Plan Type 093/094 Nuclear Submarine Thread

Discussion in 'Navy' started by SinoSoldier, Nov 22, 2013.

  1. antiterror13
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    antiterror13 Colonel

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    Good point! .... I thought China should have more SSN and SSBN ... I would say 2:1 ratio

    What happens to 095 and 096 ? ... no news recently ?
     
  2. AndrewS
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    AndrewS Senior Member
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    At the moment, Chinese SSNs just aren't quiet enough.

    But afterwards, yes, we'll should see a significant increase in production
     
  3. Biscuits
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    Biscuits Junior Member
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    What’s stopping them from using the Yuan quieting techs on the SSNs?

    I think there’s a funding/priority issue to this. SSNs tend to be slightly louder than same tech SSK counterparts. Their main advantage is range and speed.

    Right now, the only rival that would require range to reach and demand a SSN would be the US navy. If there’s a conflict in Africa, SSNs would not be necessary.

    But the US navy outnumbers the PLAN by so much that any SSNs facing them on the high seas would be swarmed. Ditto for surface navy ships. So the navy remains an Asia defense force, where SSKs are more useful than SSNs.
     
  4. AndrewS
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    AndrewS Senior Member
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    My understanding is that the main issue with Shang SSNs is the nuclear reactor which is really noisy, whereas the Yuan is near silent due to the battery-electric drive.

    As for PLAN SSNs being swarmed on the high seas, the whole point of an SSN is that it is invisible and can easily break contact from pursuing forces.

    Yes, within the First Island Chain, I reckon SSKs are better, given that you could buy 2-3 Yuan SSKs for the price of a single Shang SSN.

    But once SSNs get to Los Angeles level quieting, SSNs should be able to get past the First Island Chain and patrol key chokepoints like Seattle, San Diego, Hawaii, Guam, Panama, Persian Gulf, Suez Canal etc
     
  5. Totoro
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    Totoro Captain
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    Reactor itself shouldn't be noisy. It may require pumps to keep it cool, which produce noise, but there was an article a few years back talking about 093's natural circulation when it comes to cooling of the reactor. So that's another aspect of noise reduced. Further noisemaker is usually the steam turbine. All today's nuke subs have one (or two, when it comes to older types) and one might try to somewhat lower the noise the turbine makes through very precise machinery. That's usually helped by computers, computer aided milling etc. All stuff that China is pretty good at, especially when compared to, say, 1980s levels of such tech in the West.

    Further noise source is gearing mechanism, for which the same issue of computer and fine tolerances can be applied. Then there are various damping mechanisms inside the sub. Those aren't very high tech, one basically needs enough volume to make them work best. (which is why larger, nuke subs, can in some aspects have it easier to keep quiet compared to smaller subs). Basically rafts holding all the machinery separated from the hull, as well as flexible shaft joints and flexible pipes, serving as interfaces between any sort of noisemakers (such as the propulsion unit, Air conditioning etc) and any sort of fixed stations connected to the hull. Those were all first used in 1970s and 1980s and are a quite known quantity. It's unlikely their quality is somehow noticeable inferior to what the west had in 1980s.

    What's left is the screw, which needs to be designed in a proper way, through computer modelling and made with fine tolerance milling machines, so the cavitation generation is kept to a minimum. The West started with those in 1960s but Soviets didn't really catch up there until 1980s. Again, an area that is unlikely to be worse than 1980s Western subs.

    Basically, I see it very unlikely that current best variant of 093 is any noisier than the improved LA class sub. And may actually be even a bit quieter, since LA and improved LA class, due to political and doctrinal reasons of the time, did not feature natural circulation for reactor cooling.

    The "Chinese subs are noisy" claim is something that is really outdated when it comes to newly produced 093 subs. It originated with 091 class which was indeed quite poor. And the initial variant of 093 probably didn't help either, as there are indications that the reactor design changed over time, thus allowing use of natural circulation.
     
  6. AndrewS
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    AndrewS Senior Member
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    The thing is, if the Type-93 was that quiet, I would expect it to be publicly acknowledged given the deterrent effect of knowing there might be such a submarine in the area.

    But given the variety of Type-93 variants we've seen, we can see that they were still continually improving the design just a few years ago.

    However, we've seen the expansion of submarine construction facilities at Huludao. So presumably the next-gen Type-95 will be sufficiently quiet enough for mass production.
     
  7. Totoro
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    Totoro Captain
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    My opinion is that noise levels of subs would NEVER be discussed or hinted at or acknowledged in any way. Foreign intelligence probably knows pretty well how quiet they are. But are equally unwilling to talk. So we're left with organisations such as USNI taking historical claims and publicly available (dubious) data, and interpolating them to the present day.

    Next generation of subs, whether they're called 095 or 093x, is probably going to comfortably quieter than improved LA class. All the stuff i mentioned in my previous post, on top of further computer aided design/manufacture, newer reactor requiring even less cooling and a shrouded propulsor should pretty much approach SeaWolf/early Victoria class when it comes to noise.

    Similar sources to USNI basically upgunned their projections of Soviet sub noise levels in 1980s, once they learned of soviets use of the skewback propeller and natural circulation. all the features contributing to the noise are quite known and can be quantified to a rough degree.
     
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  8. by78
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    by78 Colonel

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    Another magazine scan...

    (2048 x 1448)
    [​IMG]
     
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  9. Anlsvrthng
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    Anlsvrthng Junior Member
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    Question is the maximum silent speed, not the level of noise at a non-disclosed speed, at unknown speed.

    There should be a 3d graph describing the sub noise by frequency, at different speeds and deep.

    And the most problematic is the low frequency noises, those propagating to very big distances.
    http://resource.npl.co.uk/acoustics/techguides/seaabsorption/

    With the same emission power, the 100 Hz propagate 60 times longer distance than the 1000 Hz.

    So the most critical is the shape of the sub, the vibrations generated by the hull itself, and sadly any rotating machine that fall into the range of 1-400 rpm.


    It is not simply machining tolerance, that is small part, but long and painful balancing of every component way beyond the normal requirements ( the rotating machines usually balanced only for the critical frequencies, to survive the spin up/down ).

    Interestingly, the merchant ships has high noise around 50 Hz , so the non-damped submarine could have similar noise maximum.

    The capitation itself can not be a big issue, that can be controlled by deep, and if they push the frequency to higher than 1000 Hz then the they don't need to worry about the emission power.

    I think the key should be the shape of the submarine, the shape of the propeller, and the balancing of the rotating machines.

    https://staff.washington.edu/jan4/porsec_c.htm
    https://www.iqoe.org/sites/default/files/files/Wittekind.pdf
    By these a low frequency noise source can be heard for thousands of kilometres : O
     
  10. taxiya
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    taxiya Major
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    By saying all these, you are telling us the maximum silent speed of 093 being what? And it is worse than whom?
     
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