AUKUS SSNs With Nuclear Weapons

I’ve long argued that its of little use Australia has SSNs as a China deterrent. 

This is if our SSNs are merely armed with torpedoes, Harpoon and/or Tomahawk subsonic SLCMs and mines. These would only add up to a total “throw weight” of 25 tonnes of high explosive, maximum. Land attacking China merely with high explosive, subsonic, SLCMs would result in many/most being shot down, fail to deter China, but just make China more angry.

Australian SSNs need sufficient vertical tube versatility to be armed with hypersonic missiles of various sizes, or even ballistic missiles.

So it is by good fortune that the US SSN(X) debate is publicly leaning (on Nov 10, 2022) towards larger (therefore more costly) 9,000 tonne Seawolf sized SSNs/SSGNs. The Seawolf Mark I’s beam/diameter is 12m permitting a longer/taller missile than the Virginia’s diameter of 10m.

Hypersonic Missiles on Block V Virginias & SSN(X)/Seawolf Mark IIs

There appear to be plans to deploy Hypersonic Missiles on Block V Virginia SSNs and presumably on not yet diameter designated SSN(X)/Seawolf Mark IIs (but likely of 12m-13m diameter).

Looking at USNI News (Nov 3, 2022) it seems the USN sees it possible that 3 x  Common Hypersonic Glide Bodies (C-HGB) and their boosters could fit in each of 4 Virginia Payload Tubes (VPTs) of 2.2m diameter, behind the sail, by 2029. That is 12 x C-HGBs per Virginia, Block V (the first being USS Oklahoma (SSN-802)).

As hypersonic submarine cruise missiles are new weapon categories under development there is no concrete doctrine (yet) as to whether they can be assumed to have conventional or nuclear warheads.

Meanwhile, the 2 VPTs in front of the Block V's sail may not have the versatility/position to be lengthened - so may be still restricted to subsonic Tomahawk SLCMs.

SSN(X)/Seawolf Mark IIs Capable of Taking 4 Trident IIs?

The 2.2m diameter of VPTs originated from the 2.2m diameter of the originally Trident II silos on the 4 Ohio-class that became SSGNs. Those silos were then converted to each take 7 x Tomahawk missiles. The 7 Tomahawk accommodating diameter was then carried over as VPTs to Virginias.

It is highly likely the VPT will be carried over to the SSN(X)/Seawolf Mark II.

So Trident II SLBMs, at 2.11m diameter, can horizontally fit into a 2.2m Virginia Payload Tube (VPT), but not vertically (yet). 

But vertically? Where I'm going with this is if a Seawolf Mark I’s hull diameter of 12m is only increased by 1m for an SSN(X)/Seawolf Mark II that would make a diameter of 13m.

13m just happens to be the diameter of an Ohio SSBN and planned 13m diameter of a future Columbia SSBN. These, of course, can/will vertically fit a Trident II’s 13.58m height owing to their slight hump.

This would give SSN(X)/Seawolf Mark IIs of 13m diameter and with 4 VPTs the capability to accommodate 4 x Trident IIs.

This might be a future capability much valued by Australia - if its 8 future SSNs happened to be US SSN(X)/Seawolf Mark IIs. Fear of China has made possible the unprecedented AUKUS SSN offer. Increasing fear of China (say, in 2030) may swing the Australian public in favour of an Australian nuclear deterrent.

If Australia chooses the UK, perhaps UK SSN(R)s might have the same SSN(X)  (aka common AUKUS) dimensions enabling a Trident II capability.

This thought should not be confused with the nuclear armed Tomahawk TLAM-N debate. Tomahawks, against a nuclear armed enemy, carry with them the "is it carrying a conventional or nuclear warhead"  ambiguity-misunderstanding. There is no such ambiguity-misunderstanding with SLBMs as they are always assumed to be a nuclear tipped deterrent.

Huge Problem Nuclear Qualifying RAN: Report

Australia’s Nautilus Institute has produced a very up to date “Peace and Security Special Report”:

Titled “AUSTRALIA’S FUTURE SUBMARINES: AN EXPLAINER”

By Allan Behm, Rear Admiral Peter Briggs (Retired) and Commodore Paul Greenfield (Retired)

Dated November 16, 2022

At https://mailchi.mp/nautilus/napsnet-special-reportaustralias-future-submarinesan-explainer?e=1a4f758957

Its 33 pages contain a wealth of knowledge, that former senior naval officers are best placed to provide, about Australia’s submarine needs.

At the moment I’m focusing on the main section on nuclear propulsion, which states in part:

“Nuclear reactors also radically change the power available to submarines, their endurance underwater, the transit times and time on station, as well as the “hotel” services available to submarines and their crews. Combat system capability, habitability, air quality, water availability and general amenity are much enhanced. There is much to be said for nuclear propulsion, especially when the submarine’s survivability and that of its crew is taken into account. The cost multiplier, however, may not match the force multiplier effects.

Nuclear propulsion would also raise a host of new and imponderable issues for Australian industry, and for the RAN’s ability to support the submarine. Lacking a nuclear industry—and thus the education and associated skills streams that support such an industry—Australia would necessarily have to develop the education, infrastructure and industrial support needed to maintain the capability as part of the cost of that program. It would be important that Australia develop a sovereign capability in all these areas, as the availability of third parties in a time of tension is moot.

At present, the Royal Australian Navy (RAN) has no nuclear qualified personnel. The nuclear-powered attack submarines (SSNs) and the ballistic missile submarines (SSBNs) in service with the USN and the Royal Navy require between 40 and 50 crew members qualified at varying levels of nuclear expertise per boat, with considerable numbers of similar personnel in the logistics and support functions ashore. Maintaining the pipeline of nuclear-trained personnel in the US or the UK will be costly—approximately $1 million per person per year. Establishing and maintaining a similar pipeline in Australia will not be significantly less expensive.

In June 2022, the US House of Representatives introduced legislation that would assist the RAN to train its future submarine operators in the US: the Australia-US Submarine Officer Pipeline Act will permit at least two Australians to train in the US each year.[15] This is an important, but ultimately token, effort. The pipeline will need to be as wide as it is long to remediate the shortfall in the RAN’s skill base.

It is important to recall that the UK and USA established their SSN capabilities in the circumstances of the Cold War, drawing upon a large force of conventionally powered submarines and steam powered surface ships. This situation assisted in providing the essential manpower and skills base. Nonetheless, the task was a serious challenge for each navy.

Australia has none of these resources and will have to draw heavily on the supplier navy’s training system and seagoing submarine force to train its personnel. The availability of the necessary level of support would be a major risk for an Australian SSN program, and one that needs early resolution.

Equally importantly, the numbers and skillsets in an SSN crew are significantly different to that of a Collins crew. The training program would entail converting existing RAN submarine personnel and a substantial initial training program. Both would require long periods of training and overseas service to gain the necessary experience. Until Australia’s SSN force reached sufficient operational submarines to undertake the at sea training of trainees (say, at least six SSN) most of this training would have to be conducted overseas - and it would take about 20 years to deliver this number of SSNs after initiating the program.

At this point, RAN schools and a nuclear engineering faculty established within a selected Australian tertiary institution could finally begin to take over this task. But in the absence of any nuclear power generation industry in Australia, the cost of establishing and operating this training infrastructure would be borne by the SSN program.

The problem is enormous.”

Japanese hypersonic cruise & glide missile progress

Below is an interesting wispywood2344 comment of November 13, 2022:

[Since the October 10, 2022 article] there has been a follow-up report [1] on the news of Japanese long-range missiles. 

According to this report, both the "hypersonic cruise missile (HCM)" and the "highspeed glide missile (HGM) for island defense Block 2" have a range of over 1,000 km. 

This is the first time that the range of a HCM has been reported. 

The range of the HGM was said to be 500 km [2] but this is apparently the range of the "rapidly-deployable" Block 1.

Block 1's range of 500 km realizes "inter-island" firing from Okinawa main island to the entire Nansei islands, but is not enough to cover the Taiwan Strait.

Block 2's range of 1,000+ km will not only realizes "island-to-mainland" firing, i.e., from Okinawa main island to the west coast of the Taiwan strait, but also "inter-mainland" firing, i.e. from Kyushu to Shanghai. 

[1] Sankei-Shimbun (newspaper), "[Exclusive] The Japanese MoD considers to procure 1,500 long-range [hypersonic cruise missiles (HCM)] within 10 years" dated November 6, 2022 [In Japanese. Just right click mouse to translate]. https://www.sankei.com/article/20221106-WRI5DOYKCJMM7FMDMB3LY53IQI/

[2] Mainichi-Shimbun (newspaper), "The Japanese MoD considers installing an anti-aircraft-carrier warhead on the highspeed glide missiles (HGMs) for island defense, as well as increasing their speed and range". dated February 25, 2020. [In Japanese. Just right click mouse to translate. Glide missiles of this type generally reach hypersonic speed. See diagram below]. https://mainichi.jp/articles/20200224/k00/00m/010/219000c

Diagram courtesy Mainichi-Shimbun February 25, 2020.
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China's Longer Range JL-3s Allegedly on Type 094 SSBNs

China allegedly has longer range JL-3s on its six Type 094 (NATO designation Jin class) SSBNs. This is according to former naval aviator US Admiral Sam Paparo (Commander US Pacific Fleet) in the Japan Times, November 19, 2022.

Pete Comment

Other sources indicate at least one Type 094 has been modified (as a prototype fitout) to take the JL-3. The JL-3 might be slightly taller and of greater diameter, than already 13m JL-2s. If diameter has been increased then the hitherto 12 silo 094 might have experienced a reduction from 12 x JL-2s to 10 x JL-3s. Other 094s are being considered for similar JL-3 modifications. But full deployment, with 12 to 16 x JL-3s, will likely need to await completion of the Type 096s.

The JL-3 SLBM may have a range of 10,000-12,000km (average to lighter payloads) allowing 094s, in the Chinese protected South China Sea, to hit some of the continental US and all of Australia.

Geography and reputed noisiness of 094s (part owing to their pronounced hump - photo below) restrict them to operating in their near China coast bastions. 

If they could operate from a captured Taiwan, then quieter, future (13m beam, slightly humped) Type 096s might be able to operate in the mid Pacific - a launch area that could take in all of the continental US.

(Likely Type 094 photo. Courtesy US Government, 2014)

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France not offering Australia SSNs, only SSKs.

Unfortunately France at the highest level (President Macron) is criticising Australia’s plans to buy SSNs, as Macron claims this risks increasing tensions with China. See the Australian Financial Review's November 18, 2022 report or, if paywalled, see this report.

This means France is not offering Australia SSNs, only SSKs. 

This is specifically indicated by a France 24 report of November 17, 2022 where President Macron "said France would not supply nuclear submarines to foreign countries, so the offer related only to conventional vessels. 

[President Macron] added it would guarantee Canberra's "freedom and sovereignty", noting that construction would be in Australia."

Comments on Nov 11 & 17 articles. Sonars.

Anonymouses "Japanese Submarine LIB distributions & other calculations" of Nov 11, 2022 generated many comments. 

Those are the comments not incorporated into the much better "REVISED Japanese Sub LIB distributions, Othercalculations" which has excellent diagrams, and is dated Nov 17, 2022.  

Those great comments are below and were made between November 12 & 16, 2022:  

"I'm a different Anonymous commented Nov 12, 2022:

A power load for propulsion of 50 kW is far too low for a 3,000 tonne submarine [like a Japanese Taigei or Soryu MK. II]. 50 kW being more like the power of an Outboard engine for a small amateur fishing boat or probably the power needed for a submarine to barely stay idle in a current.

This is noting the Kuroshio current in the Tsushima Strait is above 5 knots. 300 kW is probably the minimum for a sub, necessary to reach 5 knots.

A simple back of the envelope calculation considering the public data (eg. French Jeumont engines):

-  on the 2,000 tonne S-Br (Brazilian Navy Scorpene) where 2,900 kW is needed to sprint at 20 knots submerged

-  on the Barracuda/Suffren class SSN (5,000 tonnes) where 15,000 kW is needed to reach 28 knots

On the lower length/diameter L/D Taigei at 3,000 tonne, (the power need evolves as the square of the speed) this rule of thumb will lead to 300+ kW at 5 knots. This would mean a week in a real tactical situation which is remarkable

More important is the power density, the shape of the discharge /charge curve and the charging speed (under snorkel) to decrese the indiscretion ratio.

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wispywood2344 commented Nov 13, 2022:

There is a serious clue about the energy capacity of Japanese submarine LIB "SLH" hidden in a document published on the Web by the Japanese MoD.

This is it. [1]

It should look familiar to you.

Display the graph on the page 2 of this document and enter "Ctrl+A," you can reveal the HIDDEN (or FAILED TO BE DELETED) LETTERS on the vertical axis. [2]

Therefore, we can assert that the capacity of a lithium-ion cell used in "SLH" is 1000-2500 Ah.

Since "SLH" uses LCO as the positive electrode material and carbon as the negative electrode [3], the nominal voltage of a "SLH" module is around 37V.

Taken together, the energy capacity of "SLH" can be estimated to be around 36-93 kWh per module. 

[1] FY2006 Post project evaluation "Development of new submarine main battery"

https://warp.da.ndl.go.jp/info:ndljp/pid/11339364/www.mod.go.jp/j/approach/hyouka/seisaku/results/18/jigo/sankou/jigo05_sankou.pdf#page=2

[2]  http://blog.livedoor.jp/wispywood2344/others/SLH_Capacity_Leakage.gif

[3] "Realization of the world's first submarine equipped with a lithium-ion battery system", at Defense structure improvement foundation at https://ssl.bsk-z.or.jp/kenkyucenter/pdf/gyt20201210.pdf#page=2

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An Anonymous commented Nov 14, 2022:

Once, an influential politician on Japanese MoD revealed there was an improved version (SLH2?) of the current lithium-ion battery (=SLH) for submarine, but due to budget constraints, the improved version could not be obtained. 

So, SLH2 might be based on is based on high performance lithium-ion battery for space (energy density 168Wh/kg), while SLH might be based on is based on large lithium-ion battery for space (energy density 140Wh/kg).

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SONARS are High Hotel Load Users

C commented Nov 14, 2022:

I think rather a lot hinges on the hotel load. I read all sorts of numbers from 50 to 200Kwh, but its all very iffy and vague.

My point is that is in all my reading the composition of hotel-load is glossed over, but maybe its worth some drilling down into this? eg: The Thales VELOX-M8 Broadband Sonar Interceptor [Control-F for "sonar" within this Barracuda SSN link] uses up to 400W when running (which I suspect is a max number). One could put some fair estimates on air circulation systems based on industrial HVAC. Ditto for refrigeration. Etc.

I confess I cant really contribute very much to this, I have snippets only, but I think its critical in understanding practical endurance for modern boats - if designers were able to halve the hotel load, they'd double endurance!

eg. There is also the issue that any computational system that generates waste heat, will also need that heat removed, essentially doubling the energy cost (this is the classic cost issue with massive datacenters), ergo a BIG incentive to use highly efficient [digital signal processors] DSPs, [central processing units] CPUs, etc. I suspect most of the big sonar rigs designed by nuclear sub club countries are not overly concerned with power consumption (obviously), but other vendors may (or may not) be far more judicious.

Something to chew on.

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Another Anonymous commented Nov 16, 2022:

The French SSN, Barracuda-class submarine is equipped with the Thales VELOX-M8 intercept sonar [1]. But, a conventional submarine with limited power supply cannot be equipped with this kind of high power consumption sonar [2] and is equipped with low power consumption and less sensitive sonar instead. 

[1] Barracuda SSN Specs: at Very long link :   

[2] SHIPS OF THE WORLD, Special issue 159, page 21, by Ex-Fleet Commander of JMSDF [Japanese Navy] Masao Kobayashi. [scroll down here for his photo and biodata.] Kobayashi said:

“In order to maintain long-term diving, it is essential to reduce the hotel load, and it is necessary to reduce the power consumption of the onboard equipment. This makes a great impact on the onboard equipment. For example, the [Virginia sub's BQQ-10 spherical bow sonar array] generates a uniform sonar beam toward not only in a right and left direction but also in an up and down direction and is very effective. But there is no conventional submarine equipped with the spherical array because the beam generation of this array needs a huge amount of calculations, i.e., huge power consumption.”