back to article China building SUPERSONIC SUBMARINE that travels in a BUBBLE

China reportedly wants to enter the world of supersonic transport – under the water. Rather than working up its own successor-to-Concorde project, the South China Morning Post says scientists at Harbin Institute of Technology's Complex Flow and Heat Transfer Lab are working on developing a technique called supercavitation, …

  1. Number6

    Clearly a challenge for the Special Projects Bureau when they've finished conquering outer space - apply their rocketry to inner space.

  2. zenmaster

    Because thats what sea life wants!

    An underwater ballistic missile, scaled up...

    1. Voland's right hand Silver badge

      Re: Because thats what sea life wants!

      Sealife? I did not know that USA carrier groups counted as sealife.

      Though with DF21 from above, this from below and a couple of imported Sunburns launched from cloned (or imported) Su-34s they will definitely be entering the endangered species book (at least as far as the Taiwanese straights and the Yellow sea is concerned).

      1. Levente Szileszky

        Re: Because thats what sea life wants!

        Someone is watching too much Russia Today or Chinese TV propaganda...

        FYI the SSN22 threat was taken care of when Raytheon started shipping SeaRAM, its drop-in 11-missile upgrade for the Phalanx platform: http://www.raytheon.com/capabilities/products/searam/

        As for the old DF21 Aegis' RIM-161 (already deployed by USN and JMSDF) is capable to track and take down *hundreds* of incoming Chinese/Russian/etc ICBMs (and no enemy airplanes will fly anywhere near to any USN carrier strike group in combat, I guarantee that.)

        1. Vladimir Plouzhnikov

          Re: Because thats what sea life wants!

          "take down *hundreds* of incoming Chinese/Russian/etc ICBMs"

          They would say so, wouldn't they? Especially to the Poles, to whom they want to flog their missile defence systems, no?

          "Hey, dude, quick, see those scary Russians? They're gonna get ya! But you've lucked out here dude - I have just the right thing for ya here!"

          What can I say? - caveat emptor! :-)

          1. Levente Szileszky

            Re: Because thats what sea life wants!

            "They would say so, wouldn't they? Especially to the Poles, to whom they want to flog their missile defence systems, no?"

            Quite the opposite - the Poles are (understandably) desperate to get them for years now. US was always vary of installing such powerful systems, even if it's a clearly defense-only one, so close to the Russians. NATO simply did not want to give Putin an excuse to ignore the NATO-Russia Founding Act of 1997, even despite it never contained any provision that would put an *actual* limit on NATO deployment options - although Yeltsin was often claiming of putting "an obligation not to deploy NATO combat forces on a permanent basis near Russia"... despite all this NATO always kept the Russian beliefs and sensitivity in mind...

            ...and yet it was actually Putin who just flushed it down the toilet, starting with its *actual* signed article about the inviolability of sovereign borders in Europe, as it's clearly spelled out in Section I:

            "I. Principles

            In implementing the provisions in this Act, NATO and Russia will observe in good faith their obligations under international law and international instruments, including the obligations of the United Nations Charter and the provisions of the Universal Declaration on Human Rights as well as their commitments under the Helsinki Final Act and subsequent OSCE documents, including the Charter of Paris and the documents adopted at the Lisbon OSCE Summit.

            To achieve the aims of this Act, NATO and Russia will base their relations on a shared commitment to the following principles:

            development, on the basis of transparency, of a strong, stable, enduring and equal partnership and of cooperation to strengthen security and stability in the Euro-Atlantic area;

            acknowledgement of the vital role that democracy, political pluralism, the rule of law, and respect for human rights and civil liberties and the development of free market economies play in the development of common prosperity and comprehensive security;

            refraining from the threat or use of force against each other as well as against any other state, its sovereignty, territorial integrity or political independence in any manner inconsistent with the United Nations Charter and with the Declaration of Principles Guiding Relations Between Participating States contained in the Helsinki Final Act;

            respect for sovereignty, independence and territorial integrity of all states and their inherent right to choose the means to ensure their own security, the inviolability of borders and peoples' right of self-determination as enshrined in the Helsinki Final Act and other OSCE documents;

            (...)"

            And so on and so forth. Read it in its entirety here: http://www.nato.int/cps/en/natolive/official_texts_25468.htm

            Well, as we just learned not only given words do not mean anything but even signed, bounding agreements mean nothing to this bewildered, sneaky, spineless ex-KGB attack dog who runs Russia nowadays... too bad, Russians once again heading to the sewage tank of history, thanks to this mini-tzar and his ilks running amok in their neighborhood.

        2. Aitor 1 Silver badge

          Re: Because thats what sea life wants!

          Talk is cheap.

          Please provide a link for a radar than can track AND attack (lock) hundreds of high speed targets.

          There are NONE.

          Therefore, if you can't track and lock on them, exactly how are you going to intercept them?

  3. Winkypop Silver badge
    Alert

    Whales

    Because whales!

    1. Destroy All Monsters Silver badge

      Re: Whales

      They will be shredded in this thing's wake.

      1. I ain't Spartacus Gold badge
        Devil

        Re: Whales

        They will be shredded in this thing's wake.

        The next area for research is how to fit sufficient pancakes and hoisin sauce in the submarine, in order to deal with the shredded whale problem...

      2. Jack of Shadows Silver badge
        WTF?

        Re: Whales

        We, my ship, accidentally goosed a whale with one our rocket delivered anti-submarine torpedoes. It was NOT amused.

      3. lurker

        Re: Whales

        Given that aircraft can be downed easily enough by geese, I suspect collision with a whale will result in both the whale and the sub getting 'shredded'.

  4. DerekCurrie
    Angel

    And of course: To hell with the ocean environment

    This is just more irresponsible clown science that takes NO responsibility for its consequences. We're going to hear a lot about bozo science in the coming years. This example of Short Term Thinking, Long Term Disaster has to be an historical marker for a clear beginning of The Era Of Bad Science, what I also call The Age Of Trivia.

    Or to put it another way: We have issues of human and planetary survival at hand. So let's ruin the oceans some more, yahoo. Gawd, we can be stupid, we self-named Homo sapiens sapiens.

    1. Vladimir Plouzhnikov

      Re: And of course: To hell with the ocean environment

      "We have issues of human and planetary survival at hand."

      Yeah, that's why we want more scientific advances, not fewer, no?

    2. Marketing Hack Silver badge
      Go

      Re: And of course: To hell with the ocean environment

      It's OK DerekCurrie. Should we kill the oceans, there's always Soylent Green!

    3. Steve Brooks

      Re: And of course: To hell with the ocean environment

      "We're going to hear a lot about bozo science in the coming years. This example of Short Term Thinking, Long Term Disaster has to be an historical marker for a clear beginning of The Era Of Bad Science, what I also call The Age Of Trivia."

      Actually no, electricity started off as an essentially useless intellectual curiosity and nothing more, if someone had jumped up then and demanded we end all research into what was essentially a useless phenomena where would we be today? Pure research, the basic stuff, should have no thought to the end uses of its subject, however because most governments these days have now decided that research should only be conducted into areas where there is demonstrable financial return scientists are having to resort to ridiculous suggestions to continue to receive funding.

      For instance supercavitation in water may have no foreseeable useful function, but it may lead to way to reduce friction and drag in other media, air for instance, but unless we do the basic research we will never know where anything will lead.

    4. J__M__M

      Re: And of course: To hell with the ocean environment

      You say that like they can actually do this.

  5. Eddy Ito Silver badge

    Bovine

    feces!

    Hard money says they are talking "supersonic" relative to sonic velocities within the produced cavity not sonic water velocities. The whole point of making it cavitate is to provide a region of reduced friction which also conveniently supplies a region of reduced sonic velocity. Technically it may be supersonic in the cavity, but in water... not so much, hence I pitch a gigantic cow patty into the mix.

    Anyone want to work out the power equation for supersonic velocities underwater? Nah, me either.

    1. Cliff

      Re: Bovine

      Yep speed of sound in water > speed of sound in nice spongy air!

    2. James Micallef Silver badge

      Re: Bovine

      Getting anything to travel at the speed of sound though air (over 300 m/s) underwater would be a massive technological achievement. I wouldn't sniff at it just because they aren't going at the speed of sound through water.

      Besides, breaking the sound barrier underwater might not be desirable, sonic booms underwater could cause all sorts of havoc

      1. Vladimir Plouzhnikov

        Re: Bovine

        It doesn't move relative to the cavity. When they talk about supersonic they really do mean supersonic in water. This is basically a marine warp drive.

        1. Anonymous Coward
          Anonymous Coward

          Re: Bovine

          Not warp drive, that refers to taking a shortcut through normal space by warping it so that distant regions are proximal. Think "portable wormhole." this is more akin to a police car speeding through traffic using its siren to clear a path.

  6. GitMeMyShootinIrons

    colour me cynical...

    This is nothing to do with supersonic underwater freight or passenger transport - this is a weapons project.

    The Chinese navy have been pursuing ways to crack American carrier groups for a good few years to stop any intervention in a Taiwan crisis.

    They already have airborne tech (ballistic and cruise) either in development or service, but these have or can be countered with existing technology.

    What better than a standoff underwater supersonic heavy weapon? Place your sub say a hundred miles away and take pot shots with weapons that have practically no counter at the moment at ships that move massively slower - even a screen of sacrificial escorts wouldn't do much good as they are unlikely to be able to move fast enough to intercept.

    1. Charles Manning

      Why use the military?

      Why would China want to use the military to whack USA?

      They can just sit back and watch USA destroy itself financially. Much easier than getting that messy red stuff all over you!

      Anyway, it seems the Chinese have been able to get where they want for 7 years:

      http://www.dailymail.co.uk/news/article-492804/The-uninvited-guest-Chinese-sub-pops-middle-U-S-Navy-exercise-leaving-military-chiefs-red-faced.html

      1. Peter2 Silver badge

        Re: Why use the military?

        Exactly. It's easier and cheaper to get the US to scrap their ships because then they won't be replaced. They would be if they were sunk.

        In all fairness, the chinese subs aren't fantastic. The problem is that the US has a total lack of effective ASW capability which is routinely demonstrated and exploited by all of their allies in exercises. The root cause of that is that in the cold war the NATO warplan had the Royal Navy tasked with ASW where as the US navy was tasked with dealing with floaty stuff.

        What is odd is that the US simply doesn't rectify their embarrassing lack of effective ASW capability by buying some decent equipment from their allies.

      2. John Smith 19 Gold badge
        Unhappy

        Re: Why use the military?

        "They can just sit back and watch USA destroy itself financially. Much easier than getting that messy red stuff all over you!"

        Destroy itself?

        Who do you think owns most of the US governments debt, and thereby picks up the US's bills?

        The only reason the US can go on running around playing "Team America" is because Beijing holds their IOU's.

        Something the US collective simply can't cope with thinking about.

        1. Charles 9 Silver badge

          Re: Why use the military?

          "Who do you think owns most of the US governments debt, and thereby picks up the US's bills?"

          Its own citizens, if you care to check the actual books. Most bonds and treasury notes stay in the US. China does hold some US debt, but it's not a very sizable portion. It's one reason the US's sovereign debt isn't considered as dangerous as others: because most of it is held domestically.

          1. Guido Brunetti
            Flame

            Re: Why use the military?

            The single largest holder of official federal U.S. debt is the Federal Reserve Bank - a private institution with strong ties to "old money", followed by China, Japan and Brazil.

            Right now, China and the U.S. depend on each other, both economically and financially. But the Chinese work on both fronts to make these ties severable. And they pour lots of money in military technology to actually survive the eventual severance and become the next superpower.

          2. Irony Deficient

            US government debt

            Charles 9, monthly summaries of “the actual books” can be found here (for a list of holdings by country) and here (for a categorized breakdown). Thus, at the end of June 2014, foreign holders had 6.01 T$ of the 12.57 T$ total US public debt (47.8% of the total), of which China’s share was 1.27 T$ (10.1% of the total). Thus, 52.2% of US public debt was held domestically at the end of June; a majority of it, but not most of it.

          3. Charles Manning

            Re: Why use the military?

            Yes, the US National debt is mostly owned by its own citizens.... $10T out of $17T.

            However,...

            * only a paltry $7T is owed to foreigners, of which $4.5T is to China.

            * The citizens are themselves in a hole greater than what Ucle Sam owes them. Sammy owes them $10T, but the citizenry owe $17T in private debt. Thus the citizens themsleves are in no position to dig a bit deeper.

            * And then Sammy has a whole bunch of unfunded liabilities (eg. social security) which it owes (ie has promised) but has not yet had to pay, so don't yet show up as debt. That's $118T...

            All in all, China could tear up their note and it wouldn't make any difference to the trajectory US is on. Any wonder that the Chinese don't want to trade in USD any more -even if they have a pile $5T high!

      3. Mark 85 Silver badge

        Re: Why use the military?

        I think you might be close to the truth. Russia collapsed because of the costs involved in the Cold War and Ronnie Raygun upped the ante to push them over the edge. Might this not be a similar philosophy? A few successful tests and our (the USA) Defense Department will pissing all over itself while the Congress tosses unlimited funds at them (the DoD).

        Given the education available in the US, those who fail to remember history will repeat it. And since history isn't taught in any kind of depth or context...

      4. uncle sjohie
        Thumb Up

        Re: Why use the military?

        And that's not the first time, the Dutch submarine Walrus did the same in 1999 in an exercise, They "sank" the carrier USS Theodore Roosevelt, an SSN (USS Boise SSN-764) and a couple of destroyers and frigates for good measure. The commentorative T-shirts are still worn with pride..http://www.dutchsubmarines.com/boats/images/submarines/boat_walrus2_tshirt.jpg

    2. Phil O'Sophical Silver badge

      Re: colour me cynical...

      unlikely to be able to move fast enough to intercept.

      Would they need to intercept? Just create a big enough underwater shockwave to collapse the cavitation bubble, and the torpedos would self-destruct as they hit a wall of water at speed.

      A small battlefield nuke at 20 fathoms might be sufficient...

      1. Havin_it

        Re: colour me cynical...

        As many times as I hear the phrase "battlefield nuke" it still sounds wrong. "Battlefield" suggests a place where (conventional) battle is already underway; chucking a nuke into that seems a bit unsportsmanlike somehow. Not compared to randomly dropping one on civvies I guess, but stil...

        1. Greggles

          Re: colour me cynical...

          And is a nuke really necessary? Wouldn’t a couple of well aimed depth charges filled with Dawn dish soap work just as well?

      2. Eltonga

        Re: colour me cynical...

        Just create a big enough underwater shockwave to collapse the cavitation bubble, and the torpedos would self-destruct as they hit a wall of water at speed.

        A small battlefield nuke at 20 fathoms might be sufficient...

        I think that even the good 'ole depth charge can take care of that.

    3. Anonymous Coward
      Anonymous Coward

      Re: colour me cynical...

      "The Chinese navy have been pursuing ways to crack American carrier groups for a good few years to stop any intervention in a Taiwan crisis."

      And being able to pop their subs up undetected right in the middle of the carrier group isn't enough?

      In reality I can't see the USA risking a fight with China over Taiwan.... (where is the oil?)

      The UK certainly would not get involved (China is funding new nuclear power stations, and is a very good trading partner)

    4. Daggerchild Silver badge

      Re: colour me cynical...

      I've seen this tech before, in the context of US torpedos, so if it's weaponisable it's already been done. I don't think the torpedo tech even bothered with air - just the impact shock of the headshape was enough to form the void to travel in.

      On the other hand, since the US hasn't been crowing about it, the tech may be about as trustworthy as those hypervelocity ramjet things that keep disintegrating on them.

      Also, I suspect this stuff would lose an argument with the first decent-sized fish it met :-)

      1. Eltonga
        Paris Hilton

        Re: colour me cynical...

        Also, I suspect this stuff would lose an argument with the first decent-sized fish it met :-)

        We are going to lose the last reasonably sized tuna fishes to this end!!!

        What would be of the tuna sashimi market!!!???

  7. Ossi

    Something doesn't add up here

    The membrane coating that wears away bit doesn't seem to add up. Since the vessel is using it to steer, what happens when it wears away? This sounds like a one-shot device like, say, a torpedo, not a submarine.

    1. BlueGreen

      Re: Something doesn't add up here @Ossi

      > This sounds like [...] like, say, a torpedo

      You know old bean, I almost think you had it just then.

    2. Peter Simpson 1
      Mushroom

      Re: Something doesn't add up here

      Isn't this thing going to leave a trail of bubbles?

  8. Anonymous Coward
    Anonymous Coward

    Pointless idea

    There's too much junk in the oceans of the world. Hit a piece of flotsam at any kind of speed and the craft is going to explode most impressively. Not a very appealing prospect for fare paying passengers.

    As a weapon its not going to be very successful either, unless you put a nuke on the front of it. It won't be able to guide itself, there'd be too much noise generated by its own speed. It won't be possible to guide it from the firing platform either; how would you pay out the guide wire at that speed without it snapping, and then how would you stop it burning up in the rocket exhaust? I don't think the Russians managed to do that with their Skvahl.

    So it'd very much be a fire and forget and hope kind of thing requiring a nuke to be sure of causing damage. Firing for close range would improve the odds of a hit, but then you might just as well use something more conventional if you can get that close and save all that development cash.

    Sounds more like some researcher somewhere is getting away with spending government funding without the pay masters having any idea as to the unlikely chance of this being in any way successful.

    1. I ain't Spartacus Gold badge

      Re: Pointless idea

      Nuking carrier groups has been a part of military planning since at least the 1960s. Tactical nukes were designed for relatively small, high-value targets. Whether they be Warsaw Pact bridgeheads over German rivers, NATO carrier groups, airbases or rail junctions.

      Admittedly nuking a significant target and destroying $100bn worth of enemy shiny-shiny, along with killing say 10,000 of their personnel, is not likely to end well. Particularly if that nation is equipped with strategic nuclear weapons, not to mention tactical ones of its own.

      Then again, by the 70s, most NATO planning for the Central European front pretty much admitted that it was either lose, or resort to nuking the Soviet spearheads within just a few days of the war starting. So part of the plan was that you act as if you'd go nuclear in your normal battle-planning, thus the other side knew that even starting a purely conventional war was a big step in nuclear escalation.

      This may be China's tactic with the US? We might admit that our navy and airforce can't defeat yours, but we think this conflict is so important that we'll simply ensure we win it by going tactical nuclear, and inflict unacceptable casualties on you. Then your choice will be nuclear escalation or humiliating surrender. As neither of those are appealing, you'd better either develop a counter to getting your carrier groups nuked, or keep your nose out.

      As with Russia, it's hard to know what the Chinese think their own national interest is. They're involved in as many border disputes as Russia, but the Russian ones are mostly about nationalism and ex-Soviet Russian populations abroad. Whereas the Chinese ones seem to mostly be about off-shore oil and gas. I don't think they're interested in their various land-border disputes, like they were last century. Obviously the exception here is Taiwan. On the other hand, both countries' economies are massively reliant on global markets and international trade, so even creating international tension costs them money and the economic stablity that they require to keep their populations happy and avoid potentially getting chucked out of power.

  9. Holtsmark
    FAIL

    Supercavitation

    The research into supercavitation is actually nothing new, and this is something the article should not have ignored.

    As stated in posts above, the obvious application for this tech is not transportation, but torpedoes.

    The russian submarine "Kursk" is rumored to have sunk due to a failed test of a supercavitation torpedo. This is supposedly why they were very keen on the damaged torpedo-room not being raised, resulting in the sub having to be cut in two before the rear part could be raised. Although I know about more nations doing research into supercavitating rockets, the Russians appear to be at the leading edge of this tech. Their targets will most likely be the same as that of the chinese; US naval forces, especially carriers.

    1. ecofeco Silver badge

      Re: Supercavitation

      Yep.

  10. Tom 64

    I don't get it

    If you want to go supersonic, why not just do it through the air where you don't have to bother with engineering away the water?

    The only application must be military, so the Chinese can deliver a nuke to San Fran bay totally undetected or so. But surely there are easier and less expensive ways to threaten your enemies.

    1. Destroy All Monsters Silver badge

      Re: I don't get it

      Delivering nukes undetected is not the goal of nukes though.

    2. Voland's right hand Silver badge

      Re: I don't get it

      Simple reason: Gatling guns, close-up interceptor defences, etc. It is a constant arms race. Presently, it looks like supersonic, sea skimming missiles like P700 and Sunburn have a slight advantage. That is probably short lived as anti-missile defences will be upgraded to deal with these. In any case - the situation there is a close call.

      Compared to these a sufficiently _MANEUVERABLE_ long range (20 miles+) supercavitating torpedo is nearly impossible to intercept. You simply cannot build an interceptor which will pull the required Gs and speed under water to get itself into position to deal with it. So your only option is to saturate its entire approach sector with depth charges across the whole range of depths and pray. You also have to do it sufficiently far out just in case someone has put a 0.5Mt warhead on that bugger. That option by is presently unavailable - there is no fleet defence ship or aircraft capable of launching the required salvo size to the required distance (you are looking at something like the BM21 or similar missile launchers (20km+ range) with proximity/depth charge warheads using some guidance/at-depth loitering and most likely multiple of those per carrier group.

    3. BlueGreen

      Re: I don't get it @Tom 64

      > If you want to go supersonic, why not just do it through the air where you don't have to bother with engineering away the water?

      Perfect question, and one that has bothered me since I heard about shkval in a new scientist article on supercavitation. I thought it so frigging absurd assumed initially it was a windup.

      Here's why: shkval goes at 200 knots, which is about 100 metres a second. Water is 1 tonne per cubic metre (roughly), and if the diameter of the cavity is say 1 metre (shkval's diameter is 21 inches per wiki, so that's not unreasonable) then you're displacing about *80 tonnes of water a second* (assuming I dun skoolboy rithmetic ok). That's a huge energy expenditure unless you can somehow regain some of that - stuffed if I can see how, maybe the collapse behind somehow pushes the bubble forwards, but I don't see how that can work.

      Minor note, wiki does not say shkval emitted gas from its nose, only "the torpedo is, in effect, flying in a gas bubble created by outward deflection of water by its specially shaped nose cone and the expansion of gases from its engine". Hard to see how the nose can take that much pressure and friction.

      +++

      Totally tangential question. It turns out shkval means 'squall' in english. I've noticed a lot of russian words do seem very closely related to english ones and I've no idea why, it's almost as if russian and english are cognates but to my knowledge they're not. Any thoughts?

      1. Nigel 11

        Tangential @BlueGreen

        I've noticed a lot of russian words do seem very closely related to english ones and I've no idea why, it's almost as if russian and english are cognates but to my knowledge they're not.

        English and Russian are both members of the Indo-European tree of languages. The common roots were several milennia back, but even so it's a lot more commonality than English and Chinese (or English and that linguists' puzzle, Basque).

        Also, English has a huge vocabulary compared to most languages. It arose from a merger of Anglo-Saxon and Norman French ( themselves both hybrids). Since then, rather than jettisoning redundant words, it's been shuffling them to create subtle differences of meaning. So if there is a common Indo-European root for a Russian word, there's probably twice the chance that you'll recognise it in English (compared to, say, German or Spanish)

        1. awol

          Re: Tangential @BlueGreen

          Also French was the last language of the royal court before the revolution (IIRC) and so there are man words in russian that are simply transliterations of french words and so when looked at from an english tongue (;) seem very english (pectopah anyone?).

      2. Vladimir Plouzhnikov

        Re: I don't get it @Tom 64

        "Perfect question, and one that has bothered me since I heard about shkval in a new scientist article on supercavitation. I thought it so frigging absurd assumed initially it was a windup."

        Shkval was designed for launch from submerged submarines, not from the surface vessels. Its primary role was to intercept enemy's torpedoes. Nuclear armed version was to penetrate the ASW screen of a carrier group. Makes sense in both cases.

        "you're displacing about *80 tonnes of water a second*"

        In supercavitation you are not displacing the water physically - you are evapourating and recondensing it behind you. Apparently, it takes less energy for that than shoving it away.

        "It turns out shkval means 'squall' in english. I've noticed a lot of russian words do seem very closely related to english ones and I've no idea why"

        In this case it is quite simple - when the Russian Navy was being developed by Peter the Great, he sent the future officers in great numbers for training abroad, in particular, to Britain - to train with the Royal Navy. So a lot of Russian naval terms have been borrowed from the British and Dutch terminology.

        1. BlueGreen

          Re: I don't get it @Tom 64

          > Shkval was designed for launch from submerged submarines, not from the surface vessels.

          In the context of shkval's energy use, I can't see the relevance.

          > In supercavitation you are not displacing the water physically - you are evapourating and recondensing it behind you

          80 tonnes of water vapourised per second? Given the high quality of your other posts I'm amazed you'd suggest this.

          > In this case it is quite simple ...

          Oh, interesting! Thanks for this, and to @Nigel 11

          1. Vladimir Plouzhnikov

            Re: I don't get it @Tom 64

            "In the context of shkval's energy use, I can't see the relevance."

            Wasn't the original question - why not shoot through the air instead of through the water? When you are in a sub at depth, this is simply not an option.

            "80 tonnes of water vapourised per second?"

            But it's cavitation, not boiling. You don't need to heat the water to 100C or higher, you need to drop the local water pressure below the vapour pressure. Cavitation conditions are defined by cavitation number (the lower the better). You can lower it by limiting depth, by increasing the cavity pressure (by diverting some exhaust from the rocket engine into it) and by increasing velocity (its inversely proportional to velocity squared). Then, I'm not sure it's the entire hull displacement volume of water that is being vapourised - only the volume of the cavity minus the volume of the vessel.

            It appears that for very low cavitation numbers (high speeds, in the region of 1,000 m/s) and for certain hull shapes and aspect ratios the volumetric drag falls dramatically (orders of magnitude), while at higher cavitation numbers (v=300m/s) same hull volume and aspect ratio the drag may only be 50% lower than for non-separating flow.

            There are additional problems, of course, such as the loss of buoyancy etc but the whole thing is fairly fascinating...

            1. Steven Jones

              Re: I don't get it @Tom 64

              Supercavitation does not vapourise and recondense all the liquid in the path of the "missile", just a relatively small proportion. The process is used to generate the bubble in which the object travels and massively reduces surface friction.

              Most of the water will be displaced, but due to the very low friction the energy used in pushing the water aside will (mostly) be returned when it collapses back together after the "missile" bubble has passed.

              1. BlueGreen

                Re: I don't get it @Tom 64

                > Supercavitation does not vapourise and recondense all the liquid in the path of the "missile", just a relatively small proportion.

                See my calculations. A hole in the water (which is often descibed as 'incompressible') a metre or so across and 100 metres long has to be created every second of shkval's movement. That's the bottom line and however you cut it, that's seems to be need a *lot* of energy.

                > but due to the very low friction the energy used in pushing the water aside will (mostly) be returned when it collapses back together after the "missile" bubble has passed

                Really? Returned where? If to the missile's momentum, then how?

                1. Vladimir Plouzhnikov

                  Re: I don't get it @Tom 64

                  "That's the bottom line and however you cut it, that's seems to be need a *lot* of energy."

                  But, surely, the point is that it needs a lot *less* energy for going that fast than a non-supercavitating torpedo would.

                  "Returned where? If to the missile's momentum, then how?"

                  Not to the missile, into the surrounding water, as heat and acoustic energy mostly.

    4. kmac499

      Re: I don't get it

      Why build a supersonic sub sea missile when Maersk will deliver to SF or LA from Shanghai in a neat 40 foot box, far cheaper...?

  11. jake Silver badge

    Daft concept.

    I was a test driver/pilot/throttle-man/mechanic for Dale Arneson when he was developing his surface piercing drives a third of a century ago. This kind of technology is VERY fast (see off-shore racing), but to get a vehicle supersonic underwater for more than a few yards/meters? Laughable, at best.

    1. Benjol

      Re: Daft concept.

      I don't get it. Didn't you previously say you were the pope at that time?

      1. Anonymous Coward
        Anonymous Coward

        Re: Daft concept.

        What makes you think he couldn't be pope and master marine mechanic at the same time? This is jake we're talking about. He's amazing.

    2. Anonymous Coward
      Anonymous Coward

      Re: Daft concept.

      Dale Arneson eh. Not Howard Arneson, which was his actual name?

      1. Graham Marsden
        Facepalm

        @AC - Re: Daft concept.

        > Not Howard Arneson, which was his actual name?

        Ah, but only jake got to call him Dale!

    3. Anonymous Coward
      Anonymous Coward

      Re: Daft concept.

      76. Master Marine Mechanic

      1. jake Silver badge

        @detractors: Re: Daft concept.

        OMC Master Mechanic, actually, and CDM.

        Dale is Dale.

        Me the Pope? That's even stupider than the idiot who proclaimed that I worked on the Apollo Project. Honestly, the mind boggles.

        As for the serial down-voter ... Try to get a life of your own instead of going through my back-log and down-voting me. It's been tried before, but I don't back down from attempted toothless bullying. "Thumbs" in this forum are a useless measurement ... and in fact says more about you than about me. (Seriously, how much time out of your life did you waste on that?) But whatever, if it turns you on, carry on :-)

        I note that not one of you lot addressed my actual point, that being "but to get a vehicle supersonic underwater for more than a few yards/meters? Laughable, at best."

        1. Anonymous Coward
          Anonymous Coward

          detractors...

          .. what Jamaican farmers use to plough de fields

  12. Nick Ryan Silver badge

    Military-ish tech research tends to pay off in the long term, and the long term is something the Chinese (government) tends to look at rather than four year cyclic self-destructive short term goals. It'a also important that the Chinese maintain enough military capability to ensure that they have an adequate military presence, but as noted about their main advantages are financial and production capabilities.

    While this application has obvious potential for warhead delivery the spin offs are likely to benefit all manner of technology fields where fluids are involved - including pipes, gas/liquid delivery systems, more efficient boats and so on.

  13. Pen-y-gors Silver badge

    The wake?

    Methinks something travelling underwater at a lot of mph will leave a fairly obvious surface wake to trace.

    1. Comedy of Errors

      Re: The wake?

      Not just a wake, presumably there will be a trail of bubbles pointing like an arrow to your final location, plus a great deal of underwater noise from bubbles and jet engines. All things you don't want in a submarine.

      1. Nigel 11

        Re: The wake?

        Except it's going so darned fast, you don't have the time to do anything about it! Compare a ground-to-air missile which leaves a very obvious exhaust trail, but that doesn't much help what it's aimed at.

        (More use as a torpedo than a submarine, though).

        1. Grikath Silver badge

          Re: The wake?

          That's the point isn't it? For all current detection purposes, a sub using this will be so noisy you can pick it up 100's of miles away. If it ever gets built it would be more of a "Warning! We cracked the secret of this little trick..." type of grandstanding as opposed to having any actual military tactical value.

          1. Anonymous Coward
            Anonymous Coward

            Re: The wake?

            Thing is, though, it's only noisy once you launch it. If you can get in decently close, say a few miles, and let loose with a few of them, you cut the closing time to a few minutes at most. A torpedo going at 240 knots would cover a nautical mile in just 15 seconds. Plus it's completely underwater and would have momentum and inertia due to its high velocity. It's the underwater version of a ballistic projectile in the drop stage; physics is on its side. What kinds of countermeasures could you use that would be both effective and capable of deploying in number in what little time you may have to react?

  14. Graham Marsden
    Coat

    Can I just say....

    Standby to launch SkyDiver!

    1. John Smith 19 Gold badge
      Coat

      Re: Can I just say....

      "Standby to launch SkyDiver!"

      Strictly speaking...

      Launch Sting Missiles.

      Who knew?

  15. Rol Silver badge

    Drones?

    A fleet can deploy drone outriders to detect incoming torpedoes and counter with an inner ring of drones equipped with, short range, dart like torpedoes, designed to intercept at high speed.

    I anticipate the drones would be small and torpedo looking, with a propulsion system capable of fleet speeds. Deployed from the air some twenty miles from the fleet, they should give any commander a sense of ease.

    Alternatively the drones could be nothing more than seafaring copters. Again, dropped into location from a seeding drone, they float along the detection perimeter listening for their quarry. Once the fleet has passed beyond their operational zone they leapfrog to a forward point or return to a support ship to be refuelled and redeployed.

    Or...Just drop floating hydrophones from a drone and recover them with the same drone using the ultra fantastic hook and eye tech.

  16. privatedick

    physics violation?

    Seems to me the gas ejection system must push the water out of the way, which will create frontal area resistance, which could be tons of resistance.

  17. Uffish

    Star Wars (The Reagan version).

    Sounds just like the American wheeze to destabilize Soviet Russia, same hype, same 'insouciance' as to whether it can ever work; the hype and the workout for the scientific/industrial team is well worth the money, and it will impress the uncritical masses too. Overall, a (small) win for China.

    1. Graham Marsden

      @uffish - Re: Star Wars (The Reagan version).

      > Sounds just like the American wheeze to destabilize Soviet Russia, same hype...

      ITYM "Same Ret-Con", claiming after the event that it was all a clever and sneaky plan (and not a whole load of money pi$$ed away on pie-in-the-sky unworkable boondoggles...)

      1. Uffish

        Re: whole load of money pi$$ed away

        I stand corrected. Make that a small win for America.

  18. JeffyPoooh Silver badge
    Pint

    Define "air"

    "...to generate its own air bubble."

    Where does the "air" come from? Is it "air", but '...not as we know it Jim.' ?

    What keeps it level? It's a big heavy machine poised in an "air" bubble. So what keeps the big heavy rump from falling down?

    How fast does the water move sideways to get out of the way? How does that sideways velocity compare to the speed of sound (compressibility) in water?

    1. Chris G Silver badge

      Re: Define "air"

      In general in things like hydraulics, cavitation is not really an 'air' bubble, it's a cavity, hence the name, a space in the liquid that is most simply described as a bubble. when pressure drops below a certain point in liquids they will tend to vaporise a bit in an attempt to equalise the imbalance or can produce a low pressure cavity due to shock waves which in turn produce their own shock waves as they collapse rapidly, both not good in most cases. On a badly designed power boat propellor for example, it is constantly moving forward and lumps, bumps or pits on its surfaces can create shock waves that will result in cavitation and in this case drag reducing its efficiency.

      I think from the article the head of the torpedoe or sub is moving forwards so rapidly it is creating a pressure shock wave that is effectively bouncing the water in front of it, away thereby creating a low friction cavity for it to move into. what I am not clear about is how the continuing shockwave maintains a cavity instead of it fluctuating or periodicly cancelling itself out.

  19. Anonymous Coward
    Anonymous Coward

    White elephants or paper tigers?

    "The Chinese navy have been pursuing ways to crack American carrier groups for a good few years to stop any intervention in a Taiwan crisis".

    The American carriers have been expensive white elephants for at least 50 years. Relative to the Chinese, perhaps "paper tigers" would be a better phrase. In 1939, most politicians and admirals thought battleships were still the bee's knees. By 1945, the brand-new Iowa class - by far the best battleships ever built - were essentially obsolete, and the only duty that could be given them was providing AA fire for the carriers. However the carriers themselves, instrumental in winning WW2, became extremely vulnerable to missiles and torpedoes.

    The only reason they are still parading proudly around the seas - for all the world like HMS Hood in the 1930s - is that no one has had a big enough war with the USA to take them out. (Also, they are handy for bullying nations that have no air defences or submarines worth speaking of).

    Besides, it's smarter for the Chinese, Russians, Iranians, etc. to let the Americans go on shovelling huge sums of money into carriers, ridiculously expensive jets to fly off from them, and escort forces than to demonstrate that they are obsolete, and have the USA start building ships that would actually be useful in a modern war.

    1. DocJames
      Stop

      Re: White elephants or paper tigers?

      By 1945, the brand-new Iowa class - by far the best battleships ever built - were essentially obsolete

      In 1941, the Japanese demonstrated that battleships were essentially obsolete in wars between nation states powerful enough to own carriers. You should look it up some time.

    2. Rick Brasche

      Re: White elephants or paper tigers?

      I guessed you missed the tsunami aid missions where one carrier was repeatedly able to handle more humanitarian aid (as well as power and water generation) than any infrastructure built for weeks.

      the whole deterrent factor, of how many dozens of tinpot dictators kept their tiny air forces on the ground because one carrier was projecting force in the region probably goes over your head too.

      If you're going to talk tactics, you need to think the big picture, where you're partially correct; But it is also smarter for the Chinese to get the Americans to shovel more money into *defending* their expensive hardware as well as just building it.

      the carrier is probably the only military vehicle that is worth it for its NON military use.

  20. JaitcH
    Go

    Big Market for this Technology in South America.

    This would really get the drugs market hopping. And the US DEA!

  21. JLV Silver badge
    Alert

    What could go wrong?

    Nifty research, don't get me wrong.

    But if the bubble collapses somehow, you end up hitting a brick wall in short order.

    Fine for a torpedo, but as a passenger, I'd be a tad worried.

  22. Ian Emery Silver badge
    Happy

    So does this mean...

    .... I can now order take out from my favourite Guangzhou Restaurants and expect it to still be hot when delivered to my UK home???

    1. Mark 85 Silver badge

      Re: So does this mean...

      Hmm.... no. That delivery will be by hypersonic rocket. You'll know it's there when you hear the sonic boom and the house next door is flattened.

      1. Vladimir Plouzhnikov

        Re: So does this mean...

        Correction: you will know it's there when the house next door is suddenly flattened and then you hear the sonic boom :-)

        1. Rick Brasche

          Re: So does this mean...

          if the food isn't good enough, your neighbors will know when you flatten your own house.

  23. zen1

    If it's not nuke powered, it's gotta be a bitch to refuel, or be almost cost prohibitive, at best.

    1. Eltonga
      Headmaster

      If it's not nuke powered, it's gotta be a bitch to refuel, or be almost cost prohibitive, at best.

      If it is nuke powered it will be no difference at all regarding to cost.

  24. Catweazle666

    Supercavitating torpedo technology...

    Anyone remember the Kursk?

    Lively stuff that hydrogen peroxide, especially in submarines.

  25. Javapapa

    Chinese takeout

    100 minutes is a little long to wait for Shanghai cuisine to be delivered to San Francisco.

    Unless "takeout" means delivering something hotter than Gen Tso's chicken.

  26. Curtis

    Someone's been reading John Ringo & Travis S Taylor...

    I wonder if they'll play "Final Countdown" through speakers to scare the whales away...

  27. Anonymous Coward
    Anonymous Coward

    remember the Kursk

    something blew the front end off a giant boomer, something non nuclear. Something with enough propellant to do the job.

    What else comes out the front torpedo tubes with enough propellant to do something like that? SRB's on a Shkval, where the supercavitating bubble failed to generate properly, might do something exactly like that.

    BTW, even the Iranians claimed to have this technology. Navy was looking at bullets that did this, as a minesweeper tool.

    Problem is, no one has yet figured out how to steer the thing. Straight line only pretty much.

  28. Marketing Hack Silver badge

    Does Ringo have a hole in his pocket?

    I think supercavitation could be possible for something torpedo-sized, but I am a bit dubious on a whole submarine. Unless this is just intended as a research project, I think its about as fanciful as the Beatles' submarine.

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