April 16, 2021

Satellite Photo INS Arihant & Arighat Berthed Alongsid

Interesting information by Joseph P Chacko at frontierIndia. com titled Google Maps Show Indian [Arihant class] Submarines Berthed Alongside” of February 5, 2021:

The photo in question, showing INS Arihant and Arighant together, at right, berthed alongside the pier. (Photo reproduced from idrw . com December 18, 2020.) 

“The [Arihants ] are easily identifiable as the fins are located in the forward with the diving planes are fin mounted. Forward fin permits positioning of missile launchers aft. None of the the Indian conventional submarines have this feature

...Initially [what became INS Arihant] was conceived as SSN based on the [Soviet] Charlie1 class design 

...However, after the first concept design was made the requirement to make an SSBN post Pokhran 2 (aka II) in May 98, a decision was made to make Arihant as an SSBN. 

The objective was achieved with the design collaboration with Rubin design bureau in St Petersburg.” Much more

April 15, 2021

Gessler: Future Indian SSNs & SSBNs: Comment 1.

Following India's 6 Future Alpha SSNs - SSBN Protectors of April 7, 2021 Gessler made some learned and extensive comments on April 9, 2021. Pete has added some comments in [...] brackets. Here is the first of 3 Gessler instalments:

“@Pete. I'm sceptical about the figures of India’s future indigenous Project 75 Alpha SSN tonnage/displacement floating around in the media. I suspect those displacement figures (not only mentioned by Hindustan Times but many others as well) are from the same erroneous sources that also claimed that the S-3 boat (INS Arighat) the sister of S-2 (INS Arihant) would be considerably bigger and carry 8 missile silos. 

The photo in question, showing INS Arihant and Arighant, at right, berthed alongside each other and the pier. (Photo reproduced from idrw . com December 18, 2020.)

But satellite images (like this) of the Ship Building Centre (SBC) harbour at Visakhapatnam (Visak, most commonly pronounced & spelled Vizag) prove that both of the Arihant-class INS Arihant and INS Arighat are the same eg. Arihant class displacement 6,000 tonnes (surfacedconfirmed), length (116m) and size (Beam 11m, Draught 15m), and carry the same number of missile tubes, ie. 4. [See "Future of Indian Navy - Nuclear Submarines"]

Now don't get me wrong - I still am inclined to believe the 4th nuclear boat to be built by SBC (known in the media as the S-4* or S-4 Star) [see "Ships in class"] would indeed be considerably bigger than the Arihant-class, satellite images of a new submarine dockyard shelter constructed at Vizag which is up to 40m longer than Arihant's shelter substantiate the theory that a new, bigger boat is around the corner - and it definitely can't be the S-5 yet. So it has to be the rumoured S-4* SSBN, with perhaps 8 silos.

Nuclear expert Hans M. Kristensen's observation of the same summarized in his tweet, though he speculates this to be intended for the S-4 itself (3rd nuclear boat), not the S-4*. Personally, I would think all three Arihant-class SSBNs will be of the same dimensions, it would not make any sense to have the last boat in class to be substantially different than the others.

The S-4* on the other hand might make sense as both a test platform for new, larger equipment that may eventually find use on the still larger S-5 class down the line, once the systems mature after at-sea testing on this boat. The Arihants would have to be at sea (or in refit), delivering on the deterrence role, you can't ask them to come off their vitally important duties to function as test platforms for new stuff - the S-4* might make a lot of sense in that respect. 

Another reason to be sceptical about the Alpha's displacement figures would be that pretty much all available sources (unless I'm misremembering) quote the Arihant-class boats' surfaced displacement as approx. 6,000 tonnes

So if the Alpha indeed turns out to 'Arihant without silos' then there's no way it'll also be 6,000 tonnes surfaced. The Alphas will have to be 5,000 tonnes [surfaced], but even that is speculation.

So personally I'll hold my horses for now regarding the displacement figures."

[For comparison see the 6,000 tonne (likely submerged) 100m long, Brazilian future SSN Alvaro Alberto (SNB or SN-BR). Implicitly its displacement may also be around 5,000 tonnes surfaced.] 

Tomorrow Gessler's 2nd informative Comment will appear. 

April 14, 2021

Yuan-submarine (LABs & LIBs) propulsion estimates

Following Lithium-ion Batteries: South Korean & Chinese Subs of April 9, 2021, Anonymous on April 13, 2021 kindly provided these comments and calculations (with some editing by Pete) regarding battery propulsion for China’s Yuan-class submarine:

The advertisement for China's Winston Battery WB-LYP10000AHA Lithium-ion Batteries (LIBsindicates the average on-board consumption of a Yuan-submarine, when not moving, is some “38kW/h” meaning that its hotel load is 38kW. 

The total energy of Lead-acid Batteries (LABs) (assuming they are 400 tonnes in weight) in the Yuan-class seems to be around 11 MWh or more. The Chinese make the incredible claim the Yuan-class using LABs can stay under water for 12 days! [1, 2] Such a LABs-based submarine does not exist. A capacity of 31 MWh, 3300 nm over 33 days for Yuan (LIBs) also looks like perfect nonsense. 580nm over 6 days looks more reasonable [3].

[1] A Japanese ton is the same as a metric tonne, ie. 1,000kg. This calculation example uses data of a Japanese GS-Yuasa LAB, type MSE-3000 (weight = 212kg, capacity = 3000 Ah, voltage = 2V). As the energy of a type MSE-3000 is 6 kWh ( = 3000 Ah x 2V) , then energy of 400 tonne of MSE-3000 is 11.3 MWh ( = 400 ton/212 kg x 6 kWh). Then total hotel load per day is 0.912 MWh/day (= 38 kW x 24h). Endurance is 11.3 (MWh)/0.912(MWh/day) = 12 days.

[2] Generally, the average hotel load of diesel submarine is around 150kW. Maximum (90% discharge depth) and repeatable (30% discharge depth) endurance of a Yuan-class using LABs might be 3 days or less.

[3] On LIBs, if the hotel load and propulsion output at 4 knots are 150kW and 50kW, respectively, total output per day (= (150kW + 50kW) x 24h) is 4.8MWh/day. Then endurance and distance, at 4 knots, is 6 days (90% of discharge depth) and 580nm ( = 4knots x 24h x 6 days). And endurance when not moving (= 0 knots) is 7.8 days (=31MWh / (150kW x 24h) x 0.9).

April 13, 2021

GhalibKabir on Future Indian Alpha SSN issues

Following India's 6 Future Alpha SSNs - SSBN Protectors of April 7, 2021 came the blessing of a veritable avalanche of good comments from Anonymous, GhalibKabir, Gessler and Arpit Kanodia. Rather than attempt to summarise each comment (obscuring meaning and context). Or try to respond point by point (which would fill 10 pages/5 articles) I'll republish the comments. I'll also add some lengthened weapon designations,  comments in [...] brackets and extra links.

I'll start combining GhalibKabir’s comments of Apr 8, 2021:

“Pete, I think we discussed this way back in 2019, similar to the Chinese Type 091 (NATO (Chinese Dynasty) reporting name "Han" class) SSN. The future Indian Project 75 Alpha SSN will likely (initially) use a slightly uprated Arihant 40% HEU PWR (uprated from 83 MWt to 100 MWt) implying electrical power uprates to 16.7 MWe from a maximum of 13.8 MW presently) (the rule of 1/6 for naval reactors vs 1/3 for land based). 

Peter Lobner got it right with his 100 MWt prediction I think. [See Peter Lobner "Marine Nuclear Power 1939-2018: Part 5, China, India, Japan & other nations" (July, 2018) page 159 (Table) and page 163 at https://lynceans.org/wp-content/uploads/2018/07/Marine-Nuclear-Power-1939-2018_Part-5_China-India-Japan-Others.pdf about 50 MB, 294 pages

The S-5 class future full size Indian SSBN could see a single Soviet/Russian OK-650 reactor [which India may have designated the CLWR-B2 Compact LWR - see right sidebar] derivative as the bigger SSBN will need 25 MWe or more capacity to be available implying a 160-170 MWt OK-650 [even 190 MW and see also ] class reactor.

However, SSN reactor dynamics are likely to be different as the rapid 'power up power down' variation demand on the SSN reactor for 'sprint chases' will be much higher than an SSBN. The Arihant class' or even the S-5's likely speed requirements could stay between 22-24 knots while the Alpha SSN will need burst speed capability of 35 knots and the ability to do 28-30 knots frequently and consistently... (like China's current Type 093 Shang class SSN for instance). 

Also I think INS Chakra II elements with Arihant base is the most likely in SSN Alpha and not Barracuda or the Alvero Alberto [aka "SN-BR"] Brazilian Scorpene SSN (though some learnings will cross over in welding, silencing, reduction gear design etc.) [Also the future Chakra III might influence the Alpha SSN. "India and Russia, March 7, 2019, signed $3Billion deal to lease another Akula SSN, dubbed Chakra IIIshould be delivered to Indian Navy 2025].

I do hope India is able to leverage [France's] Thales and [Israel's] Rafael under water suites expertise to equip the SSN with good sonar suites and combat capabilities."

[The Russia-India lease deal means] INS Chakra II cannot be used in offensive war. It cannot be armed with any missile ranging > 290 km i.e. original MTCR restrictions apply (unless I am gravely mistaken)...it can help in case of open war, but will be limited to defending with torpedoes and such short range missiles as to be of very limited utility indeed....plus the sonars and combat suites are very old as well....

I think a vertical launch system (VLS) [on the Alpha SSN? Within a 6,000 tonne (submeged) displacement limit?] combo with Horizontal launch capability could be better... 24 Tri-packed Nirbhay sub-sonic SLCMs in 8 VLS with 20+ combination of Varunastra Torpedoes and BrahMos SLCMs are the most likely combos..

Also while a propulsor pumpjet is desirable and is being tried, I think a conventional 7 blade screw is likely for the first 2 Alpha SSNs at least. Like the Chinese Typo 091 SSN in 1975, the focus first should be to get a couple of Alphas out and test them. Then we can see and make real progress, instead of an unhealthy obsession with 'perfect profile' product launches.

The Type 091 used a 60 MWt inefficient PWR that delivered 8 MWe and was very radiation leak prone. The key difference being the PWR was a LEU (thanks to the Soviets screwing the Chinese over [Soviets were worried Mao was prepared to risk dragging the Soviets into nuclear war against US and Taiwan]. China was left with minimal uranium supplies and also a loss of nuclear and submarine expertise after China's Cultural Revolution). India has been a HEU navy.

Good that [India's Chief of Defence Staff, General] Bipin Rawat, Doval and co were able to prevail on the SSNs after 3 years of wrangle at North Block" [ie. wrangling at the Ministry of Finance, New Delhi].

April 9, 2021

Lithium-ion Batteries: South Korean & Chinese Subs

Following their briefing of March 26, 2021, on Japanese submarine Lithium-ion Batteries (LIBs), Derek Woolner and David Glynne Jones have kindly provided information  on LIBs, summarised as follows: 


LIBS to be on SK's new conventionally (diesel-electric) propelled cruise and/or ballistic missile submarines (KSS-III SSBs)

SK is building its 9 x KSS-III SSBs in 3 “Blocks” of 3 each. The first 3 (KSS-III Block 1s)  will have current technology Lead-acid Batteries (LABs) and fuel cell Air Independent Propulsion (AIP).

For KSS-III Blocks 2 and 3 SK undertook a research process which determined LIBs were the best way to go. Blocks 2 and 3 will have reportedly use Samsung SDI LIBs. See further details here and hereLIBs development for SK subs may have been ongoing for 5+ years.

SK’s 3 x KSS-III Block 2s will be [launched 2022-23 and 24 then steadily commissioned] in the mid-late 2020s. They will be equipped with LIB main batteries and fuel cell AIP. The Block 2 LIB main battery system will be approximately double the effective capacity of the Collins class submarine main battery but less than half the weight.


LIBs on Chinese Yuan-class conventionally propelled attack submarines (SSKs). 

Rounding out East Asian LIB developments. There have been unconfirmed reports, since 2015, that China has been planning to build a LIB-equipped evolution of the Yuan-class Type 039 SSK. 

There are strengthening indications that China will build a significant number (> 20) of Type 039C LIB-equipped submarines in the mid-late 2020s. See https://www.globalsecurity.org/military/world/china/yuan-units.htm (a limited free looks paysite.)

About Derek Woolner and David Glynne Jones 

Derek is co-author of the 2008 classic The Collins Class Submarine Story: Steel, Spies and Spin . He is a previous Director of the Foreign Affairs and Defence Group in the Parliamentary Research Service.

David is an independent advocate for the adoption of renewable energy technology across all sectors of the Australian economy. He is currently assessing the implications of emerging advanced battery technology for electrification of the Australian transport sector.

Their blog-website is Woolner and Jones. 



Regarding South Korean LIBs

On the basis of Japanese sub JS Oryu's launch in October 2018 and the first KSS-III Block 2 perhaps being launched in late 2022, SK LIB development may be 4 years behind Japan’s. SK’s KSS-IIIs will not be typical SSKs (unlike Japan’s Soryus and Taigeis or SK's KSS-Is and KSS-IIs). SK’s KSS-IIIs are dedicated carriers of vertical launch systems for cruise or ballistic missiles - making these subs SSBs].

See SubMatts article of February 5, 2016, China's Yuan Subs May Adopt LIB Batteries

Regarding Chinese LIBs

China's Winston Battery company (aka "Shenzhen Smart Lion Power Battery Limited" and/or "Thunder Sky") may be (or is) developing a 335kg WB-LYP10000AHA LIB for submarines (see below). 


The following Winston LIB Battery entry is dated "6 years ago", hence may be dated 2015. See https://gwl-power.tumblr.com/post/106634862416/winston-battery-wb-lyp10000aha-in-large or here and reads:

"Winston Battery WB-LYP10000AHA in large submarines"

"The technical information gives some ideas about the size of the battery pack for the Yuan-class of diesel-electric submarines to be equipped with an air-independent propulsion system (AIP) powered from large battery banks.

The battery pack consists of 960 pcs of the WB-LYP10000AHA cells making the total energy of 31MWh. The lithium battery is saving some 260 tons of weight against the original lead-acid pack. With this pack the Yuan-class (B-class) diesel-electric submarine can drive 3300 nautical miles or it can stay under water for 800 hours (33 days). This indicates the average onboard consumption of the submarine when not moving is some 38kW/h." 


Submaine LIBs may already be aboard one or two of Chinese Yuan class (039A) test submarines or on China’s dedicated large test sub (known as the Type 032 “Qing” class). The the Winston LIB concept might additionally be a marketing idea to attract foreign finance. It is possible Russia may be interested in the Winston LIB concept.


April 7, 2021

India's 6 Future Alpha SSNs - SSBN Protectors

These are my comments following March 31, 2021's "India's future 6 SSNs over 3rd Carrier: Internal Leverage." 

India has been discussing the development of 6 x SSNs, now dubbed "Project 75 Alpha" since the 1990s. There has been endless talk and breathless Indian media reporting that these Indian SSNs (lets call them Alphas) will be built "very soon" for the last 15 years. 

India, like most nuclear submarine-nuclear weapon powers, has had to juggle needs to fill out all 3 "legs" of the nuclear triad. That means India has simultaneously developed  nuclear weapons dropped by aircraft and mounted on long range land based missiles. SSBNs with their SLBMs, are the last, hardest and longest to develop, leg of the Triad. Meanwhile India has been talking about developing Alpha concepts before it can get around to "cutting steel" - noting the highest priority of Alpha SSNs is to protect SSBNs.   

INS Chakra II and eventually III

India already has been transferring technology from its 30 year old design Russian built Akula SSN known as INS Chakra II (ex Nerpa) (see artwork below) Chakra II has been under 10 year lease since 2012 from Russia - so lease expiration may be in 2022. The lease may be extended if Russia is unable to supply a later model Akula (unofficially named “Chakra III”) by about 2025.  Chakra II and then III hulls were designed in the early 1980s may not be carrying torpedoes or anti-ship missiles permitting them to be truly operational in defending Arihant-class SSBNs. I'm aware of no reports of  Chakra II regularly pulling out of its base at India's Eastern Naval Command HQ - Visakhapatnam or returning to "Visak". So Chakra II's main value may be limited Indian crew training and/or Russian  transfer of technology (ToT) to India. 

Training and ToT would include Chakra II's 190MW OK-650 reactor which may be running in place while not actually moving the sub. An Indian variant of the full 190MW power of the OK-650 reactor will be more than adequate to power India's future 13,500 tonne (surfaced) S5-class full size SSBNs (see artwork below). Significant updated variants of the OK-650 already power Russia's latest Borei/Borey class SSBNs (see right sidebar).

Meanwhile Indian nuclear crew training continues on INS Arihant and soon Arihant's sister-sub INS Arighat

French Barracuda SSN and K15 Reactor Value

India’s 6 x Alphas may have some features of India’s 8,140 tonne Chakra “II”. But India talks more of a 6,000 tonne Alpha that would, of course, have many design differences to a 8,140 tonne Chakra II. India understandably has an interest in French Naval Goup ToT from its 5,300 tonne (submerged) French Barracuda class very modern SSN which is likely to be much quieter than 38 year old hull technology Chakra-Akulas.  Naval Group may be enticed to release more Barracuda details if this is packaged with India purchasing 6 x Scorpene (AIP) SSKs under the endlessly discussed and delayed Project-75I

While a Russian OK-650 reactor would be too large for a 6,000 tonne Alpha Russia and India may want to investigate the Barracuda’s K15 reactor. Obtaining K15 details from France via India would constitute an intelligence coup for Russia. For India an enlarged, more powerful, variant of the K15 may be sought. The K15’s main limitation being its need to refuel every 7-10 years. India would value a fuel core more at 15 years or even better, 35 years (whole of submarine life).

Alternatively India may rely on a highly modified variant capable of 100MW derived from  the 83MW reactor used for INS Arihant (more see.

Alpha SSN Protection of SSBNs

The Indian government support for building 6 Alphas in India is not only a navy matter. A (or the) major task of the Alphas will be to protect India’s growing force of SSBNs. See this generalised and very useful description of India's future nuclear subs.  These SSBNs (so far only the 2 small Arihant class) will form the most secure and potent second strike arm of India’s nuclear triad. Two more slightly larger Arihants are planned - making 4 Arihant small SSBNs (aka "Baby Boomers"). The Arihants however cannot accommodate SLBMs large enough to hit the capital, Beijing, of India’s (likely) enemy China. 

A more effective second strike SSBN arm will come with the full size “S5” SSBNs (see artwork below). These S5s, which may be launched from the late 2020s/early 2030s, will be able to accommodate 12 to 16 larger, longer range, desirably "K6" SLBMs capable of hitting Beijing.

The Arihant class and INS Chakra are current. Third one down is a possible shape and comparative size of a future Indian 
Alpha SSN below that is the possible shape of a future, larger Indian SSBN class (known as S5). (Artwork and captions courtesy

H I Sutton's, Forbes article of Feb 23, 2020).

Bastion Protection of India's SSBNs 

India's Arihant SSBNs are believed to be noisier than Russian or Western ideal SSBN noise levels and there are no new Alphas to protect them. So India's Arihants may need to be Bastion Protected in the Bay of Bengal by India's P8 MPAs, other jet aircraft, helicopters,  surface naval ships, undersea sensors and many other sensor and weapons platforms. 

It remains unknown whether India's leased Chakra II is armed, and therefore able to provide credible protection to just one Arihant. Even if a "newer" Chakra III is leased these Akulas are early 1980s hull designs, so liable to be comparatively noisy. They would need to be able to detect far quieter Pakistani AIP-Agosta-90Bs and late model Pak-AIP-Yuan SSKs as well as Chinese AIP-Yuans and Chinese SSNs.

India's first Alpha may be delivered to the Navy in the late 2020s and will need around 3 years of testing/training/working up to be fully commissioned in the 2030s. India will then probably require 2 more Alphas to form a credible protection force of 3 Alphas (noting rule of thirds). This may need to coincide with full commissioning of the first S5 full size, and quiet, SSBN.

So India may only have a fully operational force of 3 Alphas and 3 S5s in the late 2030s.