Indian Navy News & Discussion - 03 July 2018

kit · Post by **kit** » 29 Jun 2019 15:25

Vivek K wrote:Agree with that! Why is there little stomach for risk taking? Indians want success guaranteed and therefore get left behind.

I think its more of the capability vs Threat perception

India is a democracy, we care about the number of body bags returning home rather than the autocracy next door. If we have a choice, we need both capability and numbers. I dare say we are doing both within our constraints, granted efficiency needs to improve

mody · Post by **mody** » 29 Jun 2019 15:48

Why we aren't leveraging the design blueprints of the U209 and design of scorpene to come with a new hybrid SSK is distressing. It is just being risk averse and not wanting to design something on our own.
Trying to get a proven foreign design to be built in India and then after building 6 thinking that we will come with our own solution, is not going to get us anywhere. The same was supposed to be the case, when we signed up for the scorpene. Now we have almost finished building 6 scorpenes, and it doesn't seem we have gained enough knowledge to build a sub on our own.

We have sufficient knowhow to build the hull, we have our own sonars, that we are using with the Kilo class, we have battery technology, though we can do with better tech. Maybe we can partner with the Japanese to get better battery technology. Any other modules of parts, like a good quite diesel engine etc. that we don't have expertise in, try to import from the French or Germans, but the overall design should be ours. We can probably even have our own motors, that we run the sub, when running on electric power. Now we even have our own torpedoes for the subs. When the Brahmos NG/Brahmos M come online, we will have our own anti-ship missile as well. I don't think the current Brahmos is suitable for fitment inside a 2,000 ton diesel sub.

chola · Post by **chola** » 29 Jun 2019 17:08

nam wrote:Three reasons:

1. SSK are cheaper than SSN, allows us to augment numbers. Khan can afford all SSN, bcoz.. it is Khan.
2. SSK are quieter than SSN, with fuel cells tech it is even more difficult to track.
3. SSK are smaller than SSN, allows for litoral warfare. SSN have trouble going very near shoreline.. remember the brand new british SSN getting stuck..

We can argue about foreign vs desi..

If they were cheap then I would agree but not in our case with phoren deal. A half billion USD for a 2K ton warship like Scorpene?

And why would we be fighting on our littoral? The one danger in our green water would be PN subs but those are not countered by SSKs but by ASW aircraft and surface vessels. We do not need SSKs creeping up on PN surface ships. Those will be annihilated in straight forward fashion by our destroyers and aircraft.

SSKs are used by weak militaries expecting phoren warships in their own littorals. We will not see any phoren warships in our littorals. Not in the face of the IAF as well as the IN.

We are better off with an all nook force that can operate in blue water. IMHO. We can get a few SSK once we can build them ourselves. Far better to use that budget on our SSN program than to feed some phoren MIC for some marginally useful conventional sub.

Arun.prabhu · Post by **Arun.prabhu** » 29 Jun 2019 20:34

SSKs are quieter. SSNs have more range and longer endurance. American policy has been to dominate the world's oceans, which requires a fleet of subs that can go on patrols around the world to project force, interdict shipping, etc. Their defense strategy is to ensure that their navy is stronger than all the other navies of the world combined, which is the case for now and for the foreseeable future.

American isolationist policy may force our planners to switch to a predominantly nuclear powered fleet in the decades to come to protect our supply and trade lanes in the high seas, but for right now, when we are concerned mostly with defending our backyard from Pakistan, taking out China's string of pearls and slitting their throat by interdicting their raw material and energy supplies, what we have is a good mix. And so long as we can defend Andaman and Nicobar and quite possibly lakshwadeep, what we have is more than enough. China may outnumber us in terms of hulls and they may have more tonnage in service, but that doesn't mean squat because they can't deploy all of it to combat us in our backyard. They don't have the logistics wherewithal if we take out their string of pearls, they'll be acting far from home and they have a hell of a lot of area to protect and keep an eye on in the high seas because they have pissed off damn everyone.

And worry not about the PLAN SSN advantage. Remember, they have hidden their sub base inside a mountain with tunneled exit(s). One exit is operational, but others may or may not be (corruption being what it is in China. Collapse those tunnels and bye-bye China's submarine force projection endurance.

chola wrote:
nam wrote:Three reasons:

1. SSK are cheaper than SSN, allows us to augment numbers. Khan can afford all SSN, bcoz.. it is Khan.
2. SSK are quieter than SSN, with fuel cells tech it is even more difficult to track.
3. SSK are smaller than SSN, allows for litoral warfare. SSN have trouble going very near shoreline.. remember the brand new british SSN getting stuck..

We can argue about foreign vs desi..
If they were cheap then I would agree but not in our case with phoren deal. A half billion USD for a 2K ton warship like Scorpene?

And why would we be fighting on our littoral? The one danger in our green water would be PN subs but those are not countered by SSKs but by ASW aircraft and surface vessels. We do not need SSKs creeping up on PN surface ships. Those will be annihilated in straight forward fashion by our destroyers and aircraft.

SSKs are used by weak militaries expecting phoren warships in their own littorals. We will not see any phoren warships in our littorals. Not in the face of the IAF as well as the IN.

We are better off with an all nook force that can operate in blue water. IMHO. We can get a few SSK once we can build them ourselves. Far better to use that budget on our SSN program than to feed some phoren MIC for some marginally useful conventional sub.

Philip · Post by **Philip** » 30 Jun 2019 08:53

Advanced Kilos were available for just $300M+ at the rate of one every two years.Perhaps $400M the price of supposedly more advanced Amurs .This is still at least $150M cheaper than either a Scorpene of U-boat. The main decision that confronts the IN is the type of AIP system aboard.Sadly not a single Scorpene comes with AIP when almost all subs being acquired by other tier-2/3 nations have AIP. The DRDO AIP system has yet to surface or be tested aboard a sub.The Ru diesel reformation AIP system too hasn't yet been seen aboard any of its subs as yet but will probably arrive soon aboard the Amur/ Ladas now entering series production.
Ne Li battery banks which could obviate or even improve an AIP system are in the works in Japan and probably SoKo too.

However, the IN should not fall into the trap of trying to build a conventional sub which has N-boat features.We are building a series of SSNs and should thus concentrate upon building a fleet of AIP subs that are both capable for our IOR needs and also cost-effective. The cost of the new subs should not cost more than $500 to 600+ M per boat.We would be able to acquire 6 plus infra/ trg. and weaponry in a package for around $7.5 to 8 B.Vietnam got her 6 Kilos for just under $2B.Weaponry like UW BMos have already been developed at home .So have sonars, some decoys, heavyweight torpedoes and other eqpt. which could be fitted onto the sub design chosen reducing costs.

nam · Post by **nam** » 02 Jul 2019 17:06

chola wrote: If they were cheap then I would agree but not in our case with phoren deal. A half billion USD for a 2K ton warship like Scorpene?

A SSN is in the range of 2-3 billion per unit! You get 4-6 SSK for that money!

Khan has no fear of a SSK sneaking in to it's water. All it's subs are for "far east world wars".

We have Pak SSK right next door. So need littoral capability, to prevent them for example, from blocking our ports.

For hunting "visiting Chini" SSN, we need our SSN.

John · Post by **John** » 02 Jul 2019 19:10

A SSN is in the range of 2-3 billion per unit! You get 4-6 SSK for that money!

Which SSK? Kilos perhaps but high maintenance costs and technology wise they are multiple generations behind the Scorpene (even agosta has a better combat management system than the Kilo).

Unless you build fully indigenous SSK based on 209s you are not going to get those numbers. Scorpene cost well over 1 bill each (adj for inflation) and P-75i are allocated similar cost but likely to be double that if history holds true.

Vips · Post by **Vips** » 02 Jul 2019 19:30

If cost is the criteria then South Korea is churning out advanced versions of U209 Submarines for $350 Million and change. India should prefer these any day over the Kilos.

Gagan · Post by **Gagan** » 03 Jul 2019 05:21

Hai Philip ji
Will you not stop trying to peddle Roosi goods to BRFites?

Every 3rd or 4th post of yours is like a salesman pitch - "Falana Roosi product is available for falana dollahs"
If you want to do the sales pitch, please also mention life cycle costs, and maintenence issues vis-a-vis a comparable western product

Thank Yoo

Vivek K · Post by **Vivek K** » 03 Jul 2019 07:39

^^^^And how many price increases will be demanded before delivery and will spares ever be available or should we buy twice the hardware to scavenge and keep one running.

Ankit Desai · Post by **Ankit Desai** » 03 Jul 2019 08:31

Atlast some construction at cochin shipyard's free space. Hope to see large enough dry docks for destroyer or Aircraft carrier construction.

-Ankit

chola · Post by **chola** » 03 Jul 2019 15:52

nam wrote:
chola wrote: If they were cheap then I would agree but not in our case with phoren deal. A half billion USD for a 2K ton warship like Scorpene?

A SSN is in the range of 2-3 billion per unit! You get 4-6 SSK for that money!

Khan has no fear of a SSK sneaking in to it's water. All it's subs are for "far east world wars".

We have Pak SSK right next door. So need littoral capability, to prevent them for example, from blocking our ports.

For hunting "visiting Chini" SSN, we need our SSN.

No idea of what is the cost of our SSN program is but we know that the Scorpenes are north of $500M. To be perfectly honest, I rather spend $2B locally on L&T for a SSN than $2B on DCN or any other gora firm for even four SSKs.

We will not be using slow, low endurance SSKs to hunt PN's SSKs. That's silly. We will be using ASW aircraft and surface ships with wide range and long persistence.

SSKs are mainly to ambush enemy surface ships in littoral waters. The Indian surface fleet and aircraft will not allow any phoren ship in our green waters to survive long enough for a slow moving conventional sub to reach it and attack it.

Again SSKs are for weak militaries expecting the enemy to operate in their home waters. We are not a weak military. SSNs are far more useful for us IMO.

Katare · Post by **Katare** » 03 Jul 2019 18:38

Philip wrote:Advanced Kilos were available for just $300M+ at the rate of one every two years.Perhaps $400M the price of supposedly more advanced Amurs .This is still at least $150M cheaper than either a Scorpene of U-boat. The main decision that confronts the IN is the type of AIP system aboard.Sadly not a single Scorpene comes with AIP when almost all subs being acquired by other tier-2/3 nations have AIP. The DRDO AIP system has yet to surface or be tested aboard a sub.The Ru diesel reformation AIP system too hasn't yet been seen aboard any of its subs as yet but will probably arrive soon aboard the Amur/ Ladas now entering series production.
Ne Li battery banks which could obviate or even improve an AIP system are in the works in Japan and probably SoKo too.

However, the IN should not fall into the trap of trying to build a conventional sub which has N-boat features.We are building a series of SSNs and should thus concentrate upon building a fleet of AIP subs that are both capable for our IOR needs and also cost-effective. The cost of the new subs should not cost more than $500 to 600+ M per boat.We would be able to acquire 6 plus infra/ trg. and weaponry in a package for around $7.5 to 8 B.Vietnam got her 6 Kilos for just under $2B.Weaponry like UW BMos have already been developed at home .So have sonars, some decoys, heavyweight torpedoes and other eqpt. which could be fitted onto the sub design chosen reducing costs.

They will cost 3x in maintenance and only be operational half the time. So in reality you get the bragging rights to say we have xx numbers but that doesn’t get you the capability to fight wars . IN is smarter than you think

Rakesh · Post by **Rakesh** » 03 Jul 2019 23:17

https://twitter.com/livefist/status/1145303773771776000 ---> The Indian Navy's Kilo Class submarine INS Sindhukirti had on board Defence Minister Rajnath Singh today at Visakhapatnam.

Prithwiraj · Post by **Prithwiraj** » 03 Jul 2019 23:49

whats the point?....

Karan M · Post by **Karan M** » 04 Jul 2019 01:57

That's a L3 Communications periscope in a Russian hull.

Aditya_V · Post by **Aditya_V** » 04 Jul 2019 10:39

American equipment inside a Russian war machine.

Gagan · Post by **Gagan** » 04 Jul 2019 17:53

Installed during her 10 year long mid life upgrade at HSL 2006 to 2015.
She spent one third of her life on the drydock!
But she likely provided immense info towards the SSN program

Singha · Post by **Singha** » 04 Jul 2019 18:32

Arun.prabhu · Post by **Arun.prabhu** » 04 Jul 2019 19:02

Russian equipment with a quality rebuild and decent sensors makes for excellent war fighting equipment. Just ask the Israelis.

Aditya_V wrote:American equipment inside a Russian war machine.

Philip · Post by **Philip** » 04 Jul 2019 20:06

There are no open source data on the maintenanence costs and operational time / yr. of any of the sub types in service.Such data would be highly classified.In general, western eqpt. is far more expensive than Ru. According to an old sea salt dolphin, who served on both U-boats and Ru subs, the Ru subs were more robust though they appeared dated inside.Extra system redundancy.Anyway, our U-boats are excellent boats too and I've always maintained building a new series to replace the 209s after the Scorpenes as those boats are too expensive and vital performance data compromosed.Moreover, OZ will get superior French subs whose latest eqpt. will not be given to India- a demand by the OZ govt. and promise which clinched the French the deal.

Another Ru line to replace Kilos is also long overdue as BMos can only be fitted onto Ru or desi N-boats. It will be v.interesting to see what type is offered for the P-75I contest.

Vips · Post by **Vips** » 04 Jul 2019 20:55

No way India should go for dry dock loving Soviet Subs, India should go for whichever German/Swedish/Spanish alternatives which comes with maximum and meaningful TOT. Should buy perpetual rights for unlimited numbers and not just for 6 to 12 units. (Something that South Korea did with the U209)

Philip · Post by **Philip** » 04 Jul 2019 22:35

Dry dock loving....? Don't forget not too long ago an IN Kilo got the better of a USN LA SSN in an exercise. We wouldn't be wanting another Akula too if they were useless.

Arun.prabhu · Post by **Arun.prabhu** » 04 Jul 2019 23:21

Philip, granted Kilos are very quiet, but don't tell me that aren't aware that USN - and for that matter, their Air Force, marines and army - regularly and intentionally lose during exercises so as not to hurt local sentiments. Now, I'm not saying that the IN is incompetent or that they let us win that particular game, but it's been known to happen whenever they have these games with middle eastern warriors, et al. In shallow littorals, diesels such as the Kilos will always have an advantage over nukes, the latter being large, inherently more noisy, etc. I know for a fact that we used a Kilo gimped with some of our home grown software and hardware brew to give it that extra oomph.

The Russians have some great war machine designs and their war fighting philosophy is one that I admire, but their QC is atrocious.

We leased the first Akula to get the systemology of running and fighting a nuclear sub. I suspect we're leasing the second for much the same reason so as to expand our nuke boat trained cadre much faster. It also gives us a very quiet opponent for training exercises to train our diesel crews to fight a nuclear boat. That is necessary as sooner or latter, the Chinese are going to manage a good nuclear attack boat.

Philip wrote:Dry dock loving....? Don't forget not too long ago an IN Kilo got the better of a USN LA SSN in an exercise. We wouldn't be wanting another Akula too if they were useless.

Vips · Post by **Vips** » 05 Jul 2019 05:25

It is common sense that a Diesel electric submarine is much quieter then a nuclear one. If a Kilo surprised the USN submarine "in an exercise" then most certianly a U class can too. It is not the machine but the tactics.

Aditya_V · Post by **Aditya_V** » 05 Jul 2019 16:20

Yes, but Diesel Electric subs are far slower and if they go faster it will eat into endurance. Many AIP systems are noisy when run at speed and in order to extend range the subs using AIP move at 3 or 4 knots. So basically they lie in ambush to launch thier missiles or torpedos. They are unsuitable for CBG protection etc as they cannot easily keep up with the rest of the fleet.

But in the shallow shelf of the Arabian sea, for the IN it is a must have for certain tasks.

Arun.prabhu · Post by **Arun.prabhu** » 05 Jul 2019 16:37

How fast do you think SSNs prowl when they are hunting? Subs are ambush predators of the deeps.

Aditya_V wrote:Yes, but Diesel Electric subs are far slower and if go faster it will eat into endurance. Many AIP systems are noisy when run at speed and in order to extend range the subs using AIP move at 1 or 2 knots. So basically they lie in ambush to launch thier missiles or torpedos. They are unsuitable for CBG protection etc as they cannot easily keep up with the rest of the fleet.

But in the shallow shelf of the Arabian sea, for the IN it is a must have for certain tasks.

Aditya_V · Post by **Aditya_V** » 05 Jul 2019 16:42

Sure they are slow, but I think SSK or AIP subs are much slower and far less weaponry.

John · Post by **John** » 05 Jul 2019 16:58

Arun.prabhu wrote:How fast do you think SSNs prowl when they are hunting? Subs are ambush predators of the deeps.

Aditya_V wrote:Yes, but Diesel Electric subs are far slower and if go faster it will eat into endurance. Many AIP systems are noisy when run at speed and in order to extend range the subs using AIP move at 1 or 2 knots. So basically they lie in ambush to launch thier missiles or torpedos. They are unsuitable for CBG protection etc as they cannot easily keep up with the rest of the fleet.

But in the shallow shelf of the Arabian sea, for the IN it is a must have for certain tasks.

Problem with SSK they need to deployed in large numbers to be effective or placed in choke points otherwise their effectiveness will be rather limited. Keep in mind there cruising speed is much lower than top speed where as nuclear vessels can operate close to top speed without range limitations.

SSN in other hand can be deployed in Asuw roles or Ashw quite effectively since they can catch up quite easily with most enemy fleets or quickly be steered to hunt down enemy sub operating few hundred nm away (good luck covering that distance with a SSK).That said the game changer I believe is unmanned battery powered submersibles which can be much cheaper and travel much faster than SSK but we are a decade or so away from seeing them in large nos.

Singha · Post by **Singha** » 05 Jul 2019 16:59

the latest soryu hull is the first one to shift into Li-ion batteries.

Arun.prabhu · Post by **Arun.prabhu** » 05 Jul 2019 19:59

No nuke boat captain is ever going to drive at top speed or anywhere close to it. Speed is noisy. It causes cavitation, the engines are noisy under load, it causes excess heat, which have to be shed - which is another signature that anyone with satellite will pick up, it messes up the effectiveness of your passive sensors...

The Seawolf class is claimed to be able to cruise at 20kts and still be stealthy - but only at depths because near the surface, 20kts will cause cavitation - but most submarines cruise at something like 5kts. The day in a typical submarine on the prowl for targets would be something like this: move very slowly for a few knots. Find the quietest spot. Listen very hard for the prey... Move very slowly to the next position. Find the quietest spot. Listen very hard for the prey... You get the idea...

You keep talking about how SSNs have unlimited range, but they are limited by the food they carry, the weapons they expend... And once a sub fires, it doesn't matter if it's a diesel boat or a nuke, it's position is made, the stealth is gone for a wee as it's position is localized and the ASW on the surface will have a jolly good time hunting it with MAD, dipped sonar, etc.

John wrote:
Arun.prabhu wrote:How fast do you think SSNs prowl when they are hunting? Subs are ambush predators of the deeps.

Problem with SSK they need to deployed in large numbers to be effective or placed in choke points otherwise their effectiveness will be rather limited. Keep in mind there cruising speed is much lower than top speed where as nuclear vessels can operate close to top speed without range limitations.

SSN in other hand can be deployed in Asuw roles or Ashw quite effectively since they can catch up quite easily with most enemy fleets or quickly be steered to hunt down enemy sub operating few hundred nm away (good luck covering that distance with a SSK).That said the game changer I believe is unmanned battery powered submersibles which can be much cheaper and travel much faster than SSK but we are a decade or so away from seeing them in large nos.

sudeepj · Post by **sudeepj** » 05 Jul 2019 23:48

Singha wrote:the latest soryu hull is the first one to shift into Li-ion batteries.

Li-Ions will almost make AIP obsolete. A lot less noisy, less volume/complexity than AIP, instant power ramp, stable chemistries are available.. Whats not to like?

Arun.prabhu · Post by **Arun.prabhu** » 05 Jul 2019 23:55

The subs will have to surface to recharge the li batteries without AIP. Limited endurance, in other words. The li batteries would be smaller, which is just how the japs like their subs, but li batteries are not the holy grail.

sudeepj wrote:
Singha wrote:the latest soryu hull is the first one to shift into Li-ion batteries.
Li-Ions will almost make AIP obsolete. A lot less noisy, less volume/complexity than AIP, instant power ramp, stable chemistries are available.. Whats not to like?

sudeepj · Post by **sudeepj** » 06 Jul 2019 01:00

Arun.prabhu wrote:The subs will have to surface to recharge the li batteries without AIP. Limited endurance, in other words. The li batteries would be smaller, which is just how the japs like their subs, but li batteries are not the holy grail.

sudeepj wrote:
Li-Ions will almost make AIP obsolete. A lot less noisy, less volume/complexity than AIP, instant power ramp, stable chemistries are available.. Whats not to like?

Even AIP will need to surface to recharge its batteries. The point is, if you move from Lead Acid to Lion, that increases your battery capacity by about 3 - 4 times. This is completely quiet, electric running time. Now, consider that the entire sub segment storing the AIP Section will also be storing Lion batteries, that will add another large chunk of quiet running time.

AIP is also much noisier.. E.g. MESMA burns ethanol and compressed oxygen (!!!!!) and exhausts the combustion products in the water. This process is bound to be noisy.. Being a turbine, it will also take its time spooling up to max power. It will also leave a chemtrail in the water which could be detected by chemical sensors. Compressed oxygen is a highly dangerous option. The Kockums option carries liquid oxygen and a sterling engine. Being underwater only means you evade radar, but you are still vulnerable to all kinds of other sensors.. Sonar, MAD, SonaBuoys etc.

Only fuel cell appears a bit promising, but here, power densities are comparable to Lion. So why introduce a new chemistry and a new fuel chain making it more complex? Even with fuel cells.. many chemistries are corrosive or highly flammable. To me, Lion appears to improve the diesel Subs endurance with none of the drawbacks of other AIP.

Pratyush · Post by **Pratyush** » 06 Jul 2019 09:03

Cavitation is an issue that was solved for most subs in the 70s and 80s.

Wake of the subs was the next problem.

The modern pumpjet propulsion system has reduced it to nothing.

The heat of the nuke reactor is a known issue. You have to have already localised a sub reasonably closely. Before using that heat as a detection sources.

So for a tier 1 Navy the advantages of a nuke propulsion out weight it's disadvantages.

arvin · Post by **arvin** » 06 Jul 2019 09:25

Agree with Li-ion assessment. One of the older kilos or the one rendered useless owing to torpedo loading explosion should be stripped of its lead acid batery and replaced with li-ion. Some kind of innovation would be required here just like tesla did it with battery of its electric cars. Endurance should be compared with PAFC AIP. I doubt such kind of experiments were done before going the PAFC route.

Philip · Post by **Philip** » 06 Jul 2019 12:00

U-boat sigs ard well known to NATO forces. Ru noats being usually doublehulled are quieter.Anechoic tiles and paints differ from cojntry to countty.The Alfa had the highest speed of over 40 kts, was noisy but was capable at depths much beyond NATO torpedo depths.Talso had small stealth screws for quiet running.The Lorashik secret ops sub which had a battery compartment fire killing 14 v.senior submariners, dives to 20, 000ft.Few current subs dive upto 600m (2,000 ft) .An N boat can operate for a 3 month endurance period unlike a vonv. boat, usually 45 days at a lesser range , upto 60 with AIP. , better suited forl ops In the littorals, Therefore the IN is faced with a somewhat similar situ as the Russians, who use conv. boats for littoral warfare and N -boats for true blue open ocean ops.
The skill is finding the right mix.

Arun.prabhu · Post by **Arun.prabhu** » 06 Jul 2019 21:19

Chemtrails in water are like scents on land. Wind and everything else have to work fine for you to trace it. One way to fool chem sensors would be to sink packages that'll leak the chems in small quantities for a long time. If everything smells of sub, nothing is a sub.

The increased capacity comes with a commensurate increase in charging time. You'll have to spend that much longer on the surface or run the diesels at higher rpm - thus making more noise - to generate more power to charge faster. Li-ion allows boats to spend longer under water, playing their stalking game, which is where the sole advantage lies. Higher power densities come with higher risk of fire accidents.

sonobuoys are sonar on buoys.

sudeepj wrote:
Even AIP will need to surface to recharge its batteries. The point is, if you move from Lead Acid to Lion, that increases your battery capacity by about 3 - 4 times. This is completely quiet, electric running time. Now, consider that the entire sub segment storing the AIP Section will also be storing Lion batteries, that will add another large chunk of quiet running time.

AIP is also much noisier.. E.g. MESMA burns ethanol and compressed oxygen (!!!!!) and exhausts the combustion products in the water. This process is bound to be noisy.. Being a turbine, it will also take its time spooling up to max power. It will also leave a chemtrail in the water which could be detected by chemical sensors. Compressed oxygen is a highly dangerous option. The Kockums option carries liquid oxygen and a sterling engine. Being underwater only means you evade radar, but you are still vulnerable to all kinds of other sensors.. Sonar, MAD, SonaBuoys etc.

Only fuel cell appears a bit promising, but here, power densities are comparable to Lion. So why introduce a new chemistry and a new fuel chain making it more complex? Even with fuel cells.. many chemistries are corrosive or highly flammable. To me, Lion appears to improve the diesel Subs endurance with none of the drawbacks of other AIP.

Arun.prabhu · Post by **Arun.prabhu** » 06 Jul 2019 21:33

Cavitation in the deeps was solved. The closer you are to the surface, the slower you go or there will be cavitation. Good engineering will reduce it, but physics dictates it.

Pratyush wrote:Cavitation is an issue that was solved for most subs in the 70s and 80s.

Wake of the subs was the next problem.

The modern pumpjet propulsion system has reduced it to nothing.

The heat of the nuke reactor is a known issue. You have to have already localised a sub reasonably closely. Before using that heat as a detection sources.

So for a tier 1 Navy the advantages of a nuke propulsion out weight it's disadvantages.

chola · Post by **chola** » 07 Jul 2019 13:22

https://m.economictimes.com/news/defenc ... 034247.cms

India seeks to buy $2.2 billion warships to meet China challenge

The Modi govt on Monday asked seven shipyards to submit proposals for the construction of six missile warships and other smaller vessels worth 150 billion rupees, the Ministry of Defence said.

By Bloomberg | Jul 02, 2019, 08.25 AM IST

By N. C. Bipindra
India sought bids for purchase of warships and support vessels for its navy and coast guard as it ramps up security of its maritime border in the Indian Ocean region.

The Narendra Modi government on Monday asked seven shipyards to submit proposals for the construction of six missile warships and other smaller vessels worth 150 billion rupees ($2.2 billion), the Ministry of Defence said in a statement. The tender includes eight fast patrol vessels, 12 hovercrafts and eight missile-cum-ammunition barges.

The shipbuilders invited include private shipyards Larsen & Toubro Ltd. and Reliance Naval & Engineering Ltd., apart from the state-run Mazagon Dock Shipbuilders Ltd., Garden Reach Shipbuilders and Engineers Ltd., Goa Shipyard Ltd., Hindustan Shipyard Ltd. and Cochin Shipyard Ltd., people with knowledge of the matter said. They asked not to be identified citing rules.

Anyone with an idea as to what a "missile-cum-ammunition barge" is? Sounds interesting.

No mention of phoren firms so all indigenous effort? On the FACs, more Vikrams for CG? Or something new? Maybe for regular navy?

Hovercraft I assume would be the Griffon produced at GRSE?

(Dumb DDM headline. Cheen's handful of ships in the IOR steer a wide berth from our territorial waters. They mount no challenge where these proposed vessels can operate.)