Project- 75(I). Next gen subs. RFP issued

Gessler

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Navy tilting towards Korean KSS? Proven AIP, Li-ion batteries, VLS tubes
VLS not a requirement - in fact the version of KSS that's being offered in P75I will not have any VLS according to the Koreans:


The AIP & LIB packages will have to be comparatively evaluated. Not impossible for the others to come up with LIB packages via some sort of sub-contract to another company, even from another country. What will ultimately matter is the reliability, power density & price of the package they offer.

Same goes for AIP. Doesn't matter if its already in use or not.
 

MonaLazy

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version of KSS that's being offered in P75I will not have any VLS
That's a June 2021 article from naval news. There is a more recent one from 3 days ago:


Specifically on the DSME-3000

DSME-3000, South Korea’s Missile Submarine
South Korea has recently spread its wings and entered the submarine export game, selling boats to Indonesia. They are understood to be proposing an export version of their home-grown KSS-III design. This is a relatively large non-nuclear boat, likely second only to the Barracuda.

The type comes with German based fuel-cell AIP. The layout, with a hull section essentially dedicated to AIP, suggests that it would not be too challenging to swap it for the Indian alternative.

And South Korea is ahead of most countries in the race to fit lithium-base battery technology to submarines. This promises to extend the endurance of submarines when running on batterie. Naturally this may be attractive to the Indian Navy, even potentially diminishing the importance of AIP.

Its differentiating feature is that it already comes with a six or ten round VLS. In South Korean service this is expected to carry the Hyunmoo 4-4 missile, which is roughly equivalent to India’s K-15 Sagarika but without a nuclear option. While exact dimensions and weights are not available, this at least implies that it could accommodate the similarly sized Brahmos.

Carrying a VLS in such a small submarine likely needs some trade-offs, like fewer weapons slots in the regular torpedo room. But overall the South Korean design seems balanced and highly capable.


Please see this post also:


1634463704623.png


1634463718255.jpeg


The above infographic does show a Brahmos ejecting from the VLS!
 
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Gessler

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That's a June 2021 article from naval news. There is a more recent one from 3 days ago:


Specifically on the DSME-3000





Please see this post also:


View attachment 114950

View attachment 114951

The above infographic does show a Brahmos ejecting from the VLS!
That is interpretation of HI Sutton.

The VLS requirement is not mentioned anywhere. Show me a single official document requiring it?

There's no indication that this was added in the RFP (which is only available for SP/OEMs btw, so HI Sutton couldn't have seen it even if it was) either.
 

Covfefe

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@MonaLazy @Gessler
Wouldn't the availability of VLS make it more attractive for the IN? Something like the twin engine option for IA's LUH. And do we have any of our own horizontally launched cruise missile?

Also for the AIP issue, wasn't the DRDO AIP rejected due to lack of a proof of concept on a working platform, leaving behind only two suppliers in the competition- German ThyssenKrup and Korean Daewoo? (The German company pulled out later due to ToT and localisation demands)
 

Gessler

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@MonaLazy @Gessler
Wouldn't the availability of VLS make it more attractive for the IN? Something like the twin engine option for IA's LUH. And do we have any of our own horizontally launched cruise missile?
The way Indian procurement system works - you meet the requirement, you get full marks. You don't meet the requirement, you get zero marks. Going above & beyond the requirement does not give you any extra marks.

Unless required, nobody will offer VLS because adding another module will increase cost, and make their offer less competitive in the cost negotiations, potentially losing out the contract.

Also for the AIP issue, wasn't the DRDO AIP rejected due to lack of a proof of concept on a working platform, leaving behind only two suppliers in the competition- German ThyssenKrup and Korean Daewoo? (The German company pulled out later due to ToT and localisation demands)
The DRDO AIP was never really meant for P-75I, but only for Scorpene refit. The intention was that the AIP could be ready by the time INS Kalvari comes in for its first major refit. I don't know for sure when that is scheduled.

I have heard something to the effect of having to be Operational-at-Sea, but we'll see what transpires. We aren't anywhere close to selecting an offer yet. That will only happen by around ~2025 or later.

Who knows how many changes could be introduced by then. Or even scrapping the whole thing and going back to square one. Wouldn't be the first time we did that in a deal of this scale.
 

MonaLazy

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A detailed look at Ozzie submarine experience starting with the Oberon class to Collins, the SEA-1000 cancellation & finally AUKUS.


Notables:
  1. Australia's first class of submarines the O boats were maintenance intensive - complete refit every 5 years- huge manhours, sustainment costs (manufactured and supported from UK)
  2. Essentially rebuild the submarine on every docking- crippling cost and availability by having to rely on foreign suppliers
  3. Why local manufacture for Collins class? Over and above the jobs from local manufacture of subs sustainment becomes easier- so direct imports are a strict no-no even with lower upfront costs
  4. Indiscretion rate- How often a DE (diesel-electric) submarine has to surface and recharge its batteries. DE subs spend a majority of their time running off electric propulsion- inherently quiet making the sub stealthy but batteries hold charge only for so long. As they are depleted the sub has to snorkel- putting its tube above the water & running diesel engines to recharge the batteries. Very visible & vulnerable time for the sub as the diesel engine is loud making it much less discreet and the sub has to remain at periscope depth. Over 4 hours for the Oberon class if the batteries were dead flat.
  5. Ideally, a sub must stay submerged longer and recharge its batteries faster
  6. Australian subs need to transit 6000 kms just to reach their patrol area in Andaman Sea, South China sea and Philippine sea- typically a job for larger subs with nuclear propulsion. So DE was an odd choice as they are small short-range vessels that are designed to be operated in a nations near seas.
  7. Endurance of the crew- less crew in more space is always better
  8. What made the Collins class unique was its size- 3500 tonnes. During its design period it was among the largest conventional subs ever made- substantially greater displacement than the Russian Kilo
    1. Increased internal volume which helped with endurance and indiscretion rate
    2. 50% greater displacement allowed a far larger number of batteries to be installed greatly improving the Collins submerged endurance- 3 or 4 days between snorkelling if the boat is being frugal
    3. The submerged performance of the Collins is over 4x greater than its predecessor the Oberon simply because of its volume and the size of its battery bank
    4. The boat's size allowed for much larger diesel generators- 4,2 MW electricity generation capacity allowing her to rapidly recharge batteries- again a 4x improvement over the Oberons
    5. Going at speed the Collins can recharge its batteries from depletion to full charge in 1 hour
    6. During initial sea trials HMAS Collins demonstrated that under typical patrol conditions when the boat was moving slowly & conserving energy she was able to run an energy cycle that required her to snorkel for just a couple of minutes every 24 hours
    7. In mid-1990s DSTO tested 2 AIP technologies one of which was the Sterling system used today by Kockums however the submerged performance of the Collins class was so good that these were immediately dropped- space, weight & cost penalty for oxidizer tanks etc did not offer a marked improvement over the baseline capability
    8. Capt Paul Greenfield of RAN remarked- "Sea trials of the first-of-class have proven that the Collins as it is now can stay submerged for such a long time, and have such a low rate of indiscretion, that a refit of an AIP system is not really needed and would simply have no cost-benefit."
    9. By building a boat as large as Collins and focussing the design around submerged endurance Oz had been able to produce a sub that had such a low indiscretion rate that AIP was not worth the installation
    10. By mid-2010s completely sustained by an Australian supply chain - for much higher availability and much lower sustainment costs than the Oberons. No more month-long delays waiting for international part suppliers during refits
    11. Capable of 90-day patrols remaining on station for 7 weeks at a range of 2500 nm and giving them submerged performance so good that contemporary AIP systems were simply not worth utilizing
    12. American BYG1 combat system + large and advanced sonar suite + Mk 48 torpedo gave the Collins a level of lethality and combat effectiveness that approached nuke subs- in their ability to detect, track and classify and engage stealthy targets
  9. Interesting to note that the French offered the nuclear barracuda to the Australians in 2015-16 but the Ozzies themselves rejected nuclear propulsion because it was not viable-
    1. Only LEU tech was on offer which required refuelling every 10 years- which is complicated as you have to complete the nuclear fuel cycle- Oz has no civilian nuke industry so the costs of establishing & running enrichment, conversion, fuel manufacture and spent fuel handling and storage just for the nuke subs are so high that it was never a realistic option
    2. Even if the fuel is imported Oz does not have the specialized infra and personnel to handle spent fuel- further increasing cost
    3. Having another nation refuel Oz subs posed unacceptable vulnerabilities - there is no guarantee Franco-Australian relations would be good for 50 years. Paris could refuse to refuel Ozzie barracudas if there was a conflict of interest- rendering them impotent. Even the threat of ceasing such support gives France immense leverage over Australia. Risk for sovereignty.
    4. Extremely poor submarine availability sailing them to France for full-cycle docking
  10. 4200 tonne Soryu Class
    1. Details are sketchy but in range and endurance Soryu is worse than the barracuda and Collins both
    2. The first 10 platforms were equipped with an AIP system (4x Kockums sterling engines) in addition to a DE system for a submerged endurance of 6000 nm without surfacing- very close to a nuke sub
    3. AIP systems require large oxidizer tanks which eat up space for batteries and fuel- significantly lower patrol range despite being larger than Collins
    4. Penalty on internal space for the crew- crew amenities are inferior to the Collins class
    5. The final two boats in the Soryu class use a diff propulsion layout beginning with Oryu the AIP system has been completely removed- Only diesel generators and Li-Ion batteries- significant improvement in performance over lead acid systems providing a level of energy density that essentially makes AIP redundant
    6. Onboard electricity generation capacity is 70% of Collins- so Collins can recharge her batteries faster
    7. Serious concerns about the safety of Li-Ion batteries in subs- in 2008 a Li-Ion equipped mini sub exploded and was completely destroyed- will be total loss of vessel at depth
    8. Japanese only require a 20 year life in their subs rather than the 30+ by RAN- has implications o the design from the grade of steel used to the quality of the welds
    9. Japanese consortium has no experience of constructing a vessel internationally
    10. Highly problematic option because of above reasons
    11. A former sub engineer Paul Greenfield noted- "Australia's future sub would require over 100,000 cells in some 500 modules and the life of 100,000 cells & a fleet of 12 subs- there is likely to be a failure that cannot be stopped or controlled with a catastrophic outcome."
  11. 4300 tonne Type 216 - essentially an enlarged Type 212 in service with Germany & Italy
    1. Good on paper but the largest sub TKMS ever produced was the 2200 tonne Dolphin class for Israel. This was to be the largest sub they had ever designed or manufactured. Brand new platform- Risk!
    2. Hybrid DE and AIP (methanol + liquid oxygen to drive a hydrogen fuel) could remain submerged for 2600 nm at 4 knots
    3. Equiped with Li-Ion batteries the DE drive gave the boat an additional 10400 nm range
    4. Indescretion rate 20%
    5. TKMS had to scale up the Type 212 to more than double it's size
  12. 5000 tonne Conventional barracuda (Short-fin Barracuda block 1A)
    1. Proven hull design of the Suffren, but use DE propulsion- required a complete redesign of the sub as all the internal spaces had to be modified
    2. No AIP, No Li-Ion but lead-acid batteries. But these were clearly not critical technologies for RAN. A large enough battery bank combined with a large enough electricity generation capacity can make the indiscretion rate so small that the advantage of AIP systems is minimal in real-world operations- How important is your ability to avoid snorkelling when this only takes a few minutes every 24 hours. Is it worth the substantial penalties you pay in range and endurance?
    3. By having a larger submarine and keeping the propulsion conventional the design had a massive range 18000 nm
    4. Generous crew amenities increasing effective endurance
    5. only design equipped with a pump jet instead of a propeller- higher top speed and a higher speed without cavitation
    6. 28 weapons on board for max fire power
    7. Tech challenge of converting nuke design to conventional remained substantial
SEA-1000 proposal- features like AIP, Li-Ion batteries, pump jet propulsion were not mandatory
1634581833981.png


For the Collins class even with old fashioned lead-acid batteries the size of the submarine alone provides substantial advantages in submerged performance if the indiscretion rate is prioritized. Li-Ion batteries can always be retrofitted at a later time when the risks were better understood. Safety concerns is why NG (Naval Group) chose lead-acid batteries. Short fin barracuda had the best range, endurance, kinematic performance and firepower. It would also be manufactured in Australia. One of the largest conventional subs ever built like the Collins for substantial performance advantages.

This still born attack class sub had the potential to be the most lethal and capable conventional sub ever created. The brains of a Virginia class SSN in a sleek and stealthy French body driven close to the speed of a nuke sub via pump jet propulsion but then why did the attack class program flounder?

Short answer: The deteriorating Sino-Australian relationship & the American decision to transfer nuke reactors to Australia.
Long answer:
Substantial advantages of nuclear propulsion which RAN prioritized as operational requirements. Chinese satellite intelligence is increasingly getting stronger. The Yaogan satellite constellation contains 30+ active EO imaging and SAR systems arranged in a staggered series of polar orbits. These sats make passes over the Western Pacific every hour or so playing a key part in PLA's wide area ocean surveillance system in their A2AD complex. They will pose a threat to any hostile (to China) sub operating near the surface- makes DE subs vulnerable to detection while they are snorkelling. In the wide open areas Ithe Pacific or Indian oceans it is not critical as by the time a Chinese asset is in the area the sub would have vanished but in heavily defended areas like SCS this will be an increasingly dangerous vulnerability- even AIP will not fundamentally address this issue. A nuke sub can stay deep throughout its entire 90 day patrol when an AIP sub would still have to regularly snorkel. The indiscretion rate for a nuke sub is 0.

From a legal angle:
The NG was never given a contract to build 12 subs! The contracts were structures in a way that they progressed from one stage to the next. SPA (strategic partnering agreement) was the framework for issuing actual contracts in various stages. Only once one program contract was completed would the next be issued to NG. Allowed the Ozzie Gov to keep its options open providing several off ramps if they no longer wanted to proceed for any reason. No guarantee that the govt would move to the next phase once one phase was over.

One of the other major advantages nuclear propulsion provides a submarine is the colossal amount of electricity a nuke reactor produces- 10x or more a DE sub, called the hotel electric power this is the spare electricity a sub has to use other than to move the vessel- sonars, computers. fridges, lights. In a conventional sub everything runs off the battery bank- it impacts submerged endurance. New systems of sub warfare will need more and more electric power. USN is developing a high energy laser for the Virginia class sub fired from the photonics mask what used to be a periscope this laser will be able to target drones and anti sub helis, to support underwater drone ops. In the very near future, a single sub may act as the mothership to a fleet of drones that will act as the boat's eyes and ears extending its sense of footprint dramatically- these will all require electrical power.

Australia needs bigger, more powerful boats than the attack class. Astute displaces 3000 tonnes more while surfaced while Block 5 Virginia is 2x the size of the attack class- carry more weapons, can steam faster, transit greater distances much more quickly and therefore remain on station longer. Pump jet equipped HMAS Attack could have reached 20+ knots top speed but doing so would have rapidly drained its batteries while a Virginia or Astute can steam at 30+ knots indefinitely. Both vessels have room for at least 10 additional weapons- more credible land attack capability.

Why were these advantages of nuke subs not realised in 2016 when the attack class was selected?
Canberra and Beijing relations have nose dived only recently and little hope of reversing trend. The problem of the nuclear fuel cycle from 2015-6 is now addressed by AUKUS. The reactor will arrive in a sealed steel box made in US (or UK) ready to be installed in the sub, it does not need to be refuelled until the sub is de-commissioned (single largest cost of operating a nuke sub). GE developed a HEU fuelled SG-9 reactor with a life of 33 years- the core will remain sealed throughout it's entire operational life. No Oz personnel will have to handle HEU fuel ever. After the life of the sub the still sealed box of the reactor will be transported to the US for disposal. With the American reactor tech Australia does not need to have a nuclear fuel cycle in order to have a nuclear submarine. Sits well with the NNPT as, under article 3, the use of fissile material for military reactor fuel by non-nuclear weapon states is not prohibited.


Fuel cycle:

1634588801664.png



Based on this understanding what are the implications for choices being made in P75I?

Ozzie experience clearly shows a large bank of lead-acid batteries with powerful diesel generators can be more effective than AIP. AIP provides close to nuke sub submerged range but comes at the cost of patrol range and crew comfort. Is IN simply suffering from brochuritis to be harping on AIP? I think not. They are targeting P-75I for defensive ops and are maximizing stealth (against an intruding Chinese sub) via long submerged operations close to India's shores while SSNs will go up to SCS and be the offensive arm of IN. Also longer submerged endurance will keep INs DE subs hidden from Chinese satellites.

The possibly explosive Li-Ion batteries are de-risked to some extent by insisting on it being operational in a submarine & the higher power density will also add to submerged endurance in a very compact form factor again aiding stealth. P75I could provide an exceptionally low indiscretion rate with the quietness of DE propulsion. However, a couple of questions remain:

1. At 20+ knots top speed & draining batteries fast while being chased they will not be able to outrun 30+ knots with unlimited endurance Chinese SSNs (even if noisier reactor & badly cavitating)- only relying on stealth to save the day but no recourse other than weapons once the cover is blown. How wise a choice is that?

2. With the mothership concept of operations how will a DE sub provide electricity for all collaborating manned/unmanned vessels & laser weapons? Is it future proof from a power generation point of view? The recent USS Connecticut collision with probably a Chinese XLUUV is only an indicator of a continually increasing threat of under sea drones.
 

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