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Technology

Supercavitation: Ultrafast Underwater Weapons 152

Posted by michael from the never-hear-the-one-that-gets-you dept.
Peter Dyck writes: "According to this article, the world's major naval powers are developing the means to build entire arsenals of innovative underwater weapons and armadas of undersea watercraft able to operate at unprecedented speeds. This high-velocity capability - a kind of "warp drive" for water - is based on the physical phenomenon of supercavitation. The trick is to surround an object or vessel with a renewable envelope of gas so that the liquid wets very little of the body's surface, thereby drastically reducing the viscous drag." We've done a couple of articles about these weapons before, but Scientific American has good explanations and diagrams and some new information. If (when?) underwater guns actually come into use, it will change the entire nature of underwater warfare.
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Supercavitation: Ultrafast Underwater Weapons More

Supercavitation: Ultrafast Underwater Weapons

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  • Supercavitation (Score:1)

    by Anonymous Coward
    isn't that the right term for the Goatse man?

  • re-run (Score:1)

    by Anonymous Coward
    This wasn't new last time [slashdot.org] or the time before that [slashdot.org]

  • Re:What about Whales? (Score:2)

    by Anonymous Coward
    Radar Operator: Captain, captain...sound the alarm!!
    Captain: What is it man?! [captain glances down at radar screen] good GOD -- look at the size of it! [captain runs of quickly]

    Loudspeaker: [alarm siren sounds] Alarm, alarm, we have a troll, monstrous in size! Battlestations everyone, the flamewar is beginning in t-minus .004 secs!!!

  • Silly. Star Wars isn't about a viable defense system, it's about handing over boatloads of taxpayer money to companies that bribe the right (or should that be Right 8) politicians.

  • I don't know about whales, but I can attest to the fact that I can barely tolerate the fan noise in a typical x86 machine for very long, let alone the looping soundtracks in the games my kids play when they walk away from their computers without stopping the application. And I'm not very intelligent myself so I'd be sympathetic to marine life even if they weren't very intelligent either. The evidence for bottlenose dolphins, at least, seems to lean towards intellignece [earthtrust.org], though.
  • Given our capability to destroy other species on mass, which all other species lack, it would be well to say that we are the only species that need to worry.
    John
  • Really, the whole beaching thing, I think, is not a big deal. It happens, and a few dozen whales die from it each decade.

    What we really need to worry about is the mass slaughter of whales that has been going on for the past 200 years. Let's put that a bit higher on our priority scale, shall we?

  • This is a big problem for US (Score:3)

    by drix ( 4602 ) on Sunday May 06, 2001 @06:39PM (#242593) Homepage
    Supercavitation is really not anything new, however it spells big big trouble for the US military. I haven't read this article but I'm assuming it makes mention of the Russian "shkval" (squall) rocket torpedo, which can do an amazing 200mph underwater. If not, go look it up on Google. This thing is fscking sweet. Nothing in our arsenal comes even close to competing with this technology, and, as the post said, it will change the face of naval warfare. Defense analysts say the Russians are at least 20 years ahead of anyone else for supercavitation, and they're selling it to all their friends (China, etc.) I think this stands to really alter the strategic balance of naval powers. What good are our 11? 14? whatever---what good are our carrier groups when you've got torpedoes coming in as fast as an Indycar (faster!). Nothing. Nada. Kaput.

    --
  • Though there are great implications for what this could do outside of warfare, it is a little dissappointing that the most obvious and immediate uses of this technology will be used for war puposes. There are a whole slew of things this could be used for in the commercial sector.
  • As the AC said, you can't really prove something like this, but I'll back it up to some extent.

    A friend of mine was reading an old Celtic legend in class the other day. At the end of the legend, the hero becomes king and reigns over the land for a long, glorious era of peace. This peace lasted about five years. Nearly every political unit in the world was nearly constantly at war throughout history. Now, what do we have? Little brushfires that would have been considered to be, roughly, peace now are all that's there, and they draw attention from the major world powers which fall over each other to stop the horror. It's certainly a safe time to be alive as far as wars go.
  • My point isn't that the world is totally peaceful. My point is that it's been relatively more peaceful during the last fifty years than before. You'll notice there are two continents free from major conflict, and they have been for a long time. That's better than any other period of history right there.

    About your point about the huge war a little over fifty years ago: why in hell do you think I specified the past fifty years, instead of the past sixty?

    The peace at the end of the 19th century did not last 50 years.

    It is safer, nearly everywhere, than it was before. People are killing each other like crazy now, but they always have been, and it's happening a lot less today.

  • Re:We live in barbarian times (Score:4)

    by HeghmoH ( 13204 ) on Sunday May 06, 2001 @11:20AM (#242597) Homepage Journal
    Especially more recent history

    Bullshit. The past wasn't some happy place where people all got along, until people invented airplanes and poison gas and atomic bombs and ruined it all. The last fifty years have been the most peacful period in human history, and military budgets have always been funded even when other things couldn't be.
  • Well, think about what something like this, on a larger scale, would do for shipping and/or passenger travel.

  • I don't want to be on a submarine in the next big international pissing contest, someone is going to get fucked up. Supercav weapons can be launched from the surface as normal rockets and then go into supercav mode when they hit the water. This turns a Seahawk helicopter into a number one sub killer rather than a second or third tier theater weapon. Destroyers are going to go from minor picket ships back to line ships because they can equip and refuel Seahawks et al for sub killing. Weird, just like back in the old days.

  • If? When? (Score:3)

    by DES ( 13846 ) <des@des.no> on Sunday May 06, 2001 @09:38AM (#242600) Homepage

    There's no "if (when?)" about this. According to the SciAm article (the print version, at least - I haven't read the online version), the Soviet Union already had a supercavitating torpedo (codenamed "Shkval") in 1977. Apparently, Russia, strapped for cash as always, has been selling them off; France has reputedly acquired a few to bootstrap their supercavitation research programme.


    DES
    --

  • Re:won't totally change (Score:5)

    by DES ( 13846 ) <des@des.no> on Sunday May 06, 2001 @09:33AM (#242601) Homepage

    The supercavitating projectiles are still going to have a hard time changing course.

    A supercavitating torpedo or shell may be fast enough that a close-range opponent doesn't have time to dodge - even better, a supersonic weapon could hit your opponent before he heard it coming, since it would travel faster than both its own noise and a sonar return.

    Disregarding that situation, supercavitating weapons are still useful as "engagement breakers", i.e. weapons that, even if they do not hit the opponent, force the opponent to abandon a favorable attack position and cut loose any wire-guided torpedoes he may have launched.


    DES
    --

  • Geology Earthquakes and Natural Disasters (Score:3)

    by Hangtime ( 19526 ) on Sunday May 06, 2001 @01:56PM (#242602) Homepage
    Whales tend to live in deep waters preferring them to coastlines mainly because of the greater abundance of life to feed on the bottom. As to earthquakes and volcanoes underneath the ocean, earthquakes rarely if ever occur along spreading centers (plates that are moving apart) when looked at in the proportion of convergent and transform fault earthquakes. This is due to the plates moving away from one another not towards each other, so not much stress is involved. Second, volcanoes under the water are not clastic or viscous. In fact, underwater volcanoes are always basaltic meaning they have very little silicon oxide (about 50%). The silicon oxide contributes to the viscousness (resistance to flow) and why Mt. Saint Helens blew really high and really loud. Volcanoes underneath the water are not viscouses at all meaning that magma flows out readily, and cools quickly looking like a mushroom. Since their is no pressure built up by resistance to flow (Mount St. Helens) their is no tremendous release of pressure and therefore no BOOM. On a side note, these areas of divergent zones are home to some of the most interesting life in the sea and full of rich mineral deposits. Class dismissed.

    Hangtime

  • Re:What, no technical discussions? (Score:3)

    by WasterDave ( 20047 ) <davep.zedkep@com> on Sunday May 06, 2001 @09:23PM (#242603)
    Super cavitating weapons would travel faster than the speed of sound, so it cannot be detected sonically

    Nope. They're talking about 200 knots (approx) here, so sub speed of sound in air, let alone water.

    Dave
  • At first glance, I read:

    Ultrafast Underwear Weapons

    At I wondered what that had to do with geeks... as if anyone would attack a geek's underwear.

  • Supercavitation is really not anything new, however it spells big big trouble for the US military

    I doubt it very much. The US submarine doctrine has always been based on stealth: staying undetected (aka pretending to be a big hole in the middle of the ocean) is US subs' strong suit. I believe there is general consensus that staying-stealthy-while-detecting-the-other-guy capabilities of US Navy are noticeably better than those of the Russians.

    Nothing in our arsenal comes even close to competing with this technology, and, as the post said, it will change the face of naval warfare

    Maybe, maybe not. Keep in mind that supercavitating torpedos have a very, very big drawback -- they are not guided. They are basically a bullet -- you shoot it out and it goes in a straight line until it hits something or runs out of steam. This means they are useful only at very short ranges, and only if you have a very good idea where the enemy submarine is. Neither condition is usually true in submarine warfare.

    what good are our carrier groups when you've got torpedoes coming in as fast as an Indycar (faster!).

    Carrier groups have an anti-sub screen. Generally the large surface groups try not to get an enemy sub anywhere close to shoot off a torp, supercavitating or not. If a sub managed to get close enough to shoot, I doubt it would matter very much whether the torpedo is very fast.

    Besides, there are subs which are equipped with anti-ship cruise missiles. Cruise missles are even faster, can be launched from farther away, and can guide themselves. This is already an existing threat and it sounds more dangerous to me than supercavitating torps.

    Somehow I doubt the Navy will be holding a big discount sale of its carriers any time soon.

    Kaa
  • But seriously: water-warfare sounds like a 'relatively' good idea (if you forget that warfare sucks etc etc) as it minimises 'colateral damage' (i.e. innocent people getting hurt).

    You mean like the sinking of the Lusitania? [aol.com] In which 1,195 lives were lost? There are plenty of people-carrying vessels out there that are in danger at wartime.
  • Oooooh. Underwater warfare! We're so scared. What are you gonna' do, kill all our fish?

    Read the article again. The underwater missiles have the potential of scooting along underwater until they get to the coast, and then popping up and blowing away coastal cities, thus rendering any Star-Wars-style missile defense systems useless. Now, think about how just about every country has ships in the ocean that are permitted to come right up to our shoreline, and you'll realize that they don't even have to be that accurate in order to wipe out cities like DC, NY, LA, Miami, etc. Yes, you should be scared.

    Of course, most of this can already be done on a smaller/cheaper scale by smuggling nuclear weapons aboard container ships, but this allows for a more timely attack, I guess.
  • >The leading documented cause of death among >Right Whales is being struck by boats . . .

    where did you get your info from? There have been very sparse documentation of Right Whales at all, at least in the North Pacific. Their estimated world wide population is critically low, about 100-200(!) and i haven't heard of any Right Whale takes by boats. i am a marine biologist in Alaska. If you have seen one, send photos!
  • quote: when it was used on vehicles -- got great results in the indy 500 in the 1950's but never went into production because the engine had no crankshaft, no valves, no pistons, no transmission -- not much need for lubricants.
    are you blaming the world oil consortium (lubricants) on the suppression of gas turbine technology in cars? it probably had more to do with the fact that the engine and exhaust on gas turbine cars reached temperatures of 400-600 degrees!
  • you are right, i think boat strikes are overreported. there is more consistant data pertaining to fishing gear entanglements, especially pelagic trawl gear than propeller takes. These statistics don't just apply to right whales, although right whales seem to be a lot friendlier to boats than most whales (save the orca... just ask any fisherman!) which makes them more vulnerable to being hit.

    Going back to your original comment about whales being hit by supercavitating projectiles, i'm not sure if they would be at any higher risk than being hit by a conventional torpedo. I haven't heard of a hostile submarine encounter that involved incidental cetacean mortality, but you might have a link to that too! (:

    one large concern is the amount of noise that supercavitation technology radiates is much higher than conventional means of propulsion. an underwater "sonic boom" could be very detrimental to marine life (especially cetaceans), and commercial use of supercavitation on shipping lanes could have a devestating effect on migration patterns, habitat, etc..
  • The Right Whale was named by whalers because it was the 'Right' whale to harpoon (good huntin' I believe).
    it's even worse than that. they were the "right" whale to hunt because they were so friendly to boats. they had large amounts of oil in their upper bodies (especially the head region) which made it easy to extract product, and the whale even floated dorsal side up when it was dead which facilitated processing!

    like the captain mentioned above, i believe the reports of right whale collisions with boats are overreported compared to other types of right whale fatalities partly because of the NOAA's mandatory requirement that all vessels report these takes. Given that there are about 350 in the north atlantic and even fewer in the pacific, right whale takes, whether it be gear entanglements or collisions, do not happen everyday!

    the data on fishing gear entanglements are more consistant (at least for the north pacific fishery) and they are reported by fishery biologists, not boatowners.

    Incidentally, collisions with boats and gear entanglements have been documented with all types of cetaceans, not just right whales, which are given special attention becuase they fall under the "endangered" classification of the Endangered Species Act.

  • Also, US Navy sonar will most certainly detect something appraching underwater at over 250mph (and maybe they could do something about it, or maybe not...) but if a nuke is hidden on a ship then the Navy very well may allow them to dock.

    Super-sonic torpedoes would be undetectable at the target site by sonar. (Before they hit obviously)

    Sonar isn't radar, it uses sound and as such is limited by the speed of sound. If something is faster than light (yeah I know :) ) heading towards you, you can't see it before it hits you. Same applies to sound. A faster than sound projectile cannot be heard until it's sound wave hits you.

    Consider jets in the sky. The sound appears to come from an angle apart from where the plane appears to be, determined by its distance from the observation point and its speed.

    The net result of this is that a sonar net would have to be far-offshore to be of use on this one and also would need light speed comms to communicate to a torpedo station capable of destroying the projectile (ie. on the coast, preferably near the target).

    I don't know how pervasive the US coastguard sonar net is, but I doubt they funded an offshore boey sonar net. -Bye bye Karma! Voxol

  • What would be really cool is this, I was thinking about it the other day:
    The speed of sound in a medium is slightly effected by its frequency.

    Do the following:
    Emmit a frequency using your best directional technique (?)
    Raise(/Lower) the frequency at a carefuly calculated rate.
    All the waves will reach a certain point at the same time, this should (done properly) deliver quite a force at that point.
    This won't work too well in air because of pressure differences, but in water things are a whole lot more calculable.

    This has been brought to you by the great Transociter in the sky, in association with Brak-O-vision.
  • I think they gave them a fancy name, like sea-plane or something like that, but they were essentially "planes" that "flew" across the surface of the water with pontoons submerged.

    Ships which rise up on pontoons at speed are called hydrofoils, as you are on about Russian flying planes you might actually mean ikranoplans which fly at very low altitude.
  • Catamarans are double hulled sailboats

    A catamran is simply a double hulled water craft. It could be a sailboat, could be ore powered, could have an inboard or outboard motor or for that matter be a ship.
  • The original poster's reference to Russia makes me guess he was thinking of the KM from the JSC R.E. Alexeiev Central Hydrofoil Design Bureau. It was supposed to be a military transport.

    One advantage is no need to have a preasurised cabin (or for that matter store effluent from toilets.) Also IIRC the Soviets did experiment with having KM fire missiles. Though something like the Volge-2 would probably make a more sensible design base for an antiship "fighter". (even though it's considerably slower.)
  • The reason that airplanes and (some) racecars and some navy ships use gas-turbines for power generation is that gas turbines have a superior power/weight ratio compared to pistion engines.

    Also gas-turbines can be made to tollerate contaminants (e.g. sea water) in fuel and to be less fussy about the fuel itself. e.g. the Russians have a fighter aircraft which will run on just about any vehicle fuel you can put in the tank. Compare this to car engines which won't work at all if you put diesil in the tank. A piston engine, even a V8 or radial can produce a lot of vibration with a crankshaft being one more bit to go wrong. Aircraft, race cars and warships are all vehicles where reliable engines (and for that matter reliable engine managment systems) are very important.
  • Even after discovered by Western scientists, it hasn't been well developed outside of Russia. I don't know the reasons why, but maybe the efficiency / performance gains aren't enough to justify the lack of fexlibility - who wants something like a plane/boat that can't fly up into the atmosphere and maneuver like a plane, or travel efficiently on the water like a boat?

    Maybe not sufficent cost advantages to threaten the aviation industry.
    A large ekranoplan could easily carry the same as a 747, at similar speed. Also since it does not need to be presurised it can be made a shape better for fitting passengers and/or cargo in.
  • Just imagine, a "bomb" that goes off under a ship, releases a huge gas "bubble"

    This is exactly what any explosive does anyway. Detonation involves a solid or liquid explosive being converted to gas (typically including carbon dioxide, nitrous oxides and steam) very rapidly.
  • supersonic aircraft need to reach very high altitudes to be at all fuel-efficient.

    Only a handful of supersonic aircraft can cruise supersonically, most can only do so in short bursts.

    Supercav torps don't have that option; at any combat depth they are going to be almost literally plowing through a wall and rendering hideous stressors upon their shells.

    Water is going to be a lot harder on them than even sea level air. Thus a sea skimming missile is more likely to make a practical weapons system. These devices only being useful against submarines and torpedos. Even then having them able to fly most of the distance to their target, then dive makes more sense, IMHO.
  • Imagine a battle erupting near an area with schools of fish and suddenly dozens of supercavitating torpedos rip through the area on their way to a ship. Not only do we have the possibility of a good number of human beings losing their lives, but anything living near enough to the surface will be splattered.

    How well do you think these fish will manage with bombs dropping on them. It's easy to miss a ship dropping bombs from the air, but if you drop enough you are likely to sink it.
  • US Navy sonar will most certainly detect something appraching underwater at over 250mph

    But something undersea doesn't have to move at 250mph, it could move slowly, close to the seafloor...
  • Seriously, a man-portable nuclear weapon could detonate and probably not inflict massive damage beyond the first row of buildings/hard objects surrounding the port. Fallout would be an issue, although weapons designers can minimize this to an extent

    If weapon design can minimise fallout it can also maximise fallout. A terrorist might prefer to do the latter.

    I'm told that there are systems in R&D for over-the-horizon detection of nuclear weapons...

    Don't see how you could detect a type of weapon, methods of weapon delivery maybe. But you can't identify a bomb in a car or truck until it goes bang. With a nuclear weapon you don't need to park it as close to the target.
  • The effects of detonating a thermonuclear weapon (as opposed to your run of the mill nuclear weapon) high-above DC would be pretty devastating - depending upon the exact rating of the weapon, weather, topography, etc. you could reasonably expect much of DC to be destroyed.

    Note that for a high level airburst the damaged area is proportional to the cube root of the yield. A cluster of lower yield weapons could do more damage than a single high yield weapon.
  • In all honesty, a "suitcase nuke" (still kind of a big suitcase, but the word fits) attack is much more likely than a missile attack for a number of reasons:

    If the suitcase would be too big and heavy then cars and trucks are the obvious alternative. Probably even harder to spot since most cities don't have people carting 20kg suitcases around...
  • umm...how exactly are you going to detect a weapon which is travelling faster than the speed of sound (and therefore immune to sonar since sonar travels at the speed of sound) ? distance is immaterial in this case - the detection technology is slower than the weapon. if the weapon is a 100 miles away you still wont have time to evade.
  • supersonic weapons do just that - they travel faster than the speed of sound in the medium they are flying through. if encased in gas the projectile is effectively "flying" through air with extra drag due to the water on the edge of the air bubble. thats what makes these weapons so effective. note that most air to air missiles go mach 5+ which is WAAY faster than the speed of sound in water. its not that much harder to use the same technology but add gas bleeding through nozzles in the front to get the bubble encasing the missile.
  • True.
    But, it's already been done in water. I'll agree that they did it only with ammo Rounds (as in machingun Rounds), but it is feasable.

    Quote from Scientific American :
    In 1997 a research team at the Naval Undersea Warfare Center Division Newport in Rhode Island demonstrated the fully submerged launch of a supercavitating projectile with a muzzle velocity of 1,549 meters per second, which exceeds the speed of sound in water.

    There even is a cool picture of the actual firing.

    Murphy(c)
  • Not at all.

    I will agree with you that it only is a speculation, since no one (no even the Russians) really knows what happened. But is seems that you overlooked some of the articles passages.

    Quote from the given link :
    The tests of upgraded VA-111 ("Shkval") torpedo with a rocket propulsion are supposed to conduct on the submarine. It explains the presence onboard of two experts of "Dagdizel" military plant. The aforesaid modernization is supposed to be replacement of hard fuel on cheaper, but explosion-dangerous liquid one. The version is founded on the analysis of audio signals obtained USS MEMPHIS and the NORSAR Service.

    Now, if you also read the Scientific American article you will have noticed that they also talk about the Russian build Supercavitation torpedo name "Shkval"

    Quote from Scientific American Article:
    In 1977, after more than a decade of research and development, the Soviet navy secretly introduced a rocket-powered torpedo called the Shkval (Squall) that can "fly" through water at 100 meters per second (about 230 miles per hour) or more inside a self-generated gas cavity.

    Please refrain from yelling about any sensationalism, BEFOR fully reading both articles.

    Murphy(c)
  • I wonder if this has ever been attempted:

    I have heard that a ship can be sunk if an underwater eruption causes enough bubbles to be formed around the ship to lower the density of the water, thus causing the ship to sink because it displaces more of the less dense medium.

    Has such a weapon ever been devised or built? Just imagine, a "bomb" that goes off under a ship, releases a huge gas "bubble", which the hull "falls" into, to be swallowed instantly under the ocean, before the crew can even react...

    Possible?

    Worldcom [worldcom.com] - Generation Duh!
  • True, but these rely on concussive "shock wave" force to do the damage - I am thinking more on the order of a bomb, that explodes under a ship in a huge "wave" of bubbles, lowering the density of the water to the point where the ship almost instantly drops from sight, and is swallowed by the ocean (if it is even possible)...

    Worldcom [worldcom.com] - Generation Duh!
  • A nuclear blast from a weapon inside a ship at port will destroy not only the port it's at but the entire city.

    Also, US Navy sonar will most certainly detect something appraching underwater at over 250mph (and maybe they could do something about it, or maybe not...) but if a nuke is hidden on a ship then the Navy very well may allow them to dock.
  • In newspeak, there is no "god", and "are" is redundant. Here's the corrected version:

    You is unfunny.
    ------
    I'm a C++ guru ... What's STL?

  • Nice, except the H-bomb (which is a nuclear weapon) is about 3-4 orders of magnitude more powerful than the Hiroshima bomb. It could take out D.C.
    ------
    I'm a C++ guru ... What's STL?
  • > S. Glasstone & P. Dolan, The Effects of Nuclear Weapons [enviroweb.org], GPO.

  • What about inertia of the water displaced? (Score:4)

    by redelm ( 54142 ) on Sunday May 06, 2001 @10:22AM (#242636) Homepage
    Nice to reduce skin drag (viscous forces), but that's mostly important at low speeds. This is described by the Reynolds Number.


    At high speeds, the inertia of the water is more important: Water has to move out of the way of the projectile, and return after it passes. Since water is hardly compressible, alot of water has to move.

  • Re:The Kursk (Score:4)

    by LS ( 57954 ) on Sunday May 06, 2001 @09:18AM (#242637) Homepage
    The page written by Leonid A. Kharitonov that you linked states that the Russian government simply speculated on the idea of a failure of a secret new torpedo as the reason for the Kursk disaster, along with several other reasons. No mention of cavitation. So you are disseminating sensationalism and possibly misinformation by filtering out the rest of the page and submitting fourth hand knowledge (The Russian government - Russian reporters - Leonid Kharitonov - then yourself) to create fifth hand knowledge for the rest of the slashdot public.

    A lot of people never read the links, you know...
  • If you have one nuke, or a limited number, you really want bang for your (insert your preferred currency).
    The effect is lessened greatly as explained above.
  • a hydrofoil has lifting surfaces below waterlevel to lift the ship's hull(s) out of the water, like the wings on a plane. This greatly reduces drag. ekranoplanes have no contact with the water. The ekranoplane is closer related to the hovercraft than to a hydrofoil.

    //rdj
  • Civilian uses for super-cavitation have been proposed when the phenomenon was publicised, however there are some major drawbacks. The first is getting the object upto speed to form the cavitation which is over 500mph depending on size.

    The amount of energy required to do this without explosive launches is horrendous. As a body increases speed the resistance increases by a square. You cant use explosive charges with human passengers as they would be killed by the g-force.

    There is also the problem related to controlling direction, as any attemtp to change vector would require interaction with the surrounding see water massivley increasing drag.

    The final problem relating to this is navigating underwater hazards, admittedly the direct course can be calculated but the problems can include whales and debris. When the craft is travelling at 600mph+ and with the turning circle of the moon it may be difficult to identify and move around these objects.

    I cant see it ever being used for passenger carrying, maybe a high-speed cargo carrier for expensive goods, but with the immense costs involved it will be uneconomical for anything except colombian exports.

    As for changing the nature of modern warfare it might be a could platform for weapons of mass destruction aimed at sea-facilites, with all the detection nets aimed at aerospace delivery, it is concievable the such a munition may get through unscathed.

    Just my thoughts
  • The reason that airplanes and (some) racecars and some navy ships use gas-turbines for power generation is that gas turbines have a superior power/weight ratio compared to pistion engines.
    Actually, the biggest advantage that internal combustion engines have (aside from mechanical simplicity) is a wide power band. Many IC engines produce eighty percent of their maximum torque over eighty percent of their RPM range, which makes them tremendously useful in, for example, stop-and-go traffic. Turbines, though, tend to have very narrow power ranges, staying very low until you reach 0.9*max(constantRPM), where they rise rapidly until you exceed max(constantRPM). They don't spool up and down very efficiently, and it is so difficult to attain fine control that many applications simply use clutches and waste gates to blow excess energy off to /dev/null.

    So turbines are best suited for constant speeds and constant loads, like you will find in transport aircraft. Indeed, they do have high P/W ratios and they do run on a wider range of fuels, which is why the U.S. Army uses them in their main battle tanks.

    But if you want to see a truly twisted misapplication of gas turbine technology, check out this motorcycle [motorcyclecity.com].

    --

  • isn't that the right term for the Goatse man?

    Nah, I heard it was a British invention. Something about Tooth Beavers and stinky gumholes.
  • (And to the wales' credit, beaches don't have warning labels from the Surgeon General.) wHales on the other hand get warnings from the Sturgeon General and stay away from the things (that and the difficulty of getting a light at 30 fathoms)
  • What exactly do weapons have to do with war? Sure, that might be one use but I get some personal enjoyment out of shooting off an arrow every once in a while. Ever play darts? Drop a few hundred thousand of them out of a plane and you could have a heck of a war. Very painful I'd imagine.

  • What about Whales? (Score:5)

    by Sleen ( 73855 ) on Sunday May 06, 2001 @08:56AM (#242645)
    One of the theories on what drives whales to mass beachings, other than the possibility of viruses; is underwater noise pollution. Its hard to imagine that an entire pod of whales would succumb to the same infection. Since these highly social(Eusocial?) beings depend on long distance communication through corridors of reflection; isn't this technology just going to drive them MAD?

    What kind of impact would this weapon, or mode of travel have on intelligent aquatic life?

    As usual, unless you are human; you have no rights at all.
  • anything going that fast is going to make alot of noise. Plus thier russian, thier stuff makes a lot of noise anyway. So they strike a hit on one target, then the attacking sub finds an entire carrier group coming after it after they trace the sound, assuming the sub was able to get close without being detected. Subs are pretty much defencless against an air attack. If found before the sub got in range, it would still be in big trouble. BTW, indy cars (the type used in CART) go in excess of 230 mph
  • Environmental concerns ... would have to be considered

    Yes, as we kill each other for the benefit of the "happy few", let's make sure that we don't kill off all the whales. The happy few like whales.

    ... history shows that military technology often finds financial support when money for other purposes is scarce.

    Especially more recent history, like the past 100 years. With the new recession, we can look forward to more of this kind of work, if we're lucky enough to find any work.

  • I think they gave them a fancy name, like sea-plane or something like that, but they were essentially "planes" that "flew" across the surface of the water with pontoons submerged. The general application seemed to be for transportation of people, and cargo. The supercavitating technology was to advance this mode of transport further by reducing drag. This would make for very stable flight across the surface of the water, with the pilot being able actually see what's in front of the plane.

    As for military applications, I suppose that escaping radar detection might be one motivation. I don't think that a supercavitating vessel is undetectable by sonar though.

    It's interesting how this keeps popping up in the media. Supercavitating projectiles and vessels have been in use for over 40 years. Yet the world hasn't really stopped to take note of this technology the way it would seem to merit. Kind of like the turbine engine (like jet engines used on commercial airliners) when it was used on vehicles -- got great results in the indy 500 in the 1950's but never went into production because the engine had no crankshaft, no valves, no pistons, no transmission -- not much need for lubricants.

  • You've got a better memory than I do. Guess I should have been taking notes when I was watching the history channel ")
  • seems kinda silly -

    bullets aren't steerable and they're still the most commonly used munition :)

  • In the true spirit of slashdot, here are some pseudo technical ramblings made with little knowledge of the underlying principles:

    3. I kind of doubt the sonic attack thing will work...your power output just gets spread out so quickly (starts approaching d^3 the farther out you go) that it wouldn't be effective at reasonable distances. Even if you force a torpedo out of super-cavitation at 1000 yards out it's still going to smash into you at a good clip. It might be effective at small projectiles, but then the problem becomes taking down much larger numbers of projectiles from (potentially) very different vectors.

    5. I don't think any ablative armor is going to work; even the mass of a shell is significant, so you would need to expend a massive amount of energy to have much effect, especially since the water would strongly resist this effect. The situation is much worse when you are talking about a 5000 lb. torpedo...not only are you going to be unable to stop it, if it explodes anywhere near the target its probably a "hit".
  • That list is only of the INITIAL possible causes. If you actually READ the site you would find out that they rule most of these out and then they go into an accurate and detailed timeline of the rescue attempts and other post-sinking events.

  • The Kursk (Score:4)

    by SaxMaster ( 95691 ) on Sunday May 06, 2001 @08:51AM (#242653)
    The sinking of the Kursk may have been caused by the premature explosion of one of these "supercavatating torpedoes." This site [museum.navy.ru] has some good info.

  • The vehicles of which you speak are "ground effect vehicles" or more precisely "wing in ground effect" (WIG) vehicles. The Russians call them Ekranoplans and they scared the shit out of the CIA back in the 70's when a spy photo showed this HUGE plane on the caspian sea coast, a plane whoich turned out to be an ekranoplan. A good old google search will gived you loads of references.

  • Modern smokeless gun powder was invented in the late 1800s. I know in America the patent is held by one of the Duponts, either Lammot or his son Pierce IIRC.

    As for the 4wd, the first really popular one was the Jeep which essentially ushered the horse out of modern warfare in 1941. I'm sure someone made one before that. Note that the Germans were still using horses in WWII to pull artillery and such.

  • Actually, further down the line is the word "most" and that thats the important one.

    China actually invented black powder, not gunpowder. gunpowder is a safer and more powerful form of black powder and was created for military use (in artillery). 1400s I believe for gunpowder.

    4WD was created because the limits of what horses could do was showing up and the military needed a replacement for the horse. It didnt gain popular use until ... mid 1930's I think. Civilian use came after WW2 when people discovered the joys of off-road driving.

    And go way back on the foods. An army travels on its stomach.

    Yeah, the military has a huge budget for R&D, but MOST of the research eventually has a civilian use. What about GPS? or maybe kevlar or carbon fiber? (many tool shafts are now these high-tech composites), how about communication satellites for things like TV and pagers? All of space is (was) a huge military funded operation. Of course there are bad things too. Look at the Manhattan Project. Sure we got a great source of cheap energy, but we also got the bomb from it.

    Kevin
  • sorry forgot this in the other post. You asked where the majority of taxpayer money went? Welfare and other social programs, not the military.

    Kevin

  • Re:Just what we need (Score:3)

    by Milikki ( 103463 ) on Sunday May 06, 2001 @09:06AM (#242658)
    Hey George, get a clue.

    The military has ALWAYS been the source of most technological innovation. Everything from gunpowder to 4-wheel drive and non-perishable foods all came from military applications. It was only later that civilian uses were found for the stuff.

    And remember, without Beer man would never have gone to the moon.

    Kevin
  • One of the theories on what drives whales to mass beachings, other than the possibility of viruses; is underwater noise pollution. Its hard to imagine that an entire pod of whales would succumb to the same infection. Since these highly social(Eusocial?) beings depend on long distance communication through corridors of reflection; isn't this technology just going to drive them MAD?

    What kind of impact would this weapon, or mode of travel have on intelligent aquatic life?

    If whales are intelligent is still subject to discussion, dumb enough to beach themselves anyways. But to answer your first question: Probably no effect at all. Beachings are not limited to this century, but have been recorded in previous centuries. In Europe, one of the main reasons of beachings is whales taking a wrong turn when they reach the UK and swimming into the North Sea. The North Sea is too shallow to support the massive creatures. They get into all kinds of trouble, get ill and beach.

  • The last fifty years have been the most peacful period in human history

    Any proof for this far-reaching statement?

  • Any conception of what the word "proof" could possibly mean in your ridiculous context?

    Well, if you don't like the word "proof" how about "justification" or "positive evidence"?

    If you make a sweeping statement like that you should be prepared to defend it.

  • Now, what do we have? Little brushfires that would have been considered to be, roughly, peace now are all that's there, and they draw attention from the major world powers which fall over each other to stop the horror. It's certainly a safe time to be alive as far as wars.

    If you lived in Africa, parts of south Asia or southern America you might have thought otherwise. There are plenty of people killing each other at any given moment of time. And don't forget that the war of completely unprecendented scope involving all major power happened only a little more than 50 years ago.

    Also how about the 19th century? The end of the 19th century was remarkably peaceful. In fact the sentiment back then was quite close to what it is today - people believed in technological progress, equality, etc. As now most people believed that the civilization reached an advanced stage where major wars are unlikely.

    Just because it is safe here and now does not make it a safe time to be alive.

  • Re:Hydrofoils (Score:3)

    by ozbird ( 127571 ) on Sunday May 06, 2001 @02:20PM (#242665)
    Catamarans are double hulled sailboats, small difference :)

    "Catamaran" is a term used (perhaps loosely) for any twin-hulled vessel e.g. the Incat [incat.com.au] high speed ferries.
  • Quck... name one Navy besides USN that has a realaircraft carrier. (It's a very short list)
  • you know.. that splash you used to make in the pool when you were a kid?, now you can reach the bottom faster and harder! yes kids, just fart while jumping and you'll do a super-cavitationnal bomb :)

  • Assume the bomb is in a shipping container. For this to work the container must be in the top.

    Phase 1 - Blow out top of container (explosive bolts - one side goes off mmiliseconds before the other one)

    Phase 2 - Helium ballon connected to the bomb self inflates from auxiliary bottles of pressurized gas

    Phase 3 - Bomb explodes using a pressure detector or timer (even if the ballon get's tangled on something the timer will take care of making it explode)

    Of course this is just an amateur's idea (i can think of a lot of possible problems)

  • This wasn't new last time or the time before that

    The article post clearly says, "We've done a couple of articles about these weapons before, but Scientific American has good explanations and diagrams and some new information."

    Stop being such a karma whore =P.

  • A recorder that was recovered from the Kursk had picked up a conversation around the time of the explosion...

    Captain of Kursk: What happen?

    Chinese Sub Officer: Somebody set up us the bomb.
    you know the rest

  • This issue was raised on the SFCONSIM-L mailing list not too long ago. A number of important points were brought up. Please consult the SFCONSIM-L archives (sorry, I don't have a URL) for the full discussion.

    First, supercav torps move at just over the speed of sound in water... which is considerably slower than how sound is in air. They might come up with some incredible numbers, but be forewarned: airborne weapons will still be incredibly faster.

    Second, these things are LOUD. Now, they move faster than sound in water, so in that sense they are very sneaky. They'll hit before you know they're there. However, the defense for this is a distributed sonar net and a far-flung destroyer screen -- which is what GOOD navies do to protect their high-importance assets already, i.e. battleships and carriers. The destroyer screen and any roving underwater assets will detect the torpedo peripherally, notify the central asset vessel, upon which appropriate precautions will be taken.

    In this sense, the supercav torpedo seems to make a better point-defense weapon when you know the bad guys are firing nuclear torps at you, or you absolutely cannot risk any damage whatsoever to your central asset (such as a carrier conducting flight operations.) A small, supercav torp fired in interception with an enemy torpedo. It could be a simple kinetic impactor, or a small explosive charge to spank the bad guys' torp, enough to generate a small pressure wave which will act like a wall to the enemy torp.

    However, cavitation is extremely hard on a body and causes a lot of drag and heat -- supersonic aircraft need to reach very high altitudes to be at all fuel-efficient. Supercav torps don't have that option; at any combat depth they are going to be almost literally plowing through a wall and rendering hideous stressors upon their shells. Add to this their incredible fuel consumption, and you have a frankly short-duration weapon. You won't be able to fire one of these puppies from the other side of the Atlantic, and they're not going to be 'supercruise torpedoes' by any stretch of the imagination.

    They're a cool idea, though, if for no other reason than to have the fastest torps in the depths. *rimshot* =)

    ---
    Chief Technician, Helpdesk at the End of the World

  • Just like jet, prop, and other air-based propulsion technologies are only used to kill people?

    Militaries are loss leaders, like racing teams for car manufacturers, but the technology is something that can be applied to anything; it takes a genius to figure it out, and a genius to apply it, but once we do, the 'capitalist' system rewards them for the efficiencies they exploit.

    Geek dating! [bunnyhop.com]
  • Actually, I think the underlying principles may have merit.

    You don't need to dispell the bubble at 1000 yards. You need to destabilize the bubble enough for tail slap to kick in, and you only need it far enough that the explosive warhead, if it detonates, doesn't damage the sub. Even 10 yards may be enough to soak up the explosion.

    The same with the ablative armor. It doesn't need to even touch the warhead, because the destroying the bubble would be worse than tail slap; a wall of water rushing at the warhead at 200mph will do all the work you need.

    A 5000lb torpedo would impact the water no different than if it were hitting a concrete barrier. The water would soak most of the impact. However, what I don't know is what range is necessary for the water to do all the work for the military.

    Geek dating! [bunnyhop.com]
  • The speed of sound is determined by the medium in which you are measuring sound, so that in the air at sea level it can be ~700mph, but underwater it is considerably slower, I think. Regardless, if you read the article, they already have projectiles that travel faster than the speed of sound, traveling at 1.5km/s

    So the bullet travels faster than the sound waves it produces, which means that a moving sub cannot 'hear' the bullet with passive sonar, and unless it uses active radar, cannot do a radar scan either (I think active radar can be detected by other subs...)

    And besides the main point, the Soviet Squall has already been recorded/suspected to be capable of reaching speeds of 230miles per hour!

    Geek dating! [bunnyhop.com]
  • Read the article;

    They are talking about aluminim oxide powered turboprops traveling at about 200 meters per second, which is about ~400 miles per hour.

    They also have been able to launch projectiles at about 1.5kmps, which is over 7 times faster, or about 3200 miles per hour, much much faster than the speed of sound under water or above water.

    Meaning that the shock waves it gives off cannot be deteced by sonar!

    Geek dating! [bunnyhop.com]
  • Re-read my post and re-read the article, they already have projectiles that travel at 1.5kmps which breaks the sound barrier.

    Geek dating! [bunnyhop.com]
  • Here, let's spark one.

    Super cavitating weapons would travel faster than the speed of sound, so it cannot be detected sonically.

    The gas/water interface may be very radar noisy, so that might still work, I don't know.

    A sonic attack, akin to a laser, should be able to collapse or deflect super cavitating weapons.

    Focus the water waves/sound waves into a beam like weapon in the path of the super cavitating weapon, feed more energy into the bubble than it was designed to handle, and destabilize the cavitating devices capacity to create a stable bubble, forcing tail slap and mis-guides.

    Or something as simple as 'ablative' armor, in which surface mounted explosives destroy the bubble and using the shockwave/water as a weapon against super-cavitating devices.

    Geek dating! [bunnyhop.com]
  • Not ALWAYS, maybe always but not ALWAYS.

    Gunpowder was first used in china for fireworks, I could be wrong here but I don't think they used it for warfare until the europeans got a hold of the stuff.

    4WD was first built in 1898, when the worlds armies were still on horseback.

    Non-perishable foods, how far back do you want to go, the first salted meats, dried fruits etc, hard to discern if they were first used by the military.

    Now on to my main point, the reason that the american military 'invents' so much stuff is that they have the money. Where does the majority of american tax payers money go?

  • If the effects of damage through blast overpressure scaled linearly, then you'd be correct. Unfortunately, it doesn't quite work that way. (Again, refer to the Effects of Nuclear Weapons, or the large body of translated former-Sovet texts available in university libraries that cover Strategic Studies).

    The effects of detonating a thermonuclear weapon (as opposed to your run of the mill nuclear weapon) high-above DC would be pretty devastating - depending upon the exact rating of the weapon, weather, topography, etc. you could reasonably expect much of DC to be destroyed. A high-altitude airburst would minimize residual radiation effects, maximize blast damage (greater line of sight area for blast overpressure damage - the primary kill factor for a thermonuclear weapon) - and you'd make quite a mess.

    On the other hand, ground-bursting a thermonuclear weapon on a ship in harbour is going to be a LOT less destructive relative to a well-placed airburst. You'll have more secondary radiation issues to deal with (the fireball really HAS to reach ground level, by definition) but blast damage is likely to be relatively localized by the quantity of solid matter it has to pass through/over to knock more stuff over. Remember, blast reflects/wraps on solid objects that don't break - so while the first few buildings would crumble against pressure, the buildings behind them would receive MUCH weaker effects. Detonating a full-scale thermonuclear weapon on a ship really is a bit of a waste because of this!

    All of this ignores the strategic lunacy of targeting cities in general, but that's another can of worms. :-)

  • Re:Ooooh, we're so scared. (Score:5)

    by TheBracket ( 307388 ) on Sunday May 06, 2001 @09:40AM (#242713) Homepage
    A nuclear blast from a weapon inside a ship at port will destroy not only the port it's at but the entire city.

    Depends upon the nuclear weapon. :-) Seriously, a man-portable nuclear weapon could detonate and probably not inflict massive damage beyond the first row of buildings/hard objects surrounding the port. Fallout would be an issue, although weapons designers can minimize this to an extent - certainly not as bad as the apocalyptic impression spread by phrases such as that one. Remember that people in shelter's around Hiroshima ground-zero were relatively unscathed - and train service for the city was functional again in a few hours. Nuclear != Armageddon, just a particular type of weapon.

    Highly recommended reading:
    S. Glasstone & P. Dolan, The Effects of Nuclear Weapons, GPO.

    Also, US Navy sonar will most certainly detect something appraching underwater at over 250mph (and maybe they could do something about it, or maybe not...) but if a nuke is hidden on a ship then the Navy very well may allow them to dock.

    This is a big issue, and one that the Pentagon is familiar with (although navy brass tend to reject the notion that nuclear weapons will ever be used). In a recent wargame in which I participated, red team was able to do a ridiculous amount of infrastructure damage to the US with this very tactic. I'm told that there are systems in R&D for over-the-horizon detection of nuclear weapons... although I have no idea how that would work. For all I know, it's military vapourware.

    It should be possible to detect inbound weapons travelling at >250mpg, the question is what to do about it once you've detected it (the exact same problem as with ballistic missiles). Shooting it down requires the existence of a pretty impressive infrastructure designed to stop that particular type of attack - and as you say, probably won't help against the shipping boat packed with explosives.

  • I think you mean hydrofoils, yet another word I learned thanks to GiJoe cartoons. And knowing is half the battle...

    Catamarans are double hulled sailboats, small difference :)

  • Since these highly social(Eusocial?) beings depend on long distance communication through corridors of reflection; isn't this technology just going to drive them MAD?

    What the hell do whales do when volcanoes erupt underwater, or earthquakes occur? I would think this has much more of an effect on them. Not only is there a huge BOOM and lots of rumblings that can be heard for many thousands of miles, but their precious "corridors of reflection" get changed all the time as islands form. Whales have had to deal with underwater noise for much much much longer than humans have walked the earth. I don't think supercavitation is really going to hurt them much. (Heh heh...unless one gets shot...)

  • more than just geeks.

    Deepangel and Supercavitation [deepangel.com]

    I take that back, this is a game for geeks i suppose, heh =).

    Before they develop supercavitation too much, i really think they need to work on being able to get DEEPER because we have yet to explore a large portion of the earth simply because its too deep.

  • People are more important than animals!

    If this story is true, I'm sure that the activists were concerned more about the extinction of entire species of whales than about any individual whale.

    The human race, on the other hand, is in no danger of extinction by hand grenades.

    It's arguable whether a small number of people are indeed more important than a major animal species. The former is certainly more replaceable than the later.

  • Re:What about Whales? Probably Not (Score:5)

    by Waffle Iron ( 339739 ) on Sunday May 06, 2001 @12:41PM (#242724)
    If whales are intelligent is still subject to discussion, dumb enough to beach themselves anyways.

    However, they're not so dumb that they smoke cigarettes.

    (And to the wales' credit, beaches don't have warning labels from the Surgeon General.)

  • "Or du you only listen to Greenpeace pullshit,"

    I listen to all sides.

    "portraying whalers as psycho killers?"

    they are indisputably killers.

    "That's just pathetic."

    I agree.

  • Supersonic is pretty hard to do underwater - sound travels much faster there.

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