January 30, 2015

Indian Possible Interest in Buying-Building Japan's Soryu Submarine - Australia

Two Prime Ministers - Japan's Abe and India's Modi. Are their countries close enough for a Soryu deal?

The Indian press reported on January 29, 2015 that India, under submarine purchasing-building Project-75I (I for India), may wish to select six Japanese Soryu submarines for building in India. The Rs 50,000 crore project price converts to $US8,133,990,000 that is $US8.13 Billion (where one crore is 10,000,000 Indian Rupees and one Rupee is worth 0.016 US Dollars).

See reference on Submarine Matters to:
-  the slow pace of the Project-75I selection way back to 2008 and 2011
-  then an article of August 2014 (which also mentions the already building 6 Scorpene "Project-75" no "I")
-  see also the 2014 reference to the DRDO fuel cell which has complicated Project-75

If a legitimate tender process is held other contenders to sell a large conventional submarine are:
-  Germany (TKMS-HDW)
-  Russia (Rosoboronexport)
-  Spain (Navantia)
-  Sweden (Saab-Kockums), and 
-  France (DCNS). 


Several problems already seem evident in the possibility of Japan selling Soryus to India:

1. India's "build in India" intention may clash with Japan's (to date) insistence that any Soryus it markets should be built in Japan. 

There may be a solution that may allay many of Japan's concerns. If Japan is interested it can contact me by email - see email on my profile...

2.  Japan would be mindful of India's closeness to Japan's strategic opponent, Russia. Japan is very sensitive to the security of its submarine technology secrets. Therefore Japan would not want the secrets of any Soryu that is sold to India to be passed on to one of Japan's opponents. India has been close to Russia on a defence sales, weapons' development and on secondment of personnel, levels for decades. India and Russia are particularly close on submarine high technology matters - including INS Chakra, the Akula II SSN that Russia has long leased to India. 

3.  India may perhaps have a problematic reputation as a weapons system buyer from Western firms. France is unfortunate enough to be involved in both the major examples. 

a. The first example is in-building Project-75 (no I) where France (DCNS) has been assisting India to build 6 Scorpenes for the last decade (see Project 75 and third paragraph of this Indian article ). India has expressed displeasure with alleged French caused delays. Over the years India has increasingly wanted AIP in those Scorpenes - India sees AIP as important - in part to surpass the three AIP equipped DCNS Agosta 90Bs submarines operated by Pakistan. But India may not wish to pay the higher price adjustment that DCNS would want to charge (AIP being an expensive upgrade). India has countered with a project by DRDO to develop a fuel cell AIPIndia may also be using the usual strategy of great powers (sellers and buyers) - which is delay for political and commercial leverage. 

b. Secondly, under the Medium Multi-Role Combat Aircraft (MMRCA) competition - on 31 January 2012 it was announced that Dassault Rafale won that competition. The MMRCA competition may be worth around US$30 Billion. However on 10 January 2015, India hinted it would not sign the Rafale deal with Dassault but instead perhaps buy more Su-30MKIs or Su-35s from Russia. India may also be attempting to leverage a better result from Russia on the joint India-Russia PAK- FA stealth fighter-bomber project - also known as the T-50. 

4.  If India insists on AIP this may cause problems for Japan. In Japan's first 5 Soryus Japan included Stirling engine AIP from Sweden. It is unlikely that Japan would receive Swedish permission to sell Soryus with Stirling AIP to India. Sweden, after all, would prefer to sell its own Saab-Kockums  submarines, with Stirling technology, to India. If Japan accepted an offer from India-DRDO to build an indigenous fuel cell AIP (see above) this may be a problem or opportunity because Japan may be in a strong technological position to jointly or unilaterally develop an AIP.  

Broader Implications - Australia and Canada

If there is a prospect of "build Soryus in India" - even whether or not it happens - this may have implications for any Japanese Soryu sale to Australia. Perhaps "build Soryus in part or whole in Australia" might be more possible?

If India is serious about buying 6 very large conventional submarines - built in India - with AIP - then Germany's HDW 216 and France's SMX Ocean may both be stronger contenders than Japan's (build in Japan - maybe no AIP) Soryu. This may increase the production runs and drive down development costs for the 216 and/or SMX making them more attractive to Australia. Canada has also been grouped with India and Australia as a country with a relatively large budget in need of large, long range, replacement submarines.

Please connect with India's Rising Nuclear and Conventional Submarine Force, May 21, 2015 http://gentleseas.blogspot.com.au/2015/05/indias-rising-nuclear-and-conventional.html .


January 29, 2015

Australian Prime Minister's Decline Weakening "Buy Soryu"

Are the sinking fortunes of Prime Minister Abbott also sinking the Soryu?

The last week has presented a further example of Australian Prime Minister Tony Abbott's  lamentable political  judgement. Abbott is weakening his influence in his own Liberal Party and in Australia generally.

Regarding Australia's biggest future defence purchase - Abbott has frustrated many in his Party by going beyond the normal prime ministerial role. This is in terms of Abbott going over the heads of his former Defence Minister and perhaps his current Defence Minister Kevin Andrews in unilaterally(?) selecting a specific high cost weapons system - the Soryu submarine. If Abbott is doing this to please the US, and/or to build a special relationship with like-minded conservative politician Abe, then Abbott might want to reconsider. A proper tender for the future submarine is needed.

The future submarine (Soryu or not) may be with Australia for 45 years (selection, production, then in-service) perhaps long after Abbott and Abe are forgotten.

Abbott's support for the Soryu has always been opposed by most in his own Party, by many in the Australian Navy and probably most defence civilians in Canberra and Adelaide. With Abbott's decline the Soryu's chances of selection has declined. If or when Abbott is removed by his Party from the Prime Ministerial position it is not clear whether Abbott's policy of "buy Soryu and build in Japan" will be maintained.

Japan may not always be an ally but even a problem for Australia - as has happened before. At a minimum Japan may want Australia to join Japan in armed confrontation against China. Abe and new Defence Minister Nakatani are a rightwing departure from Japan's usual pacifist defence policies. They may change the defence complexion of Japan - not necessarily in line with Australian interests.

Abbott may have a conservative ally and loyal supporter in new Defence Minister Kevin Andrews. However Kevin Andrews is too new to the Defence portfolio, with no track record on defence issues, to have his own base of power to support a Soryu purchase - yet. Like earlier Defence Minister Dr Brendan Nelson Andrews may make a good Defence Minister in the near future.

There is powerful support in Abbott's own Party, the Navy and the Defence Department for the build of part or all of the future submarine in Australia. Germany's TKMS, France's DCNS and Sweden's Saab have made strong bids that support "Build in Australia." This means that if Abbott goes these other bids may win. Japan may need to be flexible enough to counter with a genuine "part or fully build in Australia".

No commentators or politicians are recognising the early January 2015 "Manufacture Soryu submarine steel in Australia" offer as genuine "Build in Australia". This is partly because this Australian steel will just be thrown on Japan's existing submarine steel stockpile. No-one expects Japan to be dependent on Australia for strategically vital submarine steel.


Details on Prime Minister Abbott's latest political mistake, particularly in not consulting his Party, are:

MELBOURNE Australia - "Australian Prime Minister Tony Abbott said on Wednesday he stood by his controversial decision to award Britain's Prince Philip a knighthood and was taking the firestorm of criticism "on the chin".  Several ministers [also called "frontbenchers"] have walked away from Mr Abbott's appointment of the nonagenarian Duke of Edinburgh to the ranks of the Order of Australia, MPs on all sides have mocked the move and the media condemned it severely."

The Australian, a major newspaper from Rupert Murdoch's powerful media empire, ran a highly critical editorial asking: "Tony Abbott is in office but is he prime minister?" http://www.theaustralian.com.au/opinion/editorials/tony-abbott-is-in-office-but-is-he-prime-minister/story-e6frg71x-1227198890579 
"The decision to turn a distant duke into a knight Down Under suggests a prime minister who is tone deaf or, worse, complacent in his power to push through a personal preference indifferent to the fact that it is bound to enrage and bewilder many," it said."


January 25, 2015

Japanese Concerns Over Any Soryu Sale to Australia

Prime Ministers Abbott and Abe, on April 7, 2014, when they concluded a framework agreement for co-operation on defence equipment and technology (including submarine hydrodynamics). This is/was a preliminary to any Soryu sale. Abbott's political position is now threatened. 

As Prime Minister Abbott - the main Australian advocate for a Soryu deal  steadily weakens politically it is valuable to consider possible Japanese concerns and misgivings over a Soryu sale.

Several days ago an Anonymous commenter said [retired Admiral]"Kobayashi is not arrogant, he just does not want to sell sub tech, that’s all. Australian thinks that Japan wants to sell her subs like Germany, Sweden or France. But this idea is perfectly wrong and huge misunderstanding, Japan does not want at all. Soryu’s secret is more important and valuable than money which Australia will pay Japan." 

Enlarging on possible Japanese concerns yields the following possibilities.

Unlike other western countries involved in Australia's submarine selection - Japan is the only country actually in danger of conflict - with North Korea and to a lesser extent with Russia and China. Other contenders - Germany, France and Sweden - are not at risk. For these latter three countries the submarine selection is only a commercial-trade matter - while for Japan it is most importantly a strategic alliance, national security matter.

A sale of Soryus to Australia may weaken Japan's national security:

Selling to Australia would involve a major diversion of Japanese industrial and submarine corps resources to plan, train and generally liase with Australian industry and Australian submariners. Japan's limited resources might be better focussed monitoring or more active measures against Japan's potential enemies.

Sales to Australia might disrupt Kawasaki Heavy Industries (KHI) and Mitsubishi Heavy Industries (MHI) submarine production lines to supply the Japanese submarine corps. This particularly in view of Japan's goal of expanding its submarine corps from the current 16 operational submarine to the goal of 22 submarines. More specifically there may be strategic pressure for a Soryu earmarked (by contract) for Australia on a production line to be diverted to thJapan Maritime Self-Defense Force (JMSDF) instead. Such a diversion might raise political and contractual difficulties for Japan.

The prospect of sales to Australia may encourage the Soryu's submarine builders (MHI and KHI) to modify the Soryus to a standard configuration that does not suit JMSDF requirements. For example it is possible that two reasons for Japan's decision to delete Stirling air independent propulsion (AIP)  from the future batch of Soryus were:
- Australia's assessment, since the 1980s, that AIP is problematic, involving negative trade-offs, that  do not meet Australia's needs, and
- for legal property right reasons Japan could not sell Swedish Stirling engine AIP technology to third countries, including Australia.

It is also possible the future batch of Soryu will have much longer range, to suit Australia's operational requirements but this longer range might not be ideal for the JMSDF's needs.

Due to China's trade value to Australia Japan cannot rely on Australia to support Japan in any confrontation or outright conflict with China (eg. arising from East China or South China Sea matters). Australains see the islands in the East China and South China Seas as more to do with current opportunistic economic claims than national historical claims. This means that in any conflict in those seas Australia may support the claims of its major trade partner - which is China.

Australia's security laws and rules may be detrimental to Japan's security overall. Part of the weakness would stem from Chinese government and corporate  influence over Australia. For example Australia's China situation may result in Australian steel-making companies inadvertently sharing newly acquired Japanese steel secrets with Chinese steelmaking business partners.

Australia's laws overall make racial discrimination illegal in employment - particularly for government jobs, including the submarine corps. A main area of Japanese concern might be Australian tolerance of former Chinese citizens, or ethnic Chinese generally, being inducted as Australian submariners or into broader Australian government or submarine-shipbuilding industry positions. China has a reputation for pressuring ethnic Chinese in the West - even if they have only distant cousins or elderly grandparents still living in China. The Chinese government can deny Chinese citizens careers, lose jobs, lose pensions or worse if their Australia based relatives are not cooperative. Australia cannot match Japan's ability to control the ethnic security of submarine crews or such security in the broader submarine industry.

January 21, 2015

Comments on What Appears to be a Soryu Sale Press Relaease

The Soryu lobby (Japan of course but to an extent the US) issued what amounts to a Soryu Press Release (see below) on January 20, 2015. This was possibly to influence any statements Australian Defence Minister Kevin Andrews was expected to make during his visit to the Australian Submarine Corporations (ASC) submarine facility in Adelaide on January 22, 2015. As it turns out Andrews said little memorable other than the Australian Government had made no submarine selection decision.


After some positive feedback (with pertinent information) from Japanese commenters I'm toning down the title and some of my comments in the post. The "Soryu Press Release" is a Japan Times article of January 20, 2015. The article/Press Release:

- would have been mostly written by and cleared by the Japan Ministry of Defence.
- there is the exaggerated implication that Australia is privileged to be allowed to receive such a Japanese technical achievement.
-  but nevertheless Japan may not carry out the standard industrial task of revealing to Australia key technical secrets. This withholding of secrets may include those behind the Soryu's  potentially dangerous Lithium-ion battery (LIB) see "Japan...has yet to decide which secrets to share".
- that the US is in favour of the Soryu export to Australia for the US's own strategic and financial reasons
- makes the standard claim that is Australia is happy to work in strategic alliance with Japan and the US over Japan's interest in contested islands in the East China and South China Seas. Australia has been very cautious in not being drawn into Japan-China cofrontations in those seas
- basically Japan's Soryu pitch is that Australia is strategically obligated to buy the Soryu..

There is some recognition by Japanese commentators that Australia will incur major economic costs by sacrificing much of its ship-submarine building industry. However these  commentators under-rate the opposition and rift in Prime Minister Abbott's own governing Party with increasing feeling against submarines being built in Japan. Instead there is increasing support across the` political spectrum and within Australia's Navy favouring construction of the submarines in Australia.

The risks for Australia of being Japan's first major defence customer are ignored.

An incentive for Japan is, of course, is Australia's money to offset Soryu 2 (Lithium battery) development costs.

 The article/pitch/Press Release is below - with string  http://www.japantimes.co.jp/news/2015/01/18/national/stealth-tech-no-given-in-japanese-sub-deal/#.VL3UDUeUen8 :

"Stealth tech no given in Japanese sub deal


Retired Vice Admiral Masao Kobayashi commanded Japan’s submarine fleet from 2007 to 2009. In a recent interview in Tokyo with The Japan Times, when asked to explain one of the country’s most tightly guarded military secrets, he seemed reflective.
Kobayashi pointed to the ceiling lights in the quiet interview room and said: “Take those fluorescent lights, for example. Any fluorescent light generates sound.”
Other than our voices, there were no other sounds in the room.
“Fluorescent lights generate extremely small vibrations. We take anti-vibration measures for every single light in a submarine,” he said.
Japan’s engineers have painstakingly worked to minimize the vibrations given off by the multitude of components in submarines to prevent even those undetectable by the human ear from being picked up by the super-sensitive sonars of enemy subs and sonobuoys from anti-submarine aircraft, Kobayashi said.
Noisy components include fans, pumps, motors and fluorescent lights. Some are carefully muted with vibration-damping rubber, he said.
“The quiet submarines we have today are the result of numerous long, patient efforts,” Kobayashi said.
The Maritime Self-Defense Force’s submarines are not nuclear-powered but have a reputation for being ultra-quiet.
Now Australia, seeking to build a new fleet of large, long-range submarines, seems keen on acquiring Japan’s latest Soryu-class subs, or at least their technology.
If the deal goes through, the top-secret submarines will become the first major pieces of military hardware Japan has authorized for export since the administration of Prime Minister Shinzo Abe lifted the decades-long blanket ban on arms sales last year.
Vice Adm. Robert Thomas, commander of the U.S. Navy’s 7th Fleet, reportedly said Oct. 24 in Tokyo that then-Australian Defense Minister David Johnston was very interested in Japan’s Soryu-class subs.
“I talked to him about it four years ago and I said: ‘You want to find the finest diesel-electric submarine made on the planet — it’s made at Kobe works in Japan,’ Thomas was quoted as saying by Bloomberg News.
The U.S., which has close but separate security pacts with Japan and Australia, probably wants Australia to buy Japanese submarines because it would greatly strengthen their strategic military ties, Kobayashi said.
Deeper Japan-Australia military cooperation would help ease the heavy burden on the U.S. fleet, which is busy decommissioning many of the nuclear-powered attack submarines it built during the Cold War, he said.
“The U.S. rapidly built many Los Angeles-class nuclear submarines during the Cold War. Many of them are being decommissioned now,” Kobayashi said.
“I think the U.S. wants to create a strategic triangle of Japan, Australia and the United States. That’s probably a factor behind” the apparent U.S. nod to Australia’s proposal to Japan, he added.
Japanese defense officials are thought to be pleased for the same reason Washington is. They want to deepen strategic military ties with Australia.
“Australia would make a good partner for cooperation. There are no major diplomatic problems between the two countries other than whaling,” a senior Defense Ministry official said on condition anonymity. Australia opposes Japan’s annual whaling expeditions.
Japan has just started receiving the submarine specifications sought by Australia but has yet to decide which secrets to share, two senior defense officials said.
Japan soon plans to use lithium-ion batteries to drive the motors in its latest Soryu sub, making them even quieter. Australia is believed to be interested in this advance, the officials said.
But advanced lithium-ion batteries are one of Japan’s top military secrets, one warned.
“(Exporting) them would be a rather sensitive issue. We’d need to study if it’s really appropriate for an outside party (to have that technology),” the Defense Ministry official said.
In Australia meanwhile, opposition lawmakers and trade unions are strongly opposed to procuring Japanese submarines because it could considerably undermine the domestic defense industry and reduce jobs in South Australia.
Joint development might be an option, the two Japanese officials said, noting that nothing concrete has been officially proposed.
Teruhiko Fukushima, a professor at the National Defense Academy in Yokosuka, Kanagawa Prefecture, who is an expert on Australia, said Prime Minister Tony Abbott seems eager to procure the subs to bolster Canberra’s military ties with Japan and the United States.
“Abbott should be considering a Japan-U.S.-Australian alliance as a kind of insurance” against the recent rise of China’s powerful military, Fukushima said.
“The introduction of Soryu-class submarines would be a plus to strengthen that alliance,” he added.
“If the Abbott administration survives the next election and wins a second term, there will be a greater chance that Soryu-class submarines will be introduced in Australia,” he said.
Last June, Australia and Japan conducted “two-plus-two” talks between their foreign and defense ministers.
In the joint statement that followed, Australia expressed “strong opposition to the use of force or coercion to unilaterally alter the status quo in the East China Sea and the South China Sea,” an apparent warning to China to not aggressively press its territorial claims in those areas, which include the Japan-controlled Senkaku Islands, which China and Taiwan also claim. China calls the uninhabited islets Diaoyu and Taiwan calls them Tiaoyutai.
Fukushima also said that on Nov. 26, 2013, only three days after Beijing declared the establishment of an air defense identification zone over the East China Sea that included the Senkakus, the Abbott administration summoned the Chinese ambassador in Canberra to express its concerns after the ADIZ drew strong protests from Tokyo and Washington.
“There is no doubt Abbott puts great emphasis on the relationship shared by Japan, the U.S. and Australia,” Fukushima said.
But he also noted that China is Australia’s No. 1 trade partner and that the public would never approve of political actions that could seriously damage those economic ties.
“The best way for Abbott is to strengthen the Japan-U.S.-Australian relationship while maintaining good economic ties with China at the same time. Australia would never turn its back on the Chinese market,” he said." ENDS


January 20, 2015

Soryu Submarine Steel Details - Japan Offer to Australia

A highly automated welding setup for a submarine's pressure hull. In this case a TKMS Type 214 - probably using HY-100 steel.

For Comments of the Arrium issue see the April 8 2016 Submarine Matters article 
Arrium - Pyne's Submarine Steel Claims Don't Stack Up.

Please connect this Submarine Matters post with subsequent post Submarine Steel Strength, China and Japan, April 8, 2015.

It seemed on January 5, 2015 Japanese government and industry tried to strengthen the Soryu (build in Japan) campaign by taking the extra-ordinary step of publicising what was before a confidential negotiating point - that is Japan would assist Australian steel makers in making the steel for any Australian Soryus that are built in Japan. This may mean 10,000 tons to 20,000 tons of special submarine steel made in Australia.

Japan's Naval Steel (NS) Proof Stress Measure

A slight aside - European submarine makers may use an "EN" measure. I am advised by an Anonymous commenter that TKMS-HDW 214 hull is made of "EN" or "WL" 1.3964 (correspond to HY-80) non-magnetic steel. "EN" may mean European Naval while "WL" in German means "Werkstoff Leistungsblatt" (Material Performance Sheet of VG Standard) - see http://www.gl-group.com/infoServices/rules/pdfs/gl_ii-1-6_e.pdf  The US uses a High Yield (HY) unit of measure. Shows how confusing and complex steel measures are! On topic - the Japanese Ministry of Defence uses a "Naval Steel (NS) measure for steel proof stress.

An excellent Japanese document http://www3.ocn.ne.jp/~y.hirama/yh_e_papers_sub_f.html  
"History of the Japanese Submarine (After WWII)" indicates the Japanese submarine steel used for the Japanese Oyashio submarine class that preceded the Soryu class. Perhaps the Soryus use the same steel as the Oyashios. The Japanese Ministry of Defence designation for the Oyashio-Soryu(?) steel is  "NS80" and also NS110. NS80 means a proof stress of 80kgf/mm2 (indicated in Japanese language document http://www.mod.go.jp/trdi/data/pdf/G/G3111C.pdf , page 4, table 4.2.1 left column, with "耐力" meaning "proof stress") NS80 converts to 113,760 lbf/in2 or HY-114. 

If also used in the Oyashios and Soryus NS110 means 110kgf/mm2 proof stress converting to 156,414 lbf/in2 or HY-156.

How this "Combination" of steels are configured is unknown. It may (?) mean:

- each hull of a double hull uses NS80 and/or NS110

- different parts along the the hull use those different grades, or

- perhaps there is a "sandwich" of the two grades.

Language and conceptual difficulties seem considerable with Australian (DSTO or Bisalloy?)  metallurgists perhaps having to frequently make NS to HY conversions using http://www.endmemo.com/sconvert/kgf_mm2ksi.php ?

In terms of depth HY-156 for the Soryu may indicate an operating depth of just over 600 metres (2,000 feet) with a "crush depth" much deeper than that.

On Materials (“HY-80” and “HY-100”, "maraging" and "composites) see BACKGROUND below.

Submarine Steel in Australia

In contrast to Oyashio-Soryu "NS" Steel the Collins class “hull is constructed from a high-tensile micro-alloy steel, developed by Swedish steel manufacturer SSAB, and improved by BHP of Australia, which was lighter and easier to weld than the HY-80 or HY-100 nickel-alloy steel used in contemporary submarine construction projects, while providing better results in explosion bulge testing" [see Yule & Woolner, The Collins Class Submarine Story, pp. 165–174].

So Japan’s (and perhaps Australia’s) future Soryus (the yet to be launched "Soryu 2s") use a steel  combination apparently beyond the capabilities of HY-80 or HY-100 used in the Collins

It is likely that an Australian steel maker will only contribute a portion of the steel tonnage to a pre-existing stockpile in Japan of submarine grade steel. It is highly unlikely that Japan would rely on Australia to be the sole/only source of submarine grade steel for the Soryu. Unsurprisingly Japan values its national autonomy in materials for Japanese developed weapons like the Soryu.

Australian companies approached by Japan may include BHP-Billiton and BlueScope Steel. However the main company Japan approaches is likely to be current naval steelmaker Bisalloy Steels Pty Ltd based in Port Kembla-Wollongong, New South Wales, Australia. 

In the 1980s-1990s Bisalloy supplied 8,000 tonnes of hardened steel for the Collins submarine program with research and development involvement of BHP and the Defence Science and Technology Organisation (DSTO).

Bisalloy Steels Pty Ltd (company website) has connections to Indonesia (PT Bima Bisalloy), Thailand (Bisalloy Thailand) and from July 2011 investment in the Chinese CJV - Bisalloy Jigang (Shandong) Steel Plate Co. Ltd. It would be crucial that Japanese-Australian submarine steel technology does not find its way to foreign affiliates - particularly China.

The DSTO connection is interesting because in July 2014 it was announced that Australia and Japan had agreed to jointly carry out submarine related defence research under an Agreement Between the Government of Australia and the Government of Japan Concerning the Transfer of Defence Equipment and Technology (text of the Agreement as provided by the Japanese Ministry of Foreign Affairs (MOFA)).

As well as the publically stated Marine Hydrodynamics Project this Agreement may involve submarine steel and the DSTO Maritime Division. See DSTO Maritime Division Naval Architecture Project: “Structural materials and fabrication systems - Our Structural Materials and Fabrication Systems group encompasses the performance and assessment of structural materials and fabrication methodologies that may be used in naval structures or critical components within a naval platform. This includes metallurgical assessments and material assessment technologies for both initial selection as well as ensuring through life performance for fatigue.”


WHAT DO “HY-80”, “HY-100”, "Maraging" and Composite Use mean?

The English speaking world is more accustomed to talking about HY units of measure. I originally was going to limited this section to HY (high yield steel) issues - the "Harish" (on maraging) and Anonomous (on Composites) asked timely questions in Comments.

HY-80 and HY-100

"A submarine's hull is normally constructed of steel, or exceptionally of titanium. Special High Yield [HY] steel alloys have been developed to increase the diving depth of submarines, although the improved depth performance of these alloys imposes a price of increased fabrication challenges. These special steels are denominated by their yield stress in thousands of pounds per square inch -- thus HY-80 steel has a yield stress of 80,000 pounds per square inch [called 80 kpsi or more usually 80 ksi] [corresponding to a depth of 1,800 feet], HY-100 a a yield stress of 100,000 pounds per square inch [100 ksi][corresponding to a depth of 2,250 feet], and so on.

During World War II, American fleet submarines normally operated at a depth of 200 feet, though in emergencies they would dive to a depth of 400 feet.

Post-War American submarines, both conventional and nuclear, had improved designs and were constructed of improved materials [the equivalent of "HY-42"]. These boats had normal operating depths of some 700 feet, and a crush depth of 1100 feet.

The Thresher, the first American submarine constructed of HY-80 steel, reportedly had a normal operating depth of 1,300 feet, roughly two-thirds the crush depth limit imposed by the HY-80 steel.

The Seawolf, the first American submarine constructed of HY-100 steel, is officially claimed by the Navy to have a normal operating depth of "greater than 800 feet," and estimated here as 1,300 feet (400 metres). If there is a linear increase then the possible HY-156 for the Soryu may indicate an operating depth of just over 600 metres that is 2,000 feet.

The Soviet Alfa submarines, constructed of titanium, reportedly had an operating depth of nearly 4,000 feet.” 

An interesting February 2008 discussion of the tradeoffs of HY and other materials is here: http://www.defencetalk.com/forums/navy-maritime/steel-alloy-modern-cold-war-subs-7346/ : "I am wondering why in the newest American Seawolf Subs only HY-100 steel (Yield of 100,000 psi) is used, while there were rescue Subs in the 1960s (!) that already had HY-140 steel. Los-Angeles-Subs only have HY-80 steel alloys, what technichal reason is there to use not steel with higher yield?..."


See http://www.keytometals.com/page.aspx?ID=CheckArticle&site=kts&NM=99 . This paper is highly complex. Here is a conversion website for 1,000 pounds per square inch (ksi) and Mega Pascals (Mpa) http://www.convertunits.com/from/ksi/to/Mpa
Under sub-hearding "Medium-Alloy Hardenable Steels"
"There is another type of steel in this general class which is a medium-alloy quenched and tempered steel known as high-yield or HY 130/150. This type of steel is used for submarines, aerospace applications, and pressure vessels, and is normally available as plate. This steel has good notch toughness properties at 0°C and below. These types of steels have much lower carbon than the grades mentioned previously."
Under sub-heading "High-Nickel Maraging Steels" 
"This type of steel has relatively high nickel, and low carbon content. It obtains its high strength from a special heat treatment called maraging. These steels possess an extraordinary combination of ultra-high-strength and fracture toughness and at the same time are formable, weldable, and easy to heat treat. There are three basic types: the steels with 18% nickel, 20% nickel, and 25% nickel. These steels are available in sheet, forging billets, bars, strip, and plate. Some are available as tubing."

Pete's Comment - It seems HY steel (alloy) has toughness but is flexible enough to frequently experience the contractions and expansions of a submarine operating under different pressures-depths. The maraging process meanwhile provides very hard steel (alloy) but that steel is brittle. That steel is not flexible enough for multi-depth expansion and contraction. Maraging steel is particularly useful for tolerating rapid heat changes, making it useful in a submarine's engine but not for a submarine's hull.

Composite Use in Submarines

It seems that in parts of submarine exteriors, and I imagine even more so inside the sub, composities are increasingly used, to save weight and for other benefits. The pressure hulls may remain mainly HY steel or titanium (in some Russian subs?). Areas that heat up greatly may also remain steel.

A statement that probably applies more widely to other submarine makers and nuclear subs is  https://www.thyssenkrupp-marinesystems.com/en/composite-materials.html:

"Constant evolution of [TKMS-HDW subs] allowed for the intensified application of composites. Today for both HDW Class 212A and HDW Class 214 designs beside the traditional Glass-fibre Reinforced Plastics (GRP) also Carbon-Fibre Reinforced Plastics (CFRP) are used. These are used in particular when it comes to the design of large three-dimensional shapes or when outstanding transparency is required, e.g. to cover specific sonar windows."

Pete's Comment - This composite use over sonars may be to avoid steel obscuring too much of the sonar signal spectrum-spread. Also sonars are usually/always? outside the pressure hull - so steel to handle pressure is not required.


January 17, 2015

Updated History and Photos of Japanese Submarines After WWII

The steady evolution of Japan's submarines. See all of the submarines by class below.
(Graph is courtesy of Australia's news-com-au)

The following is based the excellent Japanese document "History of the Japanese Submarine (After WWII)". It used to be at http://www3.ocn.ne.jp/~y.hirama/yh_e_papers_sub_f.html but it seems a dead link "404 not found" now. The document seems to precede introduction of the first Soryu-class submarine that entered Japanese Navy service in 2009.

The document pointed to no author. However I am advised by an Anonymous commenter that the original author of this document is Dr Yoichi Harama, Former Professor of the National Defense Academy of Japan.  

As the original document only went to 2006 I am steadily updating it for the period 2007 through to January 2015I'm also improving some of the grammar. 

Grateful for any suggestions - particularly about the current and future Soryus


History of the Japanese Submarine (After WWII)

Model of Japan's latest submarine class - the Soryu

Defense Plan and Submarines 

Japan had constructed 242 submarines in the Imperial navy era (1869 - 1945), and operated 3530 ton (6560 ton  submerged) I-400 submarine carry three floatplanes during the World War II. However, 58 submarines that remained with the defeat in 1945 were taken over by the Allies Forces and have been dismantled or sunk in the Pacific Ocean.

      By outbreak of the Korean War in June 1950, the National Police Reserve(Later Ground Self-Defense Force) was born in August. While, in April 1952 the Maritime Security Force was organized in the Maritime Safety Agency, and in August the Maritime Self-Defense Force(Hereafter JMSDF) was reformed from the Maritime Security Force and independent from the Maritime Safety Agency.

      During the cold war era, the mission of the JMSDF was aimed the command of the sea of the west Pacific in cooperation with the U.S. navy, against Soviet navy as one of the west side navy, influenced by the confrontation between the east and west. But after surrender the Pacific War, as Japan was enforced by the Allied Occupation Forces to accept the constitution, which declared renunciation of war, as a sovereign right of the nation and the threat or use of force as means of settling international disputes. By this historical background, and strong anti-military feeling among the peoples, the National Defense Council draw up the Basic Policy for National Defense and it was approved by the Cabinet in May 1957. This policy declared Japan has been making efforts on its own initiative to build a modest defense capability under the Constitution in accordance with the fundamental principals of maintaining an exclusively by defense-oriented policy of not becoming a military power that might pose a threat to other courtiers. Though the Maritime Self-Defense Force esteemed to strengthen operational capability of anti-submarine and mine sweeping operation as allies that the U.S. navy is lacking in the northeast Asia area.

        By this defense policy, the main mission of the JMSDF submarine was surveillance and interception of Soviet combatants in major straits. In order to ensure the safety of Japan’s maritime transportation, the JMSDF needs to maintain the posture capable of deploying two submarines each in the three straits of Soya, Tsugaru and Tsushima, where necessary. In order to maintain such capability, it was necessary to possess six divisions with 16 submarines, taking into account geographical relations between submarine bases and sea areas where engage in surveillance and interception operation.

        However, early stages of the 1950s, there were strong opposition to have submarine by left wing political party and peoples. They opposed that submarine is an aggressive weapon and violate what is called “Peace Constitution”. By these oppositions, the construction of the submarine was delayed in comparison with the surface combatants, such as a destroyer and escort ship. So, the JMSDF had to ask the assistance for the U.S. navy for the target submarine needed for ASW training. Then fleet type submarine Mingo(SS-261) of U.S. navy was lent, on the basis of the Japan-U.S. Weapon Loan Agreement that was concluded in August 1955 and she was turn-over to the JMSDF and named Kuroshio(SS-501).Thus after 10 year’s interval of defeat of the Pacific War, Japanese new navy ? the JMSDF could hosted the Rising?Sun flag again to the sale of the submarine.

        Thereafter, Kuroshio carry our the duty as the underwater target boat and submarine’s crew OJT(On the Job training) ship, as the sole submarine of the JMSDF for about 5 years until the first domestic submarine come out and take over this role. As there was very strong anti-military feeling among peoples of Japan, the JDSDF could not use the word of submarine, so it was called as “an underwater high-speed target” for budge requirement and public announcements. These feeling still continued and Japanese submarines are still imposed several fateful restriction from the time of the birth to nowadays.

        From FY1958 to FY1977, the JMSDF was reinforcing by Five Years Defense Built-up Program four times, accordance with the Basic Policies for National Defense. This Basic Policies for National Defense include an exclusively defense-oriented policy, and also, adherence to the Three Non-Nuclear Principles, -- “Japan do not make or use any nuclear weapons and do not permit to bring into any nuclear weapon in Japanese territories”, also maintaining firmly the Japan - U.S. security arrangements.

         But in 1970s there aroused the strong opinion that Japan should restrict armament accordance with the world situation of the U.S and Soviet peace talk, the National Defense Policy and National Defense Buildup Program Outline were reviewed in October 1976. Further more as a result of the collapse of the Soviet Union, the defense power of the necessary minimum as an independent state which means not to become over the unstableness in our country periphery and self "becomes the blank of power” was decided by the National Defense Council and approved by the Cabinet in November 1995. Accordance with this new National Defense Buildup Program Outline, first Mid-Term Defense Built-up Plan (FY1980-FY1983) was adopted in December 1979.

        By this new National Defense Buildup Program Outline, defense capabilities and major units and main equipment of the JMSDF were again reviewed, and due to the deterioration of finances, necessary expenses were significantly reduced in December 1997. The submarine forces were also reviewed by this new National Defense Buildup Program Outline, but six divisions sixteen submarines were maintained, thought about 10% of the JMSDF forces were reduced by the policy of streaming, making it more efficient and compact.

Oyashio class: First home built submarine        

The early Oyashio I - only submarine in class - launched 1959. 

Following Japan receiving USS Mingo recommissioned as Kuroshio above in 1955 Japan considered whether to build three types of boats, 1,000 tons class (10 knot on surface, 20 knot submerged), 500 tons class (9 knot on surface 17 knot submerged) or 250 tons class (9 knot on surface, 13 knot submerged). The three plans were examined by the Under Water Weapon Study Committee of the Maritime Staff Office.

However, at that time it was difficult to achieve 20 knots submerged underwater due to lack of space for large sufficiently powerful engines. Finally the 1000 tons option was adopted in December 1957 by the Maritime Staff Office. Construction of Oyashio began at the Kawasaki Heavy Industries Ltd (KHI). Kobe Shipbuilding Yard from December 1957. Oyashio was launched in May 1959 and after half year’s sea trial, Oyashio was commissioned in June 1960, as the name of Oyashio (SS-511).

During construction there were many difficulties partly because Japan had not built a submarine since 1945. The basic design was adopted from the high-speed WWII I-201 class. Oyashio was 1,157 tons  surfaced, 79 m long,  diesel 2750 horsepower, 6000 horsepower and 19 knot submerged. WWII Imperial Navy technology such as the automatic depth holding system was adapted, but the snorkel and other new devices were introduced from the U.S. navy. Technicians and and submariners visited the US Navy, and learned not only technology, but also submarine operation and tactics.

The JMSDF learn from the U.S. navy and also the submariners were tamed to the devices and system of the U.S navy through the Kuroshio, so if there was not big difference between Japan and America, applied the U.S. navy’s methods. During the construction increased 130 tons, and finally displacement became 1130 tons. She equipped four tubes for 533mm torpedoes. Power system was diesel-electric, two diesel Kawasaki MAN type of V8V22/30MATL, 2700 horsepower, two main motors of 5900 horsepower and two shaft, speed was 13 knot on surface, 19 knot in underwater , the battery was 4 groups of 120 cells. NS 46 high tension steel was used in hull, this high tension steel NS46 means 46kg pressure on 1mm square.

        On that time, as there were no training facilities for submariners in Japan, there aroused a demand to dispatches submarine to Hawaii to use the U.S. navy’s training facilities, and to learn tactics. This training is continued from 1968 to now and expanded to the LimPac Exercise including not only submarines, but also surface ships and air plain to improve tactical level and closer relations between the JMSDF and the U.S. navy.

Characteristics of Oyashio
● Displacement 1130 ton(double hull) NS 46 high tension steel.
● Length 79 m×beam7.0 m×depth 5,9 m×4,6m, L/D(Length/Depth Ratio) 13,4,
● Power Plant:Diesel-electronic, 2 diesel engine(Kawasaki V8V24/30AMTL) 2700 horsepower 13 knot on surface, 2 main motor 5900 horsepower 19 knot in submerged(Battery 120 set 2 groups)
● Armament 533mm torpedo tubes x 4
● Complement 65
● Contractor Kawasaki Heavy Industries Kobe

Remarks 1:The name of submarine of the JMSDF was name after from oceanographic phenomenon of “Shio(Tide)” in Japanese
Remarks 2: Submarine is constructed at the ex-Imperial navy’s main submarine Contractor of the New Mitsubishi Heavy Industries Kobe and the Kawasaki Heavy Industries Kobe alternately at a rate of one per two years in fiscal year.

Hayashio/Natsushio class: Small type submarine

The plans for next submarine Hayashio (SS-521) above begin with 700 tons but it become 750 tons, and first Hayashio class boats begin construction in June 1960 at New Mitsubishi Heavy Industry Kobe and lunched in June 1962, other was constructed by Kawasaki Heavy Industry in Kobe in June 1960 and also lunched in June 1962, and two more Natsushio class boats constructed in 1963. Hayashio class was firstly esteemed for coastal defense and for blocking the three straits as a attack-submarine(SSK) in war time, and also aimed to be under-water target submarine for ASW training in the peace time.

        The speed decreased 14 knot in submerged with 2300 horsepower and surface 11 knot with 900 horsepower. Battery system was 120 shell and 2 groups. Due to the small boat, torpedo tubes were limited only six, but from this class hydrographic launching tubes were introduced from air launching tubes. Also from this class, two sonar systems were adopted, one is passive bow sonar, and the other was active sonar under the sail covered by FRP dome for ranging. The big difference of Hayashio and Natsushio is length, from Natsushio class canning tower were expanded 1.5 m for astern and overall length became 59m to 61m and displacement increased 790 tons.

        The JMSDF constructed three classes of ten submarines by the First(FY1958 - FY1962) and the Second (FY1962 ? FY1967) Defense Built-up Programs. But, as Hayashio was constructed after long blank of construction, there were many malfunctions and troubles, and that Hayashio class was too small for stable snorkeling in the rough sea around Japan, and also as restricted in endurances capability because of poor habitability. By theses reasons, small size submarine 750 ton class were not considered in Japan after Hayashio class. Hayashio class constructed 4 boats,

Characteristics of Hayashio (Natsusio) class 
● Displacement 750 (790) ton (double hull, partly single in astern section), NS 30 high tension steel
● Length 59(61) m×beam 6,5 m×depth 6,4×draft 4,1m, L/D 9,2
● Power Plant Diesel-electronic, 2 diesel engines(Mitsubishi Kobe 6LDA25B), 900 horsepower 11 knot surface, 2 main motors, 2300 horsepower 14 (15)knot in submerged(Battery 120 set 2 groups)
● Armament 533mm torpedo tubes x 3
● Complement 40

Hayashio(SS-521) (Commissioned 1962)(Decommissioned 1977) (Mitsubishi)
Wakashio (SS-522)(Commissioned 1962)(Decommissioned 1979)(Kawasaki)
Natsushio(SS-523)(Commissioned 1963)(Decommissioned 1978)(Mitsubishi)
Fuyushio(SS-524)(Commissioned 1963)(Decommissioned 1980)(Kawasaki)

Ooshio/Oshio/Asashio Class: Ocean type submarine 

Oshio (SS-561)

Asashio (SS-562)

From operational experiences of small submarines, these small submarines were lacking operational stability in the rough sea, especially in snorkeling. Next submarine was considered for large multipurpose submarine for patrol, surveillance, reconnaissance and crew’s training. Ooshio/Oshio  class above went to the sea in March 1965, then Asashio of 1650 tons improved type of Ooshio was commissioned in October 1966.

      By enlargement of displacement, eight 533mm torpedo tubes in bow and two short range homing torpedo tubes in stern which aimed as the counter-attack for anti-submarine ships(Later short range torpedo tubes were take off). Bow Torpedo tube became from air pressure launching to hydraulic launching. New steering and engines automation systems and auto-course holder were adapted. From this class provided a steering system became aircraft type stick control at the diving stand.

        This class was expected, as an underwater target use, so boat was esteemed high speed to carry out may services with a few submarines, so compromised with 18 knots in underwater with main motor of 6300 horsepower, 14 knot on surface with Man V8V24/30AMTL 2900 horsepower, two shafts. From these reasons underwater performance as a submarine was not realized until appearance of tears drop submarine. The L/D ratio become 11,7 in this class while Hayashio class was 9,2. From Asashio class screw propeller become 5 blades and safety depth increased by high tension steel NS 46.

 Charactlistics of Ooshio/Oshio/(Asashio)class

● Displacement:1600(1650) ton (double hull, partly single in astern section),NS 46 high tension steel
● Length 88 m×beam 8,2 m×depth 7,5×draft 4,7(4,9)m (L/D 11,7)
● Power Plant:Diesel-electronic, 2 diesel engines(Kawasaki V8V24/30AMTL), 2900 horsepower×2 14 knot on surface, 2 main motor 6300 horsepower, 18 knot in submerged(Battery 120 set 4 groups)
● Armament 533mm torpedo tubes×8, 533mm Anti Submarine Torpedo×2 astern
● Complement 82

Ooshio (SS-561) (Commissioned 1965)(Decommissioned 1981)(Mitsubishi)
Asashio (SS-562) (Commissioned 1966)(Decommissioned 1983)(Kawasaki)
Harushio(SS-563)(Commissioned 1967)(Decommissioned 1984) (Mitsubishi)
Michishio(SS-564)(Commissioned 1968)(Decommissioned 1985) (Kawasaki)
Fuyushio(SS-565)(Commissioned 1969)(Decommissioned 1986) (Mitsubishi)

Uzushio class: The first tear drop type submarine 

Uzushio (SS-566)

Uzushio class was the historic mile stone for the Japanese submarine that changed the application of the submarine which esteemed the surface ability than underwater ability. Ten kinds of models were made, to design the hull that demonstrated underwater performance, and conducted the water tank experiment to collect data for design of submarine figure and could get tears drop type submarine with one axis, L/D changed from conventional submarine 11,7(Oyashio class) to 7,1 in tear drop type. Also, the development of new steel necessary to expand safety depth was started.

        First boat of the Uzushio class began construction in January, 1971 and seven boats were constructed in the Third Defense Build-up Programs (FY1967-FY1972), and the Fourth Defense Build up Programs (FY1972-FY1977). By the adoption of tears drop type, underwater performance increased largely in comparison with the conventional submarine. Power plant was diesel-electric propulsion with two Kawasaki MAN V8V24/30AMTL diesel engines and speed was 12 knot by 3400 horsepower, output of main electric motor was 7200 horsepower, and estimated speed was 20 knot pulse in the under water. Battery became 240 set 2 groups from this class.

       New high tension steel NS63 was used on hull to increase the safety submerge depth to 300m(est). Increased tonnage brought space, deck becomes three layers, and this improved not only habitability of performance but also could equipped many devices. Carbonic acid gas absorbent air cleaner, the emergency blow system(Main blow tank), installation of spare torpedo, and could equipped the steerage device, trim and depth adjustment automatic controller, automatic direction holder, and automatic steerage of three dimensions.

       From the Uzushio class increased tonnages to 1850 ton, torpedo tube in bow was removed to the mid-ship section to install large sonar ZQQ-1 in bow(from Isoshio ZQQ-2, from Takashio ZQQ-3), also plane removed from bow to the sail. This plane arrangement was characteristic of the teardrop style submarine. In Japan, when the Uzushio was commissioned (in 1971), some members of the opposition pursued an issue in the Diet that the JMSDF was aiming to use nuclear propulsion for submarine and that this was contrary to the "The three Non-Nuclear Principles". This stemmed from the belief that if an engine was nuclear powered the submarine would become a  nuclear submarine easily.

 Characteristics of Uzushio class
● Displacement:1850 ton(double hull, partly single in astern section),NS46 high tension steel
● Length 72 m×beam 9,9 m×depth 10.1 m×draft 7,5m(L/D 7,1)
● Power Plant Diesel-electronic, 2 diesel engines(Kawasaki V8V24/30AMTL), 3400 horsepower 12 knot, 1 main motor 7200 horsepower, 20 knot in submerged
● Armament 533mm torpedo tubes×6
● Complement 75(80 Takashio and Yaeshio)

Uzushio (SS-566) (Commissioned 1971)(Scraped 1987) (Kawasaki)
Makishio(SS-567) (Commissioned 1972) (Scraped 1988) (Mitsubishi)
Isoshio(SS-568) (Commissioned 1972)(Converted ASU-8001 1989)(Used as a target of
new torpedo and then scraped in 1992) (Kawasaki)
Narushio(SS-569)(commissioned 1973)(Converted ASU-8002, 1990)(Scraped 1993)
Kuroshio(SS-570)(Commissioned 1974)(Converted ASU-8003 1991)(Scraped 1994)
Takashio(SS-570) (Commissioned 1976)(Converted ASU-8004 1992)(Scraped 1995)
Yaeshio(SS-572) (Commissioned 1978)(Converted ASU-8005 1994)(Scraped 1996)

Yushio class: Second Tear Drop type Submarine 

Yushio class (SS-573 onwards)

Yushio class submarine was the second generation of tear-drop boats, from FY1975 to FY1985, 10 boats were constructed. This class is double hull structure and used new high tension steel NS80 and safety depth increased 400m(est). The main engines are Kawasaki MAN V8V24/30ATMTL type, 12 knot at snorkel, and 20 knot in the water. From this class, high capacity new battery were installed, screw rotation are lower than Asashio class with five blades husky propeller. Automatic steerage system of three dimensions, automatic depth and direction holder system were equipped. VLF communication was also possible, net-work-centric combat systems were incorporated in operation room, which enhance adaptability of operations.

        Serial improvement were tried on Yushio class, while constructing 10 boats, from 1984 Nadashio (SS-579) equipped Harpoon missiles launcher with 533mm torpedo tube, by this new system, displacement increased 50 tons and become 2250 tons from 2200 tons. From 1981 Mochishio(SS-574) installed masker, in 1987 from Okishio (SS-576) equipped TASS(Towed Array Sonar System), Hamashio(SS-578) installed modified bow sonar ZQC-4 and attack sonar(active) in the sail in 1986, inertia navigation system was adapted in 1991, sixth boats are still active among ten constructed.

       The reason why Japanese submarine increased displacement constantly are installation of many kind of the weapons aiming a various functions for one submarine, as the total number of submarines are limited within 16 by the National Defense Buildup Program Outline. By this limitation, the JMSDF must decommissioned all boat which passed 16 years then assigned reserve, consequently all Japanese boat served sixteen years of front line, then assigned an axially training submarine for three years, then scraped and finished 19 years life. Furthermore as Japan strictly adopts a firm policy of banning prohibiting the exportation of a submarine or any weaponry, so mass production of auxiliaries equipments are push up high price because of small production, this also enforced effective usages of defense expenditures and oppressing defense budget.

 Characteristics of Yushio class
● Displacement 2250 ton (Complete double hull, partly single in astern part),NS80 high tension steel
● Length 76 m×beam 9,9 m×depth 10,2 m×draft 7,4 m(L/D 7,5)
● Power Plant Diesel-electronic, 2 diesel engines(Kawasaki V8V24/30AMTL), 3400 horsepower 12kt on surface, one main motor, 7200 horsepower 20 knot in submerged (screw 5 high-skew blades)
● Armament 533mm HU603 type tubes for torpedo and Harpoon×6
● Complement 75

Present states of Yushio class (Constructed 10 boats)
Yushio (SS-573) (Commissioned 1980)Converted 1996 ASU-8006(Scraped 1999) (Mitsubishi)
Mochishio(SS-574) (Commissioned 1981)Converted 1997 ASU-8007(Scraped 2000) (Kawasaki)
Setoshio(SS-575) (Commissioned 1982)Converted 1998 ASU-8008(Scraped 2001) (Mitsubishi)
Okishio(SS-576) (Commissioned 1983)Converted TSS-3603(Scraped 2001) (Kawasaki)
Nadashio(SS-577) (Commissioned 1984) (Scraped 2002) (Mitsubishi)
Hamashio(SS-578) (Commissioned 1985)Converted 2002 TSS-3604(Kawasaki)
Akishio(SS-579) (Commissioned 1986) (Mitsubishi)
Takeshio(SS-580) (Commissioned 1987) (Kawasaki)
Yukishio(SS-581) (Commissioned 1988) (Mitsubishi)
Sachishio(SS-582) (Commissioned 1989) (Kawasaki)

Harushio class: Third Tear drop type submarines 

Both above are Harushio class (SS-583 onwards)

The Harusio class is the third generation of the tear-drop submarine construction began from FY1986 to FY1992, and seven boats were constructed. Harushio class followed fundamentally adapted design of Yushio class, but increased 250 tons in displacement. This type was esteems improvement of the underwater maneuverability, expanded search and attack ability. The main motor’s rotation is slower than Yushio class with seven blades high-skew propeller.
          The various measures have been carried out to improve noise and tried to make silent submarine cut on noise of not only main engines but also auxiliary machines. Main engines and main motor were fitted on emission double anti-vibration rubber to reduce of a noise, pipe system, gears, and gaskets were improved, and also snorkel noise are reduced. Harushio class became a considerably quieter boat adapting noise-cut in auxiliary machines, while underwater speed, underwater endurances, safe submerge depth are greatly improved. High tension steel NS110 is adopted with a double shell hull and safety depth is extended 500 m(est). New inverter of electric power transformation(CVCF), which transform of 400 Hz and 60 Hz of the power supply, this help noise reduction and also saving electric power. From this type, torpedo/USM tubes were equipped from constriction stages, fitted with ZQQ-5 sonar system(From Nadashio ZQQ-5B type) combined with TASS and side-array-sonar as a unit. The reception of the communication became possible at the submerged states by the introduction of VLF receiver.

      Length of the ship become longer than Yushio class by 1.2 m and increased 190 tons and become finally 2,490 tons. Main engine are adopted newly developed Kawasaki MAN 12V25/25S, output became 3,100 horsepower, main battery were 240 shells of 2 groups. The IR detection and ESM devices and comfortable habitability of the crew were also improved. For weapons torpedo are changed to Type 89 torpedo in 1989.The tears drop submarine’s construction began from 1971 and constructed 7 Uzushio class, 10 Yushio class, 7 Harusshio class, totally 24 tear-drop boats to the fleet until 1990.

Characteristics of Harushio class

● Displacement 2450 ton(Asashio 2500 tons) (Double hull, partly single in astern part)NS110 high tension steel
● Length 77 m×beam 10.0 m×depth 10.5 m, draft 7.7m(L/D 7.3)
● Power Plant:Diesel-electronic, 2 diesel engines(Kawasaki 12V25/25S, 3400 horsepower 12kt on surface, one main motor 7200 horsepower 20knot plus in submerged
● Armament 533mm Hu603B type torpedo tubes for 89 type torpedo and Harpoon×6
● Complement 75(Asashio 71)
Same type ships(Commissioned)
SS-583 Harushio (November 30, 1990) (Mitsubishi)
SS-584 Natsushio(March 20, 1991) (Kawasaki)
SS-585 Hayashio(March 25, 1992) (Mitsubishi)
SS-586 Arashio(March 17, 1993) (Kawasaki)
SS-587 Wakasio(March 1, 1994) (Mitsubishi)
SS-588 Fuyushio(March 7, 1995) (Kawasaki)
SS-589 Asashio(March 12, 1997) Converted TSS-3601(March 2000) (Mitsubishi)

Oyashio type: Cigarette type submarine

Both above are Oyashio class (SS-590 to SS-600)

Oyashio class is the successor of the Yushio class, and the first submarine of the cigarette type submarine in the JMSDF. While planing Harushio, there began two studies for next submarine. One is material for secrecy from active sonar to absorb reflection. Another is automatic steering, trim control system which were also carried out in parallel in these studies. From 1991 to 1992, integrates submarine operation(Fire control) system was discussed by the Next Term Submarine Technology Examination Committee, member of a committee was Technical, Equipment, Defense Department of MSO, Submarine Fleets and Technology Research Center. These studies are applied to new tactical integrated operation(fire control) system.

        From this class to improve search ability, new ZQQ-5(from Michishio ZQQ-5B, Makishio ZQQ-6) sonar was equipped in bow and passive detecting sonar was top of the sail. Also developed array sonar fitted on hull and TASS sonar was fitted astern part. By these sonars capability of the detection in a long-distance was greatly expanded. Main engine is same as Harushio class, but output of main motor is increased 550 horsepower. From Arashio(SS-586) screw changed 5 to 7 blades with high-skew propeller. For weapon new 89 type torpedo and six torpedo/USM(Harpoon) combined tube are in bow and two automatic mine launchers are fitted on stern part. The big different of Oyashio class is changed hull structure to the simple shell partly from double shell with new high tension steel NS110. Torpedo tubes in bow were removed to mid-ship section, and for anti-detection stealthy for reflection hull is slanted and also sail is covered noise absorptive tile. Main engine is same as Harushio, Kawasaki 12V25/25S, but output power increased 550 horsepower.

       Construction of the first Oyashio class began January 1994, and commissioned in March 1998, and now six are in active and more two are under construction. During construction, in 2000 from Uzushio (SS-594) the solid aminn carbonic acid gas absorption device was adopted, and from Isoshio(SS-593) floating antenna was introduced. From 1960 to now the JMSDF constructed 40 diesel powered submarine, 10 were pre-tear-drop type boats, 24 were tear-drop type boats and 6 were cigarette type boats. But as there is the restriction of "The Non-Nuclear Three principle", nuclear engines are not allowed to use, so the JMSDF started next population Project of the AIP (Air Dependent Propulsion) engine from 2000, installing Stirling engine of the Swedish Kockums Co. ITD. , fitted on Asashio (TSS-3601) and started test from December, 2001.

Charactlistics of Oyashio class
● Displacement: 2750 ton, (double hull partly simple hull in astern)NS110 high tension steel)
● Length 82 m×beam 8,9 m×depth 10.3 m×draft7.9m(L/D 8,0)
● Power Plant Diesel-electronic, 2 diesel engines (Kawasaki 12V25/25S, 3400 horsepower 12kt on surface, one main motor one shaft 7700 horsepower 20k plus submerged with 7 blades propeller
● Armament 533mm type 87 torpedo Hu603B type tubes with Harpoon×6
● Complement 70

Same type of boat   (Commissioned)    (Company built by)
SS-590 Oyashio      (March 16, 1998)   (Kawasaki)
SS-591 Michishio   (March 10,1999)    (Mitsubishi)
SS-592 Uzuishio     (March 9, 2000)     (Kawasaki)
SS-593 Makishio    (March 29, 2001)    (Mitsubishi)
SS-595 Isoshio        (March 14,2002)    (Kawasaki)
SS-595 Narushio     (March,15, 2003)    (Mitsubishi)
SS-596 Kuroshio    (March 8, 2004)       (Kawasaki)
SS-597 Takashio    (March 9, 2005)       (Mitsubishi)
SS-598 Yaeshio      (March 9, 2006)      (Kawasaki)
SS-599  Setoshio    (February 28, 2007) (Mitsubishi)
SS-600  Mochishio (March 6, 2008)      (Kawasaki)

Soryu type: Cigarette type submarine

Both above are Soryu class (SS-501 onwards)

The Sōryū-class submarines (16SS) are diesel-electric submarines that entered service with the Japan Maritime Self-Defense Force in 2009. The design is an evolution of the Oyashio class submarine, from which it can most easily be distinguished by its X-shaped tail planes. The Sōryūs have the largest displacement of any submarine used by post war Japan.

At 84 m long and 4,200-tons submerged, Soryu is significantly larger than the original 11 Oyashio-class boats (81 m and 3,500 tons), in order to incorporate a Kockums Stirling air independent propulsion (AIP) system. With the Kockums Stirling AIP system the submarine doesn't have to surface to charge the batteries and thus increases the submerged endurance from days to weeks. Components for the AIP, which will enhance the vessel's stealth and special operations capability, were supplied by the Swedish company for assembly in Japan.

The Soryus design features higher automation (particularly in combat systems) and computer-aided X control planes. The revolutionary X rudder configuration was first developed by Kockums for the Swedich Gotland-class. The X rudder provides the submarine with extreme manoeuvrability and also enables it to operate very close to the seabed. The Soryu's hull is clad in anechoic coating and the interior features sound isolation of loud components. An anechoic coating has a major effect on the avoidance of detection. 

The Soryu was was launched at Mitsubishi Heavy Industries (MHI's) Kobe shipyard on December 2007 and commissioned in March 2009. It was formerly known as the "SS 2,900 ton" and the "16SS" project as it originated in the 16th year of the current Emperor's reign (2003).

The cost of the sixth Soryu ( the "Kokuryu") was estimated at 540 US$ million.

Japanese submarines since World War II were named after ocean currents. However, the JMSDF changed its naming convention with the Sōryu and submarines will now be named after mythological creatures. Sōryū (そうりゅう) means blue (or green) dragon in Japanese.

Characteristics of Soryu class (main source)

Surfaced: 2,900 tonnes (2,854 long tons)
Submerged: 4,200 t (4,134 long tons)
84.0 m (275 ft 7 in)
9.1 m (29 ft 10 in)
8.5 m (27 ft 11 in)

Steel - Japanese Ministry of Defense Standard Naval Steel (NS)80 and NS110
1-shaft 2× Kawasaki 12V 25/25 SB-type diesel engines diesel-electric
4× Kawasaki Kockums V4-275R Stirling engines
3,900 hp (2,900 kW) surfaced
8,000 hp (6,000 kW) submerged
Surfaced: 13 kn (24 km/h; 15 mph)
Submerged: 20 kn (37 km/h; 23 mph)
65 (9 officers, 56 enlisted)
Sensors and
processing systems:
ZPS-6F surface/low-level air search radar
Hughes/Oki ZQQ-7 Sonar suite: 1× bow-array, 4× LF flank arrays and 1×Towed array sonar
Electronic warfare
& decoys:
Combat System locally designed and built. ZLR-3-6 ESM equipment
2× 3-inch underwater countermeasure launcher tubes for launching of Acoustic Device Countermeasures (ADCs)
6×HU-606 21 in (533 mm) torpedo tubes with 30 reloads for:
1.) Type 89 torpedoes
2.) UGM-84 Harpoon

The Soryus are envisaged to be a class of ten. As at January 2015 five AIP equipped Soryus (which I call Soryu 1s) had been Commissioned. One more AIP Soryu/Soryu 1 is due to be Commissioned in March 2015. 

While the first six Soryus (SS-501 to SS-506) utililize AIP the Soryus from SS-507 onwards are expected to be "improved" Soryus . The "improved" Soryus are expected to have no AIP, no lead-acid bateries, but instead Lithium-ion batteries. I call these improved Soryus "Soryu 2s". One report of September 29, 2014 indicates: "Six of 10 Soryu-class submarines which take about four years to build...have been completed. Japan’s Defense Ministry has just requested 64.4 billion yen (US $589.5 million) to start building [four Soryu 2s, starting with SS-507] from April 2015, and this — and three other boats — will use Lithium-ion batteries."


See regular SORYU TABLE updates on Submarine Matters - latest update is on November 6, 2017 with 26SS being named Shyuriyu. Soryu 16SS can be called "Soryu Mark 1s" with Stirling AIP. Future Soryu 28SS can be called "Soryu Mark 2s" with no Stirling AIP but they will have Lithium-ion batteries (LIBs). 

LAB or LIB & AIP *
Laid Down
Sōryū (そうりゅう) / Blue Dragon
March 2005
Dec 2007
Unryū (うんりゅう) / Cloud Dragon
March 2006
Oct 2008
Hakuryū (はくりゅう) / White Dragon
Feb 2007
Oct 2009
Kenryū (けんりゅう) / Sword Dragon
March 2008
Nov 2010
Zuiryu (けんりゅう) / Sword Dragon
March 2009
Oct 2011
Kokuryū (こくりゅう) / Black Dragon
January 2011
Oct 2013
Jinryū (じんりゅう)/ Benevolent Dragon
Feb 2012
Nov 2014
Soryu Mark 2 
LIB only
LIB only
LIB only

 1st Australian class?

* LAB means Lead Acid Battery, LIB is Lithium-ion Battery, AIP is Air Independent Propulsion

29SS will be a new submarine class (no longer called Soryu). 

New features for the Next-Generation Submarine - 29SS - may include:
-  A more effective and powerful snorkel generation system for recharging the LIBs.
-  A next generation sonar system
-  Introduction of the Next-Generation heavyweight torpedo known as G-RX6.
-  An improved platform to reduce vibrations. This platform will be more impact resistant.

Submarine Organization

In February, 1960 in accordance with the increase of submarines, submarine base was opened at Kure in the Inland Sea of western part of Japan, in there Kure Submarine Education Department was established as the attachment of the Kure Submarine Base. In 1961 submarine rescue ship ASR Chihaya (1340 tons diving bell type) was commissioned and in August 1962, the First Submarine Division was formed to conduct submarine operation and submarine rescue operation. In February, 1965 accordance with increase of submarines, the First Submarine Division reformed to the First Submarine Flotilla.

In 1981 along with the reinforcement of the submarines, the Submarine Fleet was newly formed in Yokosuka, under the Self Defense Fleets with the 1st and 2nd submarine Flotilla, the Submarine Education and Training Division(SETD) and the 1st Submarine Training Division. The Submarine Fleet commander is responsible to all operations of submarine including the submarine rescue activity and also unification of submarine tactics. Each submarine flotilla consists of a submarine base and 2 or 3 submarines divisions. The Submarine Flotilla Commander is type commander and responsible to the training, the Submarine Base commander is responsible for logistics support.

Submarine Education and Training Division(Kure Base) has a detachments in Yokouska, Submarine Education and Training Division has Submarine diving simulation trainer, Submarine Tactics Simulatio Trainer and navigation Simulation trainer which help level up of tactical skill. Yokosuka Tactics Support Division (YTSD) operate DSRVT (Deep Submergence Rescue Vehicle Trainer) for rescue crew of DSRV craft. The escape training installation and fire-water fighting facility located at the First Service School (Etajima) in the Inland Sea, opposite side of the Kure Submarine Base.

Submarine Organization Chart (at March 28, 2015)

Note that Japan intends to expand its submarine fleet to 22 active submarines - in doing so creating a new Division.

Submarine Fleet Headquarters (Yokosuka)

nodate of
ranknameclassprevious jobnext jobnote
1628 Jul 2005Vice AdmiralSugimoto Masahiko18th class, NDA
172 Nov 2007Vice AdmiralKobayashi Masao17th class, NDA
1824 Mar 2009Vice AdmiralNagata Mikio20th class, NDACommander, Sub Area Activity Hanshinretired
1927 Apr 2011Vice AdmiralYano Kazuki22nd class, NDADir, Equipment Dept, Maritime Staff Officeretired
2022 Aug 2013Vice AdmiralKaji Masakazu24th class, NDASuperintendent, JMSDF 1st Service Schoolincumbent

The Soryu, Oyashio and Harushio classes to scale.