designing indigenous submarine ssk i never understood.We build aircraft carriers and ssbns,but no diesel subs wtf.

There is a plan to do that later on. Right now, the IN wants the comfort of proven capability and proper after sales support. Also, we are yet to make diesel engines of this class, which is extremely difficult. Others won't simply sell you this tech after all.
 

Sathya

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There is a plan to do that later on. Right now, the IN wants the comfort of proven capability and proper after sales support. Also, we are yet to make diesel engines of this class, which is extremely difficult. Others won't simply sell you this tech after all.

Even after building 6 scorpenes ?

------

Btw which submarine will fulfill the Navy criteria ?
 

randomradio

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Even after building 6 scorpenes ?

We don't own the IPR for it or yet have the expertise necessary to make a submarine capable engine. Even the Chinese are just license building German diesel engines for their frigates and destroyers. Their AIP is basically a license built Kokums Stirling engine imported from Sweden. The Type 039A also uses German diesel engines.

They got quite a bit of tech in the 80s because of the need to counterbalance the Soviets. We won't be that lucky.

Btw which submarine will fulfill the Navy criteria ?

Don't even know what's their criteria yet.

SMX Ocean will simply surpass all specs, but if another sub is shortlisted, then it will lose due to costs. So France may participate with a bigger Scorpene or the SMX Ocean, depending on the RFP. So I'm not going to hold my breath for the SMX Ocean. For now, I would put the A26 on top of the list. It's after all the latest in SSK design and the fact that the Swedes have opted to build 2 for themselves. Apart from SMX Ocean and A26, no other subs in a bigger version have orders placed.

Saab Expands its A26 Submarine Offer with now Three Variants to Choose From

Best not to go for Russian subs. Type 214 and Scorpene are very old designs. So my money's on the SMX Ocean or the A26.
 
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Sathya

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Project Pandoobi I believe.

Pandoobi in hindi mean s Submarine ?

I learnt a new hindi word ..

Why have you commented that way ?

I felt conditions layed down according to the news paper is hard to fulfill, is there any sub company that s listed possible to fulfill ?

Especially giving up their IPR rights
 
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Ankit Kumar

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Its mere speculation as of now. The upcoming FY and even the next one will see most of the CAPEX going towards payments for LR-SAM, MH60R, additional P8I, payments for 17 Dhruvs, additional funds for last stage completion of IAC-1 , then funds for Heavyweight Torpedo acquisition and the N-LUH whoes RFP is expected soon.

Simple logic says we obtain F21 torpedos from France, submarine launched SCALP from France and add them to our Scorpene fleet and place a follow on order of 6 more units for now.
 
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sid4587

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The best option is the SMX Ocean. Greater cruise speed, greater endurance, greater range and pumpjet propulsion. It should easily be able to manage greater depths also.

Cruise speed is 14kn, while other subs can only manage up to 8kn. Endurance is 90 days for a crew of 60, while most other subs can manage 45-50 days with a crew of 30-35. And range is 18000nm versus 6000 to 12000nm on other subs. This makes the SMX Ocean a proper ocean going sub. What it means is the sub can go underwater to Malacca Strait in a week all the way from Vizag, stay underwater for a month, and then head back to Vizag underwater. So it can perform a full 45-day mission completely underwater from its home port at a range of 2000-2500Km. This is entirely impossible for all other subs, including Soryu.

Of course, all this comes at 2x the cost of other subs.

The next best option would either be the Type 216 or a larger Scorpene. But out of these two subs and the Soryu class, only the Soryu exists, while the other two are just paper boats. Any Russian option is also a paper boat, IN won't be interested in another Kilo class. Sweden does not have one either. So Soryu is practically the default option, while all the other designs are risky. But the Japanese have not replied to IN's RFI. So there's a good chance Soryu will not be an option. Only France, Germany, Russia and Sweden are competing.
This is entirely impossible using our AIP, its their AIP due to which they achieve such a great endurance. If we can have second generation fuel cell at the end of 10th year then may be yes.
 

randomradio

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This is entirely impossible using our AIP, its their AIP due to which they achieve such a great endurance. If we can have second generation fuel cell at the end of 10th year then may be yes.

Our AIP will be a much better option. Transit speeds rely on the diesel electric engine, not AIP. AIP is like an APU, it doesn't give you speed.
 
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RISING SUN

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Indian Navy looks Forward To DRDO’s Air Independent Propulsion System For Submarines
It seems a decision has been taken by the Indian Navy (IN) to install an air-independent propulsion (AIP) system developed by the Naval Materials Research Laboratory (NMRL), Ambernath, which is a part of the Defence Research & Development Organization (DRDO), on all six of its Scorpene class diesel-electric submarines once they become due for their first major refit. This decision is of course contingent upon NMRL’s AIP being fully proven by then as a ‘safe plug’. Given that the refit of even the first Scorpene Class submarine, the INS Kalvari, is not due for at least another six years, NMRL is confident of having refined its already advanced prototype sufficiently by that point, to satisfy IN’s requirements.

The earlier plan of installing NMRL’s AIP on the last two Scorpenes has been given up since NMRL’s AIP plug was not deemed sufficiently mature by the original equipment maker (OEM) of the Scorpene Class, France’s Naval Group, once known as DCNS. As such, it is felt by various stakeholders that it is now too late to install the AIP on the last two Scorpenes which are also at an advanced stage of construction.

However, IN has decided that even though the process of installing the AIP plug during refit will involve cutting open the hull of its Scorpene units, it would still be worth it, given that NMRL’s AIP boasts attractive features. In fact, NMRL believes that its Phosphoric Acid Fuel Cell (PAFC) based AIP solution is a step ahead of what the People’s Liberation Army Navy has obtained from Sweden in the form of a Stirling cycle based AIP for its submarines. Be that as it may, let us take a closer look at NMRL’s 250 kilowatt (kW) PAFC based AIP solution that allows up to 14 days of underwater endurance for a submarine running solely on power supplied by this system. Fig. 1 below gives the overall scheme behind NMRL’s AIP system.

NMRL’s AIP

NMRLAIP.png

Fig. 1: Overall scheme of NMRL’s AIP system. Source: NMRL


On-board hydrogen generation
While based on a proven fuel cell technology type i.e PAFC, NMRL’s AIP system, nonetheless, incorporates a set of innovations that make it a rather contemporary system. For one, NMRL’s AIP package has an onboard hydrogen generation plant, which produces hydrogen ‘in situ’ unlike many other AIP configurations where hydrogen for a mission has to be carried on board. Moreover, on board hydrogen production in NMRL’s AIP does not require any kind of combustion. NMRL’s AIP supplies hydrogen ‘in situ’ by reacting hydrogen ‘rich’ sodium borohydride, which is carried on board, with water, to generate hydrogen and sodium metaborate (see Fig. 1, above). The advantages of this kind of ‘borohydride hydrolysis’ (BH) to generate hydrogen vis a vis other forms of on-board hydrogen generation are given below in Fig. 2. NMRL’s BH process generates a considerable amount of hydrogen without entailing the release of any gaseous effluents which add to system noise and can compromise submarine stealth. Moreover, BH plants also have long operational lives.

word-image-3.png

Fig. 2: A comparison of various on-board hydrogen plant processes. Source: NMRL


PAFC innovation

Now the hydrogen generated by BH is sent to the main power plant of the AIP system which is made up of PAFC stacks, which of course use phosphoric acid as an electrolyte. The electrodes of NMRL’s PAFC design are made of PTFE bonded platinum/ carbon. The electrode support is in the form of carbon paper and silicon carbide serves as the electrolyte support. A typical PAFC layout and process is depicted in Fig. 3 below.

NMRL-AIP-1.png

Fig. 3: Typical PAFC layout and operation. Source: NMRL


Basic PAFC technology is actually the oldest commercial grade FC technology in use today. However, the technology has seen constant improvements over the years and retains certain advantages over other FC types. PAFC has much longer service life than any other commercially viable FC type and has much better tolerance to impurities in the reactants used even when compared to polymer electrolyte membrane fuel cells (PEMFC). Naturally, PAFC does have its disadvantages too as compared to PEMFCs and more contemporary FC types. PAFC operating temperatures are usually higher in comparison to PEMFC and overall power to weight ratio is lower. A comparison of PAFC vis a vis other FC types is given in Fig 4 below.
word-image-4.png

Fig. 4: Comparison of PAFC with other FC types. Source: NMRL

Anyway, PAFC technology has evolved to become a rather useful option for ground based off-grid power supply. What NMRL has done is further develop basic PAFC -related know how to come up with indigenous PAFC stacks that are ruggedized and compact enough to be suitable for underwater marine applications with the relevant safety margins. A typical challenge with PAFCs is the need to handle its corrosive acid electrolyte while maintaining the concentration of the same. This requires the development of special corrosion resistant materials and detailed component engineering, both of which have been accomplished indigenously at NMRL. Indeed, NMRL has registered a number of innovation patents on its way to the development of indigenous PAFC stacks related to the catalysts used, sealants, acid holder matrix, carbon paper, etc. Much headway has also been made on acid management systems. The thrust of development has obviously been on lowering costs since the special materials used in a PAFC are not exactly cheap. For example, NMRL has developed low-cost graphite gas distributor plate materials for use in its PAFC stacks. NMRL has also experimented with special siloxane based microporous gels that enhance water retention to prevent the loss of design life that PAFC’s which have to undergo frequent stop/starts suffer from. NMRL’s PAFC also operates at a lower temperature than older generation PAFCs, apparently. This of course helps reduce the parasitic power load of the AIP system below that of a legacy PAFC based system, with the concurrent benefit of greater net output available for propulsive purposes.


Indigenous production

Importantly, NMRL’s development of indigenous PAFC stacks has been done in close cooperation with Indian industry. In fact, NMRL developed PAFCs are the first examples of successful industrialization of any FC type in India. NMRL has transferred PAFC technology to Thermax Ltd, Pune which began production with the supply of twenty-four 3 kW PAFC units for captive use at NMRL via a buy back arrangement. According to CSIR, Thermax’s facility ‘is provided with all sub-manufacturing modules to manufacture electrodes from basic raw materials, assemble them in the form of fuel cell stacks and conduct elaborate testing of each stack for meeting the strict quality control requirements of NMRL necessary for defence establishments’. It seems that large scale skilled manpower for the manufacture of fuel cells has also been developed in the course of industrializing NMRL’s PAFC technology.

NMRL and Thermax have now graduated to the production of the N11, 11.5 kW marine grade PAFC stack shown below that has a rugged cocoon structure and has passed shock and vibration tests that one may experience during intense underwater operations. Such parallel / series connected PAFC stacks can be used for power generation levels of up to 500 kW, thereby underlining the modularity of NMRL’s AIP solution which can be used in submarines other than the Scorpene as well.

word-image-2.png

Fig. 5: The N11, a 11.5 kW PAFC stack developed for NMRL’s AIP solution. Source: NMRL

Moreover, NMRL’s modular architecture scores over a composite system, since even if one of the modules fails, the control system for the PAFC stacks can reconfigure the remaining operational units to continue to supply power output, albeit at a reduced quantum. This naturally increases the survivability of the system, which is of utmost importance when being used to propel a submarine stealthily.


For the Scorpene and beyond
The current AIP prototype being tested at NMRL has been optimized for the form and fit of the Scorpene’s hull (see Fig. 6 below), although modules that fit other hull dimensions can be engineered as well.
NMRL-AIP-6.png

Fig. 6: NMRL’s AIP plug for the Scorpene Class submarines of the Indian Navy. Source: NMRL

This 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. Obviously, NMRL’s AIP has got no heavy rotating machinery and NMRL is confident that the module ‘maintains relative silence and retains its stealth characteristics’ throughout the platform’s envelope.

As such, the development of an indigenous AIP system by DRDO and its complete domestic industrialization is a significant milestone in the development of FC technology in India. Apart from the Scorpene programme, whatever diesel-electric submarine design is chosen for construction under Project-75I is also likely to be a recipient of NMRL’s AIP solution.
Indian Navy looks Forward To DRDO’s Air Independent Propulsion System For Submarines
 

sid4587

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Our AIP will be a much better option. Transit speeds rely on the diesel electric engine, not AIP. AIP is like an APU, it doesn't give you speed.
it gives us endurance, they use second generation fuel cell tech, no other SSK uses that version.
 

vstol Jockey

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it gives us endurance, they use second generation fuel cell tech, no other SSK uses that version.
Indian Navy has gone thru every AIP system available in the world. You can't become an officer in IN if you are not minimum a B.Tech with over 75% marks. IN has found DRDO AIP as the best solution. Please have faith in their knowledge and competence. DRDO maybe what they are, but at times even idiots come out with gem of knowledge. LOL.
 
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Ankit Kumar

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Indian Navy has gone thru every AIP system available in the world. You can't become an officer in IN if you are not minimum a B.Tech with over 75% marks. IN has found DRDO AIP as the best solution. Please have faith in their knowledge and competence. DRDO maybe what they are, but at times even idiots come out with gem of knowledge. LOL.
Only thing is that DRDO needs to certify it in time.
 

randomradio

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it gives us endurance, they use second generation fuel cell tech, no other SSK uses that version.

The term generation here is misleading. It's not defined like aircraft generations, which is like a relatively global standard. It is only an internal designation. For example, the Americans are making their 10th generation sub while the Russians are at 5th generation. It just means the number of sub classes built, nothing to do with technology itself.

The Indian AIP uses PAFC while the French use Lithium ion. So a direct comparison is impossible without hard data.
 
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A Person

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The term generation here is misleading. It's not defined like aircraft generations, which is like a relatively global standard.
Not really.

Aircraft generations didn't enter the mainstream until they were used as a marketing argument by Lockheed Martin to claim the F-35 was better than everything else. And before that, you had a completely different standard, proposed by Rich Hallion, in which the Mirage 2000 is sixth generation, the Jaguar is fifth, the MiG-21 is fourth, and so on.

Also China has its own system for its own aircraft, so the J-20 is fourth generation.
 

randomradio

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Not really.

Aircraft generations didn't enter the mainstream until they were used as a marketing argument by Lockheed Martin to claim the F-35 was better than everything else. And before that, you had a completely different standard, proposed by Rich Hallion, in which the Mirage 2000 is sixth generation, the Jaguar is fifth, the MiG-21 is fourth, and so on.

Also China has its own system for its own aircraft, so the J-20 is fourth generation.

That's fine. When you say generations for fighter jets, all aircraft of that generation will fall under one category based on capability. The same is not possible with most other stuff.

China's generations are similar to the American generation for submarines. It's specific only to them. In that sense, our first gen sub Arihant could be comparable to the 7th or 8th gen American sub. Similarly, the French 2nd gen AIP is specific to France only. So you can't put MESMA, Stirling, PAFC and Li-on on a list that separates them into generations.

Although we can do that based on capability, we have no idea what that is. So when one says the French use 2nd gen Li-on, the generation terminology used has no relevance since it doesn't reveal anything. It can even be 3rd gen or 4th gen and still be inferior to DRDO's current gen PAFC. Naturally, the reverse can also be true, where even a first gen Li-on can be superior to DRDO's PAFC. There is no metric to compare the two without actual data, unlike aircraft where we can be sure that one 4th gen aircraft can be quite competitive with another 4th gen aircraft since there are some established standards to how generation is defined in this specific area.