December 31, 2021

Launch of S4: India's 3rd Arihant class SSBN: Reactors.

Gessler posted details here on December 30, 2021 concerning the reported November 2021 launch of the Arihant class SSBN S4. Gessler reports:

Launch of S4 is "a pretty significant development in the region:

India seems to have launched the 3rd nuclear boat (hull S4) of Arihant-class [in November 2021]:


I don't have a Janes' subscription so can't delve deeper into the details contained therein. However, commercial satellite imagery [above (see earlier imagery of the S4 shed above provided by Ghalib Kabir in August 2021 and November 2018)] obtained by open-source intelligence (OSINT) contributors on Twitter seems to validate the notion that the 3rd & 4th boats of the class will indeed be bigger than the first two (also corroborating nuclear expert Hans M. Kristensen's extrapolation based on size of the submarine shed [seen lower center] deployed a few months ago, which I've talked about previously on here):

Further details are still awaited but if the earlier literature about the "Arihant Stretch" class holds true, the 3rd & 4th boats could indeed have 8 x missile silos, for either 8 x long-range SLBMs (like K4 or K5), or up to 24 x medium-range SLBMs (like K15) with a triple-pack in each silo - or any combination thereof, depending on requirements.

In the late 2030s when these boats might take one an SSGN role, it could mean up to 40-48 land-attack cruise missiles on the "Stretch" boats like I previously speculated on here.


Note that S4 is the 3rd Arihant class SSBN launched:

-  S1 was a land based prototype reactor designed for the 4 Arihant class SSBNs known as S2, S3, S4 and S4*

-  The first 2 Arihants, already launched are S2 (INS Arihant) and S3 (INS Arighat), each believed to displace 6,000 tonnes and have 4 full sized SLBM silos. S2 and S3 are powered by a reactor rated at 83MWt (where t = thermal). Using a rule of 1/6 to convert MWt to MWe this implies available electrical power of 13.8MWe for the submarine's propulsion and non-propulsion "hotel load" electrical needs. Hotel load includes life sustaining electrical uses such a air and drinking water regeneration as well as cooling air conditioning for the crew and to cool electronic equipment.

Above courtesy H I Sutton at Covert Shores who produced an article yesterday which includes the above artwork (can be enlarged here) comparing S2 and S3. While H I Sutton estimates the length of S2 and S3 as 110m vs 130m for S4 India's  The Wire indicates a Janes' estimate of 111.6m vs 125.4m. The Wire, perhaps also drawing on the Janes' report even indicates S2/INS Arihant uses 600 tonnes of Russian sourced Titanium in its pressure hull.    

The final two Arihant class SSBNs, S4 and S4*, are believed to displace 7,000 tonnes, have 8 full sized SLBM silos and possibly use a reactor uprated to 90MWt = 15MWe.

It is unknown whether some or all of the Arihants use a pumpjet (developed by India's DRDO) instead of a propeller.

In the New Year I (Pete) will present Gessler's second December 30 commentI'll also comment more extensively on the implications of S4's launch and on the broader Arihant class.

Happy New Year


December 29, 2021

Initial AUKUS Sub Objective: Wedge Aussie Opposition

Thank You Bureaucratus Lex for his December 24, 2021 Christmas Story

Luckily Santa, riding his Submerged Sleigh, has imposed further Non Disclosure Agreements "NDAs" on his Elves and Reindeer prohibiting them from revealing a major secret. I (Pete) revceal it now. 

Australia's current Prime Minister (Holy ScoMo Morrison's) AUKUS sub plan is initially a pre-2022 Election wedge tactic aimed at his political Opposition:

A. the Greens (totally anti-nuclear) + Labor Left (anti-US alliance)


B. the Labor Centre Right (pro-US alliance and pro-submarine building jobs).



Early in 2022 Morrison will summon his little Australian Reporters yet again. AUKUS sub aficianados will remember Morrison successfully selected Reporters to doorstop Macron into starting the "I know Morrison lied about submarines" play act. 

This time Australia's current Prime Minister Morrison will instruct his Reporters to ask A and B "Are nuclear submarines for Australia a good idea?"  

A and B will be impelled to disclose to their voter constituencies A's rejection and B's unconvincing acceptance of ScoMo's nuclear AUKUS Sub Surprise. 

You saw this AUKUS Nuclear Sub Wedge Theory first at SubMatts on September 22, 2021.

Happy New Year


December 28, 2021

Second Hand Submarines No Solution for Australia

My thanks to Anonymous, who on December 24, 2021, raised the Japanese confidentiality problem (which would include Japan's special HY-156 pressure hull steel) of Japan selling its submarines. This is in the context of Bradley Perrett's December 23 suggestion that Australia could relatively quickly and simply buy second-hand Japanese Oyashio class submarines to resolve some of Australia's incredibly complex submarine problems. 

Bradley suggestion, while attractive to some, falls down for many reasons, including:

-  the Oyashio subs (commissioned 1998 - 2008) are as old as the Collins (commissioned 1998 - 2003)

-  Japan is undertaking mid-life upgrades to its newest 7 Oyashios so that they can remain effective operational subs for the Japanese Navy. They are being upgraded at great expense rather than simply depreciating with age. That being the case Japan will not part with its Oyashios.

- the Japanese military and political establishment lost face when the Australian purchase of Japanese subs, promised by Prime Minister (PM) Abbott in 2014, was ignored by PM  Turnbull, when Australia chose France in 2016. This means Japan is unlikely to risk being played by Australia again.   

- the suggestion that Australian owned Oyashios could be overhauled in Japan would be unacceptable for Australian strategic, logistical, union and other political reasons.

-  Japan's subs are too short range for Australia's environment. Japan's longest patrol distance is only from southern Japan to the the northern tip of the Philippines. While Japan does not publish the range of its Oyashios they actually have a range of 6,000nm thus rendering them useless for most Australian mission needs. 

-  Collins have and need twice the range at 11,500nm. This range is for the 6,000nm to transit to-from their operational areas north of Australia. Then at least 5,500nm to operate on station.

-  if Oyashios were used in Australian service they would need to be heavily and expensively modified to take the US-Australian electronics suites used on the Collins and which is to be  used on Australia's future nuclear subs. That includes the AN/BYG-1 combat system of sensors, databases, workstations and weapons (especially the Mark 48 torpedo).

-  Bradley's suggestion "The more submarines in service, even if they are diesel powered, the easier it will be to create crews" doesn't follow. Australia finding twice as many crews to operate not one but two types of conventional submarines while simultaneously training other Australian crews to operate the future nuclear subs would dilute limited defence resources.

A more viable solution remains the Collins' mid-life overhaul aka life of type extension (LOTE). The biggest limiter on submarine lives is metal fatigue of the pressure hull caused by the number of immersion cycles. Each time a submarine dives its pressure hull contracts and then it expands as it returns to the surface. The Collins' pressure hulls have spent more than their years would suggest out of the water due to long diesel overhaul periods. So they have a lot of life left in them. If the LOTE includes replacing the Collins main defect, the overhaul-intensive Hedemora diesels, with the world's most common submarine diesels (built by MTU) then the Collins could well operate efficiently out to 2040. Note that Australia recognised the value of MTU diesels in 2019

December 16, 2021

S Korean nuke sub Reactor likely to be French K15 Variant

India's Bharat Express News December 14, 2021 carries the New York Times (NYT) December 13, 2021 article "South Korea has long wanted nuclear submarines. A new reactor could open a door." without readers having to subscribe to NYT. NYT's article is reproduced by Bharat Express here


South Korea is leaning toward a LEU reactor solution perhaps initially on a South Korea SSBN - which will be based around the ballistic missile submarine KSS-III SSB. It is not surprising South Korea has long been in talks with France (since 2017 if not earlier) about South Korea building a variant of France's K15 LEU reactor. The K15 is on France's Triomphant class SSBNs and, in slightly smaller form, on the France's Barracuda-Suffren class SSNs. 

In Submarine Matters’ “South Korea seeks Submarine Reactors from US and RUSSIA” of October 22, 2019 South Korea may have concluded it is better to buy an existing submarine reactor or at least a ship reactor than totally reinvent a submarine reactor. 

Since 2017 (if not earlier) South Korea has been considering France’s new Barracuda SSN with its K15 (aka K 15 aka K-15) reactor. With North Korea's buildup of nuclear weapon and missile capabilities South Korea, in October 2019, has been testing any increased US willingness for South Korea to explore nuclear propulsion options. 

The Triomphant-class's 2(?) x K15s and Barracuda's single K15 reactor stands for 150 MWt  power which translates to a total of 30 MWe electrical power (for the French Barracuda’s non-propulsive electrical services hotel load + propulsion).

"In October 2017, the [South Korean] Navy commissioned the Seoul-based Korea Defense Network to conduct a five month study on the feasibility of developing an indigenous nuclear-powered attack submarine. The think tank reported in March 2018 the results to the Navy, suggesting the service build a nuclear attack submarine along the lines of the French 5,300-ton Barracuda-class sub. The French sub is fueled by low-enriched uranium."

Now that the US and UK have given the green light to supplying Australia with a reactor under the AUKUS deal it is conceivable that France may want supply just the Barracuda’s K15 reactor or transfer technology (including a reactor design) for South Korea to incorporate in its 4,000+ tonne KSS III Batch III building program. 

The Barracuda’s K15 reactor has the:

-  political/regulatory advantage of using LEU ie. less than 20% U-235 which South Korea sees as not being restricted by the NPT or nuclear Safeguards Agreements. This is compared to the political sensitivities and anti-proliferation regulatory restrictions (up until September 2021's AUKUS deal) placed on exporting/importing US and UK HEU submarine reactors. The UK/US reactors use weapons’ grade HEU of 93-97 percent (see p. 20)

-  technical advantage of being built for a submarine of just over 5,000 tons, ie. in South Korea's KSS III Bach III weight bracket. While the 
KSS III Batch II with 10 x VLS silos  has diesel-electric (also AIP) propulsion the proposed KSS III Batch III may eventuall have 12 to 16 VLS silos requiring an unusually large propulsion solution. Nuclear has been the solution for SSBNs built by the US, Russia, UK, France, China and India. 

-  Also Naval Group's assistance to Brazil to create a SSN, known as Alvaro Alberto, is highly relevant to the South Korean SSN (aka KSS-N) project, Alvaro Alberto's projected launch year (2029) and commissioning (2032-2034) may occur in the same timeframe as the South Korean SSN project.  At Submarine Matter’s 2015 article see the subheading "Brazilian Nuclear Submarine (SN-BR)” There currently appears to be expectations that SN-BR will be around 100m long and 9m wide. This coincides with France's Barracuda SSN dimensions of: 99.5m long and beam: 8.8m.” 

-  So a A K15 variant first mounted on a South Korean SSBN by the early 2030s may be followed by mounting a K15 reactor variant on a South Korean SSN by the mid 2030s. In terms of vertically launched cruise or ballistic missiles the KSS Batch I features 6 VLS tubes, each with one missile. The KSS III Batch II may feature 10 and the KSS III Batch III perhaps 12 to 16. 

South Korea's neighbour Japan (a part strategic competitor of South Korea) is observing South Korea's interest in nuclear propulsion and ever larger submarines.

India, already having SSBNs, is interested in building 6 x Project 75 Alpha class SSNs with specialised SSN reactors. India is naturally talking to France's Naval Group. Naval Group is already  helping India build the 6 Kalvari-class Scorpenes, and bidding for India's 6 x AIP diesel-electric Project-75I SSK competition. Naval Group produces all of France's SSNs and SSBNs. So India can have far ranging discussions, on many topics, with Naval Group.

December 11, 2021

Advising Dictatorships on Democracy Disruption Methods

Now that Pete and I have won an equal opportunity gig as advisers to dictatorships (chiefly Russia and  China) on bigger, better disruption strategies, we seek suggestions from you our fawning readers.

1. Russia's idea of Belarus driving refugee's into democracies bordering Belarus (ie. Ukraine, Poland, Lithuania and Latvia) shows promise and professionalism by Russia's FSB and GRU. 

2. Burma's Army drove the Rohingya Muslim minority into Bangladesh, India, Thailand and Malaysia. 

Burma's much larger neighbour China may consider driving Muslim Chinese into the 'Stans on China's western border - not to mention Chinese Muslims into India. That is, as long as this forced migration strategy didn't blowback into China, in terms of increased Islamic terrorism in China and terrorism against Chinese government and commercial forces newly flowing into Afghanistan.

Tomorrow (Tuesday) we advise China on better places to put its bases in the Pacific Ocean.

P&P Inc

December 8, 2021

Turkey's 214TN "REIS-2" Submarine Project: Special AIP.

Clive Dorer, on December 1, 2021, made interesting comments on Turkey’s Type 214TN "Reis" program (aka "REIS-2"). This is particularly on the Reis class’s tailored PEM Fuel Cell air independent propulsion (AIP) arrangement.

A lengthened Type 214 - probably like Turkey's 214TN. (Photo courtesy WayBackMachine)

Clive comments:

“I recently stumbled on this interesting Defence Turkey article concerning the Turkish Type 214TN "Reis" program, or more usefully called, as the article explains, "REIS-2"

It has a number of interesting nuggets re construction methods, hull strengths and supply engagement issues (eg: design flaws, pressure hull plates coming from Austria as local industry could not produce HY100 to the required standard).

Also some great insights into the development revisions of the design, with the final design signed off in 2017 being over 2M longer than the original design, and largely detached from the length published in the glossy brochures.

But the bit that grabbed me was that the final design increased the number of the AIP’s metal hydride (MH) (a safer way to store Hydrogen) tanks from 6 x 6 (6 rows of 6 tanks each) to 7 x 6. This is a substantial increase (c. 16%) which PRESUMABLY will extend AIP operational windows.

Diagram of a PEM Fuel Cell AIP system (From a 2014 Submarine Matters Intelligence (SMI) report).

I say presumably because, although the article isn’t very clear, its implied the liquid Oxygen (LOX) storage is unchanged. This is open to interpretation, but made me wonder if, for example, there are consumption ratios between the two component fuels that change under usage scenarios - EG: does running the AIP’s Fuel Cell Proton-Exchange Membrane (PEM) at very low or very high power output affect the ratio of Hydrogen/O consumption. If so that would inform some interesting speculation on the mission profile [keeping an eye on the Russians, Greeks, Syrians and Israelis?] the Turks envisage for these new boats.

The answer may lie in whether PEM's can be "throttled" intra-cell by varying fuel flow thereto, or if they only really run in binary state (on/off) and the power provision is governed by varying the total number of cells in use. A lot of digging and I've found a lot of contradictory information on this. It seems fuel-cells in general CAN be throttled, but they do have a specific peak-efficiency point, and in the Submarine context of seeking maximum power extraction, the question is left hanging.

On balance I suspect that LOX capacity HAS increased inline with MH, and the author just didnt make this point crystal clear (or didnt know) but the general question of how PEM's are governed/throttle on subs, still stands.

It also begs the question of whether the Turks:

(a) want longer endurance or

(b) need to compensate for hotel load of their indigenous systems. 

Or both. Of course, this we'll never know, nor does it really matter, but fun to speculate.

Finally, it made me wonder if anyone had any idea of the number of tanks in use on the very comparable (in terms of displacement) Singaporean 218SG Invincible-class submarines - which are not yet operational. In other words, is this the extra capacity in the Resi-2 really novel, or not.

Extra 214TN Reis class Build Details 

from Turkish language Wikipedia

Type 214TN submarines of Turkey’s Reis class submarines being built.




Laid down


Estimated Delivery
to Turkish Navy

Built at.

2009 6 Ships
2014 4 Ships
2020 +2 Ships

S 330

TCG Piri Reis

October 2015

December 2020

2022 (Forecast) [12]

Gölcük Naval Shipyard

S 331

TCG Khidr Reis

2023 (Planned) [12]

Gölcük Naval Shipyard

S 332

TCG Murat Reis

2024 (Planned) [12]

Gölcük Naval Shipyard

S 333

TCG Aydin Reis

2025 (Planned) [12]

Gölcük Naval Shipyard

S 334

TCG Seydi Ali Reis

2026 (Planned) [12]

Gölcük Naval Shipyard

S 335

TCG Salman Reis

2027 (Planned) [12]

Gölcük Naval Shipyard

December 5, 2021

H I Sutton on Soviet/Russian Titanium Submarines

Petra and Pete thank JB from Texas for drawing attention to the following excellent
H I Sutton video:

Titled "Titanium Submarines: The Soviet Secret Which Shocked The West (Really)" 

dated November 28, 2021, here and below:


December 1, 2021

Reuters Investigates "Battle for Taiwan" Many Submarine Mentions

A brilliant, long, Reuters investigation of the China threat to Taiwan and ways to counter it, including Taiwan's use of submarines.

Part One: By David Lague and Maryanne Murray published Nov, 5, 2021 at

Titled “China’s quest to rule Taiwan has already begun with a campaign of “gray-zone” warfare. Here is how military strategists believe the struggle might play out.” With terrific graphics and excellent research.

Some Part One excerpts:

Tokyo, one of America’s closest allies, has also been reticent to get involved. Japan operates one of the world’s most advanced conventional submarine fleets. The idea of helping Taiwan was informally discussed in Japan but was dropped out of concern over how China might react, according to two senior defense ministry sources in Tokyo.”

“One reason for Japan’s hesitancy is fear of the economic consequences of offending Beijing, said retired Vice Admiral Yoji Koda, a former fleet commander of the Japanese Maritime Self-Defense Force. Japanese companies that would stand to lose business in China for helping Taiwan are a powerful lobby, Koda said.”

"Reuters found at least 12 foreign engineers who said in interviews or on social media that they had worked on the submarine program or worked for Gavron in Taiwan.

...[Taiwan] also succeeded in hiring engineers, technicians and former naval officers from at least five other countries: Australia, South Korea, India, Spain and Canada. Based at a shipyard in the port city of Kaohsiung, the experts have advised the Taiwanese navy and state-backed shipbuilder CSBC Corporation Taiwan, the company building the new submarines.

... a mix of young and veteran submarine experts – had experience working on advanced submarine programs. These included the S-80 built by Spanish state-owned shipbuilder Navantia and Britain’s nuclear-powered Astute-class attack subs built by BAE Systems, according to the recruits’ social media profiles.

...According to two sources in Taiwan, Lockheed Martin Corp is providing the subs’ combat system, which integrates and displays sonar and other sensor data to allow commanders to engage targets. Raytheon Technologies Corp is supplying the sonars, the sources said."

Part Two: Published Nov. 29/30, 2021 at .

Titled: “Taiwan has stealthily recruited expertise and technology from around the world to build a submarine fleet to serve as a deterrent against a Chinese invasion. Risking Beijing's ire, defense companies and engineers from at least seven countries are helping the diplomatically isolated island.”

Some Part Two excerpts:

"...For Beijing, success [in taking over Taiwan] would translate into a commanding strategic position in Asia, undermining the security of Japan and South Korea, and allowing China to project power into the Western Pacific."

"...For the American alliance, a Chinese takeover of Taiwan would be a devastating blow. At a stroke, the United States would lose its status as the pre-eminent power in Asia, according to most U.S. and regional military experts. If America were unwilling or unable to defend Taiwan, its network of allies in the Asia-Pacific – including Tokyo, Seoul and Canberra – would overnight be far more vulnerable to military and economic coercion from China. Some might switch allegiance to Beijing, analysts say. Some might seek nuclear weapons to boost their own security."


There are many references to submarines througout Parts One and Two.

We suggest readers use Control + F inserting "Submarine" to find them. 

Petra and Pete