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Posted: 1/4/2012 8:29:12 PM EDT
[Last Edit: 1/4/2012 8:44:34 PM EDT by retgarr]
Within opsec of course, what can those of you in the know tell me about them?

I understand basically how they work, but would like to know more about them operationally..

Such as why don't we have any, what kind of threat are they, what is their downside, and what kind of defense is there against them.

I've seen bits about them and they sure seem damn scary.
Link Posted: 1/4/2012 8:30:33 PM EDT
[Last Edit: 1/4/2012 8:30:53 PM EDT by Dagger41]
If it's cavitating, it's going nowhere superfast.
Link Posted: 1/4/2012 8:31:14 PM EDT
they make bubbles
Link Posted: 1/4/2012 8:33:10 PM EDT
Black talons for subs man.
Link Posted: 1/4/2012 8:34:43 PM EDT
Originally Posted By Dagger41:
If it's cavitating, it's going nowhere superfast.


Yeah, but the question was supercavitating.
Link Posted: 1/4/2012 8:35:27 PM EDT
Link Posted: 1/4/2012 8:36:56 PM EDT
Think of them like underwater bottle rockets. Short range underwater rockets.

If you can get within 7-8 km of your target, and perfectly lined up with a direct shot, and do it without alerting them so they don't change course, you might be able to hit them with a weapon that won't give them enough warning to dodge or deploy countermeasures.

Maybe.

More likely, you'll miss.

Also decent chances exist that it'll just blow your ass up before you manage to fire it, like what we suspect happened to the Kursk.
Link Posted: 1/4/2012 8:39:50 PM EDT
Cavitation here is used for drag reduction. Now if the screw is in the rear, such flow regime would make the screw also cavitate. Forget rocket/mixed phase stream propulsion, too inefficient. The screw must be far behind the flow convergence, a long prop shaft works. Drag is limited by cross sectional area, skin friction is countered by the induced cavitation.

Downside? Range. They are thirsty beasts.
Link Posted: 1/4/2012 8:48:31 PM EDT
They do not work worth a fuck in water with fluoride in it.
Link Posted: 1/4/2012 8:49:39 PM EDT

Originally Posted By WilliamGray:
They do not work worth a fuck in water with fluoride in it.

but the cavitation kills the germs that cause bad breath
Link Posted: 1/4/2012 8:56:02 PM EDT
Seems expensive, and like a lot could go wrong very very quickly.


Next up: Supercavitating subs.
Link Posted: 1/4/2012 8:57:38 PM EDT

Originally Posted By Keith_J:
Cavitation here is used for drag reduction. Now if the screw is in the rear, such flow regime would make the screw also cavitate. Forget rocket/mixed phase stream propulsion, too inefficient. The screw must be far behind the flow convergence, a long prop shaft works. Drag is limited by cross sectional area, skin friction is countered by the induced cavitation.

Downside? Range. They are thirsty beasts.

Makes a helluva lotta sense. I wonder how long the prop shaft would have to be, and if it would fit in conventional sub tubes & still get range that's worth a damn.
Link Posted: 1/4/2012 9:04:14 PM EDT
Super cavitation can only occur at very high speeds.

So the best way to acheive it is to drop it from aircraft or use it as a missle that enters the water.

Other than that water is thick and launching an armed warhead into that stuff at high speed is a little hazardous.
Link Posted: 1/4/2012 9:10:33 PM EDT
[Last Edit: 1/4/2012 9:12:19 PM EDT by BP03]
Russians have had one since the late 70's..

VA-111 Shkval

http://en.wikipedia.org/wiki/VA-111_Shkval

ETA: Supposedly the Iranians do too, called the Hoot, pretty much a knockoff of the Shkval
Link Posted: 1/4/2012 9:12:04 PM EDT
If you are referring to the torpedo that creates a envelop of bubbles to reduce drag to reach super speeds underwater.

The problem is turning. Here is an article from PM.

Submarines peaked in power and relevance during the Cold War; there has since been a shift in focus to aircraft-based combat, and subs have become budget-cut victims. But subs are still prized for their ability to sneak about global waters undetected and to defend surface ships from attack. Many U.S. subs are being converted from missile launchers into delivery vehicles for special operations troops.


But the supercavitating torpedo—a rocket-propelled weapon that speeds through the water enveloped in a nearly frictionless air bubble—may render obsolete the old submarine strategy of sly maneuvering and silent running to evade the enemy. The superfast torpedo could be outfitted with conventional explosive warheads, nuclear tips or nothing at all—a 5,000-pound, 230-mph missile could do enough damage on its own. The Russians invented the concept during the Cold War, and their version of this underwater killer—dubbed the Shkval (“Squall”)—has recently been made available on the international weapons market; the United States, of course, wants a new, improved version of the original.


The hard part about building a rocket-propelled torpedo isn’t so much the propulsion as clearing a path through the ocean. Water creates speed-sapping drag; the best way to overcome that drag is to create a bubble that envelops the torpedo—a supercavity. A gas ejected uniformly and with enough force through a cavitator in the nose of the torpedo will provide such a bubble, permitting speeds of more than 200 mph and a range of up to 5 miles (traditional torpedoes have slightly longer ranges, but lumber at only 30 to 40 mph).
Though submerged, the torpedo remains essentially dry, with a frictionless surface. “That sounds easy, but doing it is extremely difficult, especially if you’re trying to steer,” says Kam Ng, program manager for the torpedo at the Office of Naval Research, which has been developing the weapon since 1997. “If your torpedo moves in a straight line, you just aim and shoot,” says Ng. “That capability already exists with
Shkval. But the U.S. vehicle will be more capable—it will turn, identify objects, and home in on the target.” (Improvements to the torpedo to make it steerable likely froze when the Soviet Union collapsed, says GlobalSecurity.org’s Pike.)


Among the greatest challenges for U.S. torpedo researchers is developing detection and homing technology that will enable the torpedo to distinguish an enemy sub from, say, a rock formation, says Ng. Also tricky is finding a way to control the gas bubble to permit those course changes. “When you turn, the bubble distorts because it is no longer symmetrical,” he says. “So you have to compensate for that by putting more bubble to one side.” This is done, Ng explains, by ejecting more gas toward the outside of the turn.


Naval officials say the high-speed torpedo will enable submarines to attack enemy subs and surface ships without giving them time to respond. The U.S. military has tested a prototype, but combat-ready versions are not expected for at least 15 years.
Link Posted: 1/4/2012 9:19:50 PM EDT
I know a guy who knows a guy. Let me know how many you need.
Link Posted: 1/4/2012 9:26:20 PM EDT
Originally Posted By www-glock19-com:

Originally Posted By WilliamGray:
They do not work worth a fuck in water with fluoride in it.

but the cavitation kills the germs that cause bad breath


We make holes in ship!
Link Posted: 1/4/2012 9:28:24 PM EDT
Nothing!
Link Posted: 1/4/2012 9:38:02 PM EDT

Originally Posted By BP03:
Russians have had one since the late 70's..

VA-111 Shkval

http://en.wikipedia.org/wiki/VA-111_Shkval

ETA: Supposedly the Iranians do too, called the Hoot, pretty much a knockoff of the Shkval

yup, its basically an underwater missile...
Link Posted: 1/4/2012 9:38:28 PM EDT
kaboom.
Ask the sailors on KURSK. oh, they're all dead.


they're underwater rockets, they're real and only the Russians could come up with something so batshit crazy.
Of limited use,very short range, but if used right, they could be very effective in certain circumstances, maybe. I guess.
Link Posted: 1/4/2012 9:40:10 PM EDT
[Last Edit: 1/4/2012 9:40:25 PM EDT by Alien]

Originally Posted By retgarr:
Within opsec of course, what can those of you in the know tell me about them?

I understand basically how they work, but would like to know more about them operationally..

Such as why don't we have any, what kind of threat are they, what is their downside, and what kind of defense is there against them.

I've seen bits about them and they sure seem damn scary.

Opsec? I don't believe it's a tech we use. What is there to worry about Opsec?

http://en.wikipedia.org/wiki/Supercavitation
Link Posted: 1/4/2012 10:56:53 PM EDT
Originally Posted By Alien:

Originally Posted By retgarr:
Within opsec of course, what can those of you in the know tell me about them?

I understand basically how they work, but would like to know more about them operationally..

Such as why don't we have any, what kind of threat are they, what is their downside, and what kind of defense is there against them.

I've seen bits about them and they sure seem damn scary.

Opsec? I don't believe it's a tech we use. What is there to worry about Opsec?

http://en.wikipedia.org/wiki/Supercavitation


Well I asked about how they affect operations. I'd say there is a point where that get's in to opsec. And I'm gonna guess that this is something we are checking out further too.
Link Posted: 1/4/2012 10:59:36 PM EDT
Originally Posted By Star_Scream:
I know a guy who knows a guy. Let me know how many you need.




Do you accept discreet Paypal?
Link Posted: 1/5/2012 12:09:09 AM EDT

Originally Posted By theBUBBAMANcan:
Originally Posted By Star_Scream:
I know a guy who knows a guy. Let me know how many you need.




Do you accept discreet Paypal?

Only USPS money orders since they are investigated by the FBI since they are federal docs.
Link Posted: 1/5/2012 4:07:04 PM EDT
Like Goddard, the genesis of the technology was developed here in the good ole USA, and the .gov promptly ignored it - just like Goddard. For the history of it look up Marshall Tulin and Phil Eisenberg.

Some of the technical hurdles include the aforementioned turning issue, but also the problem of supporting a body that is close to neutrally buoyant when submerged, but travels in an air bubble. Unfortunately, gravity still works underwater and supporting the torpedo becomes a problem.
Link Posted: 1/5/2012 4:25:24 PM EDT
Originally Posted By Keith_J:
Cavitation here is used for drag reduction. Now if the screw is in the rear, such flow regime would make the screw also cavitate. Forget rocket/mixed phase stream propulsion, too inefficient. The screw must be far behind the flow convergence, a long prop shaft works. Drag is limited by cross sectional area, skin friction is countered by the induced cavitation.

Downside? Range. They are thirsty beasts.


Forget rocket power?
Link Posted: 1/5/2012 4:28:05 PM EDT
Originally Posted By Seven-Shooter:

Originally Posted By Keith_J:
Cavitation here is used for drag reduction. Now if the screw is in the rear, such flow regime would make the screw also cavitate. Forget rocket/mixed phase stream propulsion, too inefficient. The screw must be far behind the flow convergence, a long prop shaft works. Drag is limited by cross sectional area, skin friction is countered by the induced cavitation.

Downside? Range. They are thirsty beasts.

Makes a helluva lotta sense. I wonder how long the prop shaft would have to be, and if it would fit in conventional sub tubes & still get range that's worth a damn.


No it doesn't. Look at the operational supercavitating torpedoes then look at his post. Also think about the real reason we don't have supercavitating torpedoes. To dothat look at the type of guidance our torpedoes use vs Russian torpedoes of the same vintage as the supercavitating torpedoes.
Link Posted: 1/5/2012 6:21:59 PM EDT
[Last Edit: 1/5/2012 6:26:26 PM EDT by 30Caliber]
It sounds like a 21" break-contact device; not a viable offensive weapons. It doesn't really matter how frickin' fast it goes. It's analogous to shooting a rifle at a target that you can't see and have only a vague idea of it's range and direction.

The platform (sub or ship) that fires one would also end up very very dead. Our torpedo doesn't rely on sheer luck; it's a bloodhound with a payload.
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