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Sonic Torpedo Defense
dylanduck writes "How do you defend a ship against torpedoes? According to the US Navy, you line the hull with loudspeakers and blast the incoming missile with such a devastating blast of sounds that it explodes." When asked about the possible ecological effects on marine life the military had no comment.
Except in this case you get both.. ( even the summary stated this ).
But, its once again a trade off.. Man or Animal.
War isnt always fair.
---- Booth was a patriot ----
Would this damage submarines sonar or other listening devices?
Actually, being an acoustician, I would be willing to bet that they would use a phased array of loudspeakers. With the correct phasing of the speakers, some pre-determined "point" in the water could be driven to very high sound pressure levels, while the remaining ambient noise, while still loud, may not be all that dangerous. This would occur as a transient excitation from the various loudspeakers propagates away from the source and coalesces at the point in the water where the torpedo is located, the point where a very large pressure spike is generated. There are plenty of smart researchers in the navy and I have my doubts that they would use anything other than a phased array. And by the way, this is the same methodology that they use to destroy kidney stones.
Name: Mr. Anon E Mouse; SSN: 555-55-5555
Is a nuclear reactor really worse? Or is that just the knee jerk reaction?
So did you wake up today saying "I'm going to proove myself to be an idiot today - not once but twice over!"
I hope that was your goal because otherwise you really didn't get much done today.
On "Shiny missiles". How do you make a perfect mirror? Oh you can't? The mirror material has to absorm some percentage of the energy coming from a laser whcih thus vaporises said material (an dmissile skin), not to mention teh issues with keeping the object perfectly shiny in flight?
On your "Nerf Missile". At what point do you tell you've hit somehting if you're behind enough layers of foam to pad yourself against running into something that feels like a brick wall? What wall is real and what is not when the impact of hitting it is the same? Do you just simply not explode ever and hope the ship you were aiming at becomes Rather Alarmed at the hurling of nerf objects at it? I guess that's cheaper than real torpedos.
And tehre are at least two moderators out there that can hang thier heads in shame as well. I'll see y'all in Metamod along with the rest of the people that udnerstand basic physics.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
As a former naval submarine lieutenant, this is pretty interesting... Indeed, our modern torpedoes (ADCAPs) travel at high speed, track on both passive and active acoustics, and rely on active ranging to detonate at an ideal distance under the ship. That's right, under -- torpedoes do the most damage by detonating a small distance (on the order of a couple dozen feet) below the center of a hull. The void formed from the detonation causes the target's hull to buckle/crack/shatter inward due to its own weight. A single ADCAP can in theory sink an entire carrier, but sub captains typically shoot two b/c the carrier is typically the primary objective. The kind of acoustics described in the article would be tough for even an ADCAP to work around, not to mention it takes our contractors many years to turn around software upgrades to the weapons that would filtering to increases its chances. Then again, good this is a DARPA project, meaning it'd take 5+ years to see any deployment in the fleet anyway.
The most cost effective anti-torpedo weapon a surface ship can have is the nixie. It's a towed (inflated, I believe) thing that trails the ship with ship-signature acoustics running on it, sucking up any torps on the ship's trail. Given their low lost, low maintenance, and (extremely!) high effectiveness they're the best deal in town.
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I've asked him about how powerful the sonar was and to give you an idea how dangerous it is he told me about some standard submarine procedure. Basically, if a submarine comes under threat from enemy frogmen or divers, the defence the sub has is to turn the active sonar on and start pinging. If a diver is underwater and within a couple hundred yards, he will die from the intensity of the sound under water. In other words the sonar is VERY powerful. Trust me a 200db blast will likely give someone a very bad day if they are near by.
and currently stationed by iraq. While I say the more defensive weapons the better, if we have to do it at the expense of making all the whales extinct I say its not worth it. This isnt about saving plankton here, this is about not accidently blowing away the eardrums and thus killing thousands of whales and other marine creatures. There have been experiments with this technology and coincidentally there were massive beachings as the marine mammals could no longer navigate correctly. There are billions of us, I can't say the same for the whales.
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Just about anyone with a relatively big boat has to repaint the hull with antifoul paint every couple years. Not really that nasty, now, it's simply marine paint mixed with a bunch of (correct me if i'm wrong) aluminium dust. The older stuff used primarily copper, which had a few adverse effects on sea life.
Apparently some of the Cajuns down south use cayenne pepper, and they claim it works the best, but hey, to a cajun, cayenne pepper's good for damn near anything.
The navy these days has actually been using some pretty wierd coatings for ships, although mainly subs, in order to reduce friction.
My other Sig is
If this is to blow torpedoes out of the water, I've got one question. If anyone's running sonar, and you blast a torpedo out of the water, wouldn't you tend to alert everyone else around you??
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
You have to prepare for the next war, not the final war. Believing that noone is going to use a torpedo against a US warship because everyone is afraid of the US military is unfounded. How many countries would love to torpedo a US warship if they could just get away with it? If we started bombing Iran, do you think they would hold back on using their submarines against our aircraft carriers? One carrier is the sixth largest air force in the world. Destroying an aircraft carrier isn't just a tactical victory. Due to its power and capabilities (and perhaps our fear of losing another one), it could radically change how a war is fought. There is a reason that the Russians designed cruise missiles and nuclear torpedoes specifically targeted to our carriers in the Cold War--even though they had a 3-tier nuclear defense program (bombs, ICBMs, SLBMs). They were preparing for the next war, not the final war.
All I know about naval warfare, I've read from Tom Clancy books, but...
Isn't blasting the ocean with a massive sound wave a pretty good way to advertise yourself to every submarine and ship within 5,000 km? Obviously, at least one enemy has a good track on you at that point, but we're talking about basically shooting up a flare for any interested parties. Wouldn't that completely compromise any convoy that a navy ship might be protecting, to say nothing of a valuable carrier group? Even sending an identifiable signal in just one direction would be pretty inscrutable behavior from one of todays stealthy ships.
Seems to me that this system is not likely to be used any time soon. Of course, tested is another matter...
To say nothing of the sonarman's eardrums.
That's silly. What if we have data that says that our potential weapon obliterates wildlife? Should we toss the idea and move on? Let's look at what we have now: Nuclear weapons obliterate wildlife. Fair enough, nuclear weapons are grossly indiscriminate; toss 'em. Conventional explosives obliterate wildlife. Ok, toss those too. Artillery isn't very green, either. In fact, machine guns aren't particularly enviro-friendly. Get rid of 'em. And let's just forget about a whole platoon of soldiers tramping through the forest, crushing wildlife, shooting guns, and throwing grenades.
I guess we don't have many options left, do we?
Sounds like a nice situation to me. A guy can dream, can't he?
I'm 90% sure I know what this is for. I'm not a naval warfare specialist, but I am a scientist with an interest in these things.
In the 1990s, the Russians developed the prototype for what would later be termed the Shkval or Squall supercavitation torpedo. Knowing the Russians, the Chinese probably have them too.
Cavitation is a phenomena where a body moving through the water pushes the water out of the way so fast that it creates bubbles around the object (fast = lower pressure = water vaporization = bubbles). You may have heard of propellers cavitating - that's where small bubbles of water vapor form then burst on the low pressure side of a prop blade, causing lots of noise and even damage to the blade when they implode.
Supercavitation, on the other hand, is an intentional phenomena where a blunt-nosed object is shot through the water, creating low pressure vortices on the sides. Air or exhaust gases are injected into these vortices, creating a static "bubble" around the object that drastically reduces friction - perhaps up to an order of magnitude. You have to fire these things at about 50mph or greater to start the supercav effect going, effectively "handing off" the bubble to the torpedo, which then sustains it.
The numbers on these torpedoes are incredible: we're talking about a 300mph torp carrying a 460lb warhead with a range in excess of 7000 yards. That's the tame version - others carry nukes. In other words, carrier-killers.
Supercavitation torpedoes, as you can imagine, are incredibly noisy and easy to detect - you just can't get away from them because they're so fast. This sonic projector essentially sends a high-energy single pulse through the water directed at an incoming torpedo. That pulse probably wouldn't be able to crack a torpedo - you'd probably need on the order of 250-500PSIG overpressure to do that, (scuba tanks contain 2000PSIG regularly). You wouldn't be able to detonate the high explosive, because you need a wavefront speed above the detonation velocity, which for C4 is about 7000m/s (much slower than the speed of sound in water, 1482m/s).
I don't have the time right now to spin the equations, so I could be wrong.
However, you would be able to disrupt and dissipate that bubble around an incoming supercavitation weapon with a high-energy sonic pulse. Break that bubble, and the torp stops dead in the water because it can't reform the bubble around itself. If it mistakes that sudden stop for a ship hull - boom.
'Be always mindful, even when ditch-digging.' --D. T. Suzuki
Next time I'm on a submarine under fire though, I won't be wishing a torpedo away based on some ideals of pacifism.
I will satisfy your request by calling you short-sighted. Humans on submarines are an expensive luxury. Humans have sailed these subsurface warships for over a hundred years, but it is unlikely they will sail them for a hundred more. I think we all hope that whales will be around for at least the next hundred and more years. Technology that threatens their existence while preserving something we won't need much longer is an unacceptable tradeoff.
Submarines' primary value is providing an unpredictable launch location for missles. In short order, we should be able to accomplish the same with drones more cheaply and effectively. Without life support overhead, these drones should be able to operate indefinitely underwater without surfacing. This acoustic detonation project is a waste of tax dollars supporting a system that has a limited lifespan.
Seth
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You're right. I air-to-surface torpedos are kind of over these days. It's all about air to surface missles now.
My big complaint on this is it's an example of the military's tendency to spend where there isn't a real-world problem. This problem climbs all the way up into the executive branch. In his first term, George W. Bush decided to pull the US out of the ABM treaty. This was because our government wanted the freedom to develop technology to destroy ICBMs. Even after Sept. 11th, the US government wasn't convinced that low-tech is the more plausible threat. The entities who will actually do us harm aren't going to invest in complex systems that send explosive material guided by computers and lasers.
In Iraq, our blind eye to low tech has been exploited with roadside bombs that penetrate the thinly-armored underbelly of our troop transport vehicles. Same with the tens of thousands of RPG launchers menacing our soldiers. More recently, the military has improved the shielding beneath these vehicles and figured out better ways to protect against RPGs. The current method is to erect galvanized tin around tanks and APCs so that the RPG will detonate outside the vehicle. It's a directed charge, so without an impact, it causes exponentially less harm when exploded beside the vehicle. Here's a description of an electric force-field concept to protect against RPGs.
Anyway, I hate to see money misdirected at defending against implausible scenarios while very real threats abound. And to sacrifice whales for the cause is icing on the cake of waste.
Seth
$5 / month hosted VPS on linux = awesome!
The primary use would be against sea mines - cheap, and not much of a signature - if you don't mind hosing the local fishlife.
But modern stuff is not that dumb, or if they were, they wont be for long. Decoys have a short shelflife.
No sane nation will use torps - any that got close enough to fire - will not be leaving. Cruise missiles have made most subs obsolete.
So they should take this white elephant and stick it in New Orleans to kill breeeding mosquitos, carp and the rat population. Locals may try to swipe panels some to fit under their car for custom auto sound competitions. Someone is taking their car sub-woofer fantasy to the extreme and scamming some research payments.