October 18, 2019

South Korean Defense and Attack Strategies Against Japan

On October 18, 2019 Anonymous commented:

Japan has already noticed South Korea’s (SK’s) suspicious intentions [1, 2]. According to a representative SK paper, SK studied, in the 1990s, “the Strategy of Stinging” to hit Tokyo [3].

[1] Masahisa Sato (the Secretary General of the Japanese Diet members caucus of Liberal Democratic Party, and Vice Minister for Foreign Affairs) tweeted (in Japanese) December 25, 2018:

“The basic design of the next 3,000-ton class submarine has been completed in South Korea. Scheduled to be built from late 2019. According to a South Korean announcement, the submarine will be built to respond to threats from all directions and can be equipped with six ballistic missiles with a range of 500km. Where is the main enemy of this submarine? [What is SK’s intent?]”

[2] “South Korea’s epoch-making defense budget of 50 Trillion won [US$42.4 Billion], “North East Asia budget” to check neighboring countries”, SK's JoongAng Ilbo (in S Korean) August 29, 2019 https://news.joins.com/article/23565170

“South Korea's defense budget is expected to exceed 50 trillion won [US$42.4 Billion] for the first time. The South Korean government explained that it will greatly increase its defense spending to prepare for the conversion to wartime warfare. It was confirmed that there was also [an intention to build a military capability] to keep in check neighbouring countries such as Japan and China.”

[3] “South Korean Government Self-Defense Strategy New Version [Against] Pyongyang Bay? Beijing and Tokyo”, SK's JoongAng Ilbo (in S Korean), September 22, 2019, https://news.joins.com/article/23583206

“Another concept of independent defense against neighbouring countries is the Strategy of Stinging. An SK government source, asking for anonymity, said, “At the National Research Institute of the 1990s, we studied how to fight in disputes with neighbouring countries under the [code] name of “Key Research”. [The Strategy of Stinging involved the possibility of stinging the core of neighbours]. In other words, the Strategy is to neutralize the command or major facilities in Beijing or Tokyo.” (Only SK version)


October 17, 2019

Future South Korean Nuclear Submarine Seen As Threat to Japan

On October 17, 2019 Anonymous provided the following useful and timely comment with links.

The South Korean (SK) Navy officially admitted it is making efforts to secure a nuclear submarine [1].

On October 10, 2019 the Chief of Staff of SK Navy officially announced that an SK nuclear propelled submarine is the most convenient way to follow and destroy North Korea (NK) submarines that are capable of firing nuclear tipped submarine launched ballistic missiles (SLBMs). 

The Chief of Staff of SK Navy also stated  that an SK nuclear propelled submarine could be a "useful deterrent" against neighbouring countries. [Pete Comment: By "deterrent" the Chief of Staff of SK Navy is presumably meaning SK missiles with nuclear warheads as a handful of missiles with  conventional warheads would be no deterrent (particularly to nuclear armed NK)]. 

The Chief of Staff of SK Navy explained that an SK nuclear propelled submarine is not restricted by the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) or Safeguards Agreements of the International Atomic Energy Agency (IAEA). 

The Japanese government will interpret “neighboring countries” to mean NK and Japan and that SK Navy considers Japan as a virtual enemy [2]. This is because the SK Navy would never attack heavily nuclear armed China and Russia.

[1] South Korean Navy "Efforts to secure nuclear submarine ... convenient for North SLBM", Radio Free Asia, October 10, 2019 (in Korean - right-click mouse to translate)

[2] “Development of an SSN starting in SK before Japan [builds an SSN]” by Jun Kitamura, October 17, 2019, [Japan's] JBpress, (in Japanese) https://jbpress.ismedia.jp/articles/-/57942?page=4 which displays the SK SLBM range map (below) to hit Japanese territory:

SK Navy submarine attack posture simulation [against Japan] (Map courtesy [Japan's]
-  "SSK" [or SSB?][conventional sub]: SK Navy KSS-III batch-2
    [or Batch II already designed
launch point to fire SLBMs [at Japan] 
-  "SSN" [or SSBN?]: SK Navy launch points to fire SLBMs [at Japan] 
"Red fan is SLBM range"

Pete Comment - The South Korean SLBMs may become a longer range variant of the land based Hyunmoo-2B (range with 500kg warhead 800 km in 2012?) or of the future Hyanmoo-4 (likely to have a range, with 500kg warhead, well over 1,000km).

Anonymous (some Pete comments)

October 14, 2019

3 Submarines by L/D ratios. 2 Subs by I Ratios, eg. for Netherlands. India?

On October 12, 2019 Anonymous provided the following useful comments and calculations which compare: (A) Naval Group, SAAB and TKMS submarines against Length (L) / Diameter (aka Beam) (D) ratios, and (B) SAAB-DAMEN and TKMS submarines against Indiscretion Ratios (IRs). 

(A)  Length (L) / Diameter (aka Beam) (D) ratios

Naval Group, SAAB and TKMS have proven submarines with similar dimension:
-  Scorpene AM-2000 (displacement 1,870 tons (t); length (L) 70m; Diameter (D) 6.2m, L/D = 11.2) 
-  A26 (1,930t, 63m, 6.4m, L/D9.8) and
-  Type 218SG (2,200t, 70m, 6.3m, L/D11.1), respectively. 

To achieve a larger submarine (say for the Netherlands) with a displacement of 3000t (if required?) with a simple hull extension (aka plug) the estimated L/D = 15-18 considerably deviates from the optimal L/D = 7-10 [1]. SAAB and TKMS proposed new submarines with bigger beam (to achieve an optimal L/D) presumably based on the existing (Collins-class) or mature paper designed submarine (Type 216). Unless Naval Group can offer submarine with optimal L/D, a successful bid will be a long shot.

(B) Indiscretion Ratios (IRs)

On the basis of rough estimates [2] the Indiscretion Ratios (IRs):
-  large SAAB-DAMEN A26 (3 x MTU diesels, LIBs, Stirling-AIP) = 3.8/% 
-  large 212CD (2 x MTUs, LIBs, FC-AIP) = 4.2%

So the IR of the SAAB-DAMEN A26 is slightly smaller than the 212CD's thanks to the A26's 3 x MTU diesels. These IRs are far superior to IRs of LAB-submarines (around 12%).

There are two strategies to achieve a low IR by using LIBs:
-  one is a combination of diesels and AIP, and 
-  another is the adoption of high power diesels. 

To achieve 4% of IR without AIP, SAAB-DAMEN needs 5 x MTU diesels [with LIBs] or 2 of the latest KAWASAKI diesels [with LIBs].

[1] “Optimum L/D for Submarine Shape”, by M. Moonesun and others. Indian Journal of Geo-Marine Sciences, vol.45(1), Jan/2016, pp. 38-43 at
(Conclusion is on page 42) The main achievement of this paper is the suggestion of an L/D = 7-10 as the optimal range for cylindrical middle body submarines.

[2] Assumption: AIP is used for 50-days submerged surveillance in a 70-day mission. Power consumed per hour is 0.2MW (c = hotel load 0.15MW + propulsion input 0.05MW). Then, total energy to be consumed for the surveillance is 240MW (e=c*24 hours*50days) consisting of an energy supply from AIP (d = c*24hours*submerge period by AIP (a) = 4.8*a) and that from diesel 
(j = 240MW-d). IR is related to daily energy supply (g = j/50days) from diesel with electrical output (b), namely, IR = 100*g/(24*b).

- SAAB-DAMEN: a=20days, b=3*MTU=3.12MW, d=96MW, j=144MW, g =2.88MW, IR=3.8/% and
212CD: a=28days, b=2*MTU =2.08MW, d=134.4MW, j=105.6W, g=2.11MW, IR=4.2%

Submerged period by AIP, hotel load and propulsion input are estimated in various articles.

Pete Comment - Naturally many other technical, cost and Dutch content variables will be part of the Netherlands' future submarine decision. Also, as Submarine Matters October 11, 2019 article records, Netherlands' domestic political factors and international relations with supplier countries will also influence the selection. India is also considering the selection of 6 Project-75I AIP submarines.  

Mainly Anonymous (Pete some editing, comments)

October 11, 2019

Dutch Navy Document Clarifies Dutch Future Submarine Competition

Anonymous has identified an excellent Dutch article that, to an extent, clarifies the issues of the Walrus Replacement Program (ie. Dutch future submarine competition). The article is centered on a Dutch Navy document.

The article is by Olof van Joolen and Niels Rigter in the Dutch language De Telegraaf,
October 2, 2019 titled “Angling fishing for submarines” at

(Pete has translated it into English, bolding some parts and adding the links)

"THE HAGUE - The four new submarines for the Navy must be of Dutch origin as much as possible. The large trade unions and the employers' organization VNO-NCW advocate this at the [Dutch] House of Representatives and the Cabinet.

They are doing this just before the matter is raised at the central political structures at The Hague [The Hague is the seat of the Dutch Cabinet, the States General, the Supreme Court, and the Council of State.]. From an internal comparison that De Telegraaf was given insight into, the Dutch / Swedish combination Damen / Saab seems to have the “best papers” for the multi-billion euro selection but the French Naval Group is chasing the consortium.

The unions, including FNV, CNV and De Unie, have already put agreements with Damen on paper that the shipbuilder use Dutch personnel, Dutch knowledge and development and production sites on Dutch soil as much as possible. The unions have also made agreements with the yard about internships, flexible staff and the remuneration of freelancers. “The parties will sign the agreements next week.”

This means that those involved anticipate things. With the Swedish Saab, Damen is only one of the four candidates to develop and build the replacement for the Walrus submarines now in use by the Navy.


However, the purchase of the four new submarines is not going smoothly. Ministries involved all want something different. Moreover, there are concerns about the risks of the multibillion euro project.

Pros and cons. An internal candidate comparison document written by the Dutch Navy shows which of four yards (in the race to build the future submarines) has the best characteristics. Saab / Damen scores best for Dutch industry and for maintaining strategic knowledge. The Swedish-Dutch consortium can also show sufficient projects (frigates and submarines) to inspire confidence in the piece that De Telegraaf was given access to. A 'risk management plan' is essential. Not unimportant for a project that costs at least 3.5 billion euros.


The [Dutch Navy's] candidate comparison shows that the role of the Spanish submarine builder Navantia “has been played out.” [eliminated?] The German TKMS is second to last in the ranking. The French Naval Group is chasing Saab / Damen. If the [Dutch] navy were in charge, the choice had already been made. The Netherlands would have Saab design the new submarines, have them built at Damen, with a pendulum of Dutch companies on board. After all, a good injection for Dutch industry and the Netherlands as a knowledge country. Moreover, Dutch defense would remain hooked on the very latest military technology and get exactly the boat it wants.

But the Navy is not in control. And the Ministry of Defense cannot decide independently. The Department of Economic Affairs and Climate is also on board and seems sensitive to the Dutch industrial map that Saab / Damen have drawn. But Finance, Home Affairs, Foreign Affairs and General Affairs are also involved. They want something different. An "initiate" [insider]  summarizes it as follows:

"Broadly speaking, the

Defense organization wants a state-of-the-art submarine quickly,

Department of Economic Affairs and Climate wants a boost for the Dutch defense industry,

Finance wants as cheap as possible,

Home Affairs (with D66 minister Ollongren at the helm) wants TKMS, because it is European, and

Department of Foreign Affairs wants to maintain a good relationship with the French. ”

Prime Minister Rutte would also be sensitive to this.

The decision about which party or parties will continue to the next round therefore becomes more a political than a technical decision. It should have been decided last year. It is now expected in the coming weeks.

The postponement is due to a change in direction of this government, in which the importance of Dutch industry became more prominent, followed by a strongly intensified lobby by two participating parties. The German TKMS promising to place the construction of the Dutch submarines with the naval company in Den Helder and the French teaming up with the Dutch dredger IHC builder.


Since the 1990s, Damen has built all large ships for the Navy, but not yet a submarine. This is a  risk. Moreover, making boats that are completely tailored to the wishes of the Navy is much more expensive. The fact that the defense budget is not rising as fast as expected means that a new submarine built on Dutch soil is far from certain.” ENDS

Pete Comment

So the competition continues to be undecided. The decision timeline is still vague. Being “more a political than a technical decision” (a reality suffered by submarine selectors in many countries) adds to uncertainty. 

If risk is a worry then an enlarged version of a submarine that does not yet exist (eg. the A26, S-80 Plus and Type 212CD) is risky. The Dutch may see a large version of Naval Group's Scorpene as less risky than a small version of the not yet developed conventional Shortfin Barracuda.

Other major issues include do the Dutch require Air Independent Propulsion (AIP) and/or Lithium-ion Batteries (LIBs) or neither?

Next week Pete will describe Naval Group's progress in developing second generation AIP.

Anonymous and Pete

October 8, 2019

SAAB-DAMEN Ahead in Netherlands’ Walrus Replacement Program: But Wait!

In early October 2019 Anonymous kindly supplied further useful comments and links on the Netherlands’ Walrus Replacement Program (competition). Submarine Matters interest in Dutch submarine affairs goes all the way back to 2015 when "Kevin" provided useful insights.

Anonymous continues - Spain’s Navantia (marketing the S-80 Plus submarine) has been definitely excluded from the Walrus Replacement Program, because Navantia continuously committed serious and foolish design errors [1, 2].


In the Walrus Replacement Program the following submarines might be compared:

a large TKMS Type 212CD with such technologies as Fuel Cell AIP = FC-AIP of the Type 212A
a broader beam Type 216-like submarine

-  a large SAAB-DAMEN modified A26, with such technologies as a Stirling engine AIP, in a wider
   Collins-like hull of broader beam [3].

A large Type 212CD can be compared with a large SAAB-DAMEN A26 against criteria (1) - (10) below:

(1) Efficiency: 212CD’s AIP greater than SAAB-DAMEN A26’s
FC (which is an electrochemical system) is superior to the Stirling engine (a heat engine) in efficiency .

(2) Diving depth of AIP: Type 212CD greater than SAAB-DAMEN A26
Metal hydride FC (non-CO2 reforming type) generates water and is not affected by diving depth. The efficiency of the Stirling engine is reduced with an increase in diving depth because of increased exhaust back pressure (max. operation depth = ca.200m). Actual operation of the Stirling seems to be considerably shallower than 200m.

(3) Safety: the SAAB-DAMEN A26 is safer than the Type 212CD
The Stirling engine has greater safety than metal hydride FC [which releases flammable-explosive pure hydrogen].

(4) Availability of Fuel (Hydrogen and diesel): SAAB-DAMEN A26 superior to Type 212CD
This might be a Netherlands’ specific requirement [4, 5]. As the mission of a Walrus-class submarine is sometimes quite long (max. 3 month), reloading of fuel is required in remote areas [eg. the Dutch Caribbean, and Middle East. For Metal hydride FC, availability of hydrogen in remote areas seems to be difficult [6]. In comparison availability of diesel for a Stirling engine is no problem.

(5) Reliability of hull: SAAB-DAMEN A26 superior to Type 212CD
A base model of a Type 216 (which would strongly influence a large Type 212CD if required by the Netherlands) does not exist. Meanwhile a large SAAB-DAMEN A26 would presumably be based on the Collins-class which does exist and with proven hull and performance.

(6) Output of diesel: SAAB-DAMEN A26 superior to Type 212CD
The Type 212CD and a large SAAB-DAMEN A26 would be equiped with two and three MTU diesels respectively. The three MTUs-system of SAAB-DAMEN complements lower performance of Stirling engine.

(7) Job creation and technological contribution in Netherlands: SAAB-DAMEN A26 superior to Type 212CD

(8) Business situation of builder: SAAB-DAMEN A26 superior to Type 212CD
There is a rumor that of the parent company (Thyssen Krupp) will eventually sell TKMS.

(9) Product quality of builder: SAAB-DAMEN A26 superior to Type 212CD
TKMS was heavily criticized on bad quality – see [7, 8 below].

(10) Appropriateness for mission in hot and remoted area: SAAB-DAMEN A26 superior to Type 212CD
The inappropriateness of the TKMS 212A in hot and remote sea areas has been reported in the Netherlands [9 below]. These issues should be resolved in the tender of WRES. In the case of SAAB-DAME, experience of Collins-class in hot and remoted area is expected to be used.


On the basis of criteria (1) - (10) a large SAAB-DAMEN modified A26 appears to be superior to a large Type 212CD for the Walrus Replacement Program (competition).


[1] “£2 billion Spanish navy submarine will sink to bottom of sea”, Fiona Govan, May/22/2013, The Telegraph, https://www.telegraph.co.uk/news/worldnews/europe/spain/10073951/2-billion-Spanish-navy-submarine-will-sink-to-bottom-of-sea.html
“A new submarine commissioned by the Spanish navy at a cost of 2.2 billion euros (£1.9billion) has been discovered to contain a serious design flaw – it is too heavy and will sink like a stone.”

[2] “Spain's new submarine 'too big for its dock'”, BBC, July/18/2018 https://www.bbc.com/news/world-europe-44871788
“The S-80 boat was redesigned at great expense after an earlier mistake meant it had problems floating, and it was lengthened to correct the issue.”

[3] The beams of the Type 212A (6.8m), Type 214 (6.3m) and A26 (6.4m) are considerably smaller than that of the Walrus-class (8.4m). The extension of beam means new design of hull, and it is very expensive and time-consuming work. The most effective extension method is diversion of existing hull design with bigger beam such as Type 216 (8.1m) and Collins (7.8m) and application of existing information and data such as strength calculation and hydrodynamics. The beam of the Type 216 and Collins is smaller than Walrus-class, capacity of the former two is bigger than that of the later where tear-drop shape and double hull structure are applied.

If displacement of the Walrus Replacement-new Netherlands submarine is ca. 3,000 tons, the length of the required larger Type 212CD and SAAB-DAME A26 will be ca. 65m, where ratio of length/beam is ca.8 closed to its ideal value of 7.

The availability and cost of fuel must be considered for the long-range, long-term submarine missions to the Dutch Caribbean Sea - which contains the overseas territories of Aruba, Curaçao, and Sint/Saint Maarten.

[5] “Marineschepen.nl” (Walrus class submarines : Operational deployment), Jaime KarremannFeb/16/2019marineschepen.nl, https://marineschepen.nl/schepen/walrus.html 
[Long range] Deployment of Walrus-class submarines: the Persian Gulf, the waters around the Arabian Peninsula and the Indian Ocean, the Caribbean (max. 3months), the coast of East Africa, etc.

As maximum mission period of Japan's Soryu-class submarines is 70 days depending on food stock (the Collins-class is also the same), reloading of food and fuel and rest of crews are needed for a 3 month mission of a Netherlands’ submarine.

[6] Die Brennstoffzelle auf U 212 A, page22/24, 23/24, Sept/23/2008
In Europe, Gaseous or liquid hydrogen is carried by tank truck and is stored in cryogenic tanks in Europe. But, in remote areas, affordability of (gaseous or liquid) hydrogen is difficult. Liquid oxygen (oxidizer) is needed for both FC and Stirling engine, but, its affordability is not so great or difficult.

[7]Das Boot”, Jan/15/2015, SPIEGEL ONLINEhttps://www.spiegel.de/spiegel/print/d-131355085.html
“The new, expensive high-tech submarines (212A class) should be the pride of the [German] Navy. But internal documents prove how breakdowns and deficiencies delay their use by years.”
Here, a range of problems regarding the Type 212A have been reported. “The engineer is annoyed above all that the manufacturer of the submarines, ThyssenKrupp Marine Systems in Kiel, apparently has learned nothing from the mistakes of the past.”

[8] “MKS 180 program : the master stroke of German Naval Yards”, Defence Chronicles, Aug/16/2018, https://www.defencechronicles.eu/mks180-program-the-master-stroke-of-german-naval-yards/
“Technical failures and bad management have inflated the costs and imposed significant delays to both programs, leading the German procurement authorities to oust them from the MKS 180 race.”

[9] “Marineschepen.nl” (Somali waters too warm and too far for German submarines), Jaime Karremann, Mar/14/2016, marineschepen.nl, see https://marineschepen.nl/nieuws/Duitse-onderzeeboot-niet-naar-Somalie-140316.html
“Last year, the German navy announced that a German submarine would go to Somalia to collect intelligence about pirates. After months of research, Germany has canceled the mission: the water around the Horn of Africa is too hot and the distance is too long for German submarines.

Pete Comment - A third alternative, Naval Group, appears to be becoming a more serious contender in the Walrus Replacement Program (competition) - see further details later this week.

Anonymous (with some editing by Pete)