Detection of Submarines

Chinese researchers find novel method to track US submarines

"Researcher Zou Shengnan and her team were looking at the possibility of detecting almost imperceptible bubbles made by the submarine as it cruises through water and has now successfully generated a computer model to demonstrate that it could potentially work.

Submarines cannot avoid these bubbles as their motion causes the water around the hull to move faster, reducing its potential energy. The potential energy is expressed as pressure and as it decreases, some of the water vaporizes to maintain the energy equilibrium.

This process occurs more in areas of sharp curvature or where the surface is rough, and as water flows around the hull, the bubbles get bigger and move away from the surface. Here the higher pressure causes them to collapse violently, resulting in an electromagnetic signature, a phenomenon known as the magnetohydrodynamic (MHD) effect."

See:

interestingengineering.com

Chinese researchers find novel method to track US submarines

Known for their stealth, US submarines could lose their advantage after further research in this area.
interestingengineering.com interestingengineering.com
 
How the Navy Tried to Turn Bioluminescence Against the Soviets

"For decades, during the Cold War, both the U.S. and the U.S.S.R. had a military interest in bioluminescent organisms, which use a chemical reaction to produce a brief glow when they’re stimulated. The light of tiny ocean creatures had revealed on occasion the locations of submarines in World War I, and both militaries imagined that they might be able to use this natural phenomenon more systematically in anti-submarine warfare."

See:

www.atlasobscura.com

How the Navy Tried to Turn Bioluminescence Against the Soviets

They spent decades on it.
www.atlasobscura.com www.atlasobscura.com

&

 
dumpster4 said:
Chinese researchers find novel method to track US submarines

"Researcher Zou Shengnan and her team were looking at the possibility of detecting almost imperceptible bubbles made by the submarine as it cruises through water and has now successfully generated a computer model to demonstrate that it could potentially work.

Submarines cannot avoid these bubbles as their motion causes the water around the hull to move faster, reducing its potential energy. The potential energy is expressed as pressure and as it decreases, some of the water vaporizes to maintain the energy equilibrium.

This process occurs more in areas of sharp curvature or where the surface is rough, and as water flows around the hull, the bubbles get bigger and move away from the surface. Here the higher pressure causes them to collapse violently, resulting in an electromagnetic signature, a phenomenon known as the magnetohydrodynamic (MHD) effect."

See:

interestingengineering.com

Chinese researchers find novel method to track US submarines

Known for their stealth, US submarines could lose their advantage after further research in this area.
interestingengineering.com interestingengineering.com
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Tiny bubbles, In the wine
Make me happy, Make me feel fine
Tiny bubbles, Make me warm all over
 
Non acoustic detection of submarines from aircraft or satellites has been the holy grail for decades. Numerous avenues have been investigated. I do not rule out the possibility, but on the other hand the topic seems very much to mirror energy producing fusion: someone always has a brighter idea, and its always just around the corner.
 
As a submarine has neutral bouyancy it has the same density as seawater. Surely that rules out gravimetric detectors
 
www.oceansciencetechnology.com

ELWAVE Showcases Tetrapulse Sensor at Coastal Trident 2024 - Ocean Science & Technology

ELWAVE recently demonstrated its Tetrapulse sensor at the ANTX Coastal Trident 2024 exercise, organized by the US Navy. Throughout the...
www.oceansciencetechnology.com www.oceansciencetechnology.com

The Tetrapulse, a compact subsea electric sensor, excels in real-time electrical impedance measurements, making it highly effective for identifying targets in turbid waters.

The sensor leverages ELWAVE’s CEDAR technology, inspired by the sensory systems of tropical freshwater fish. With its modular design and up to four electrodes, Tetrapulse can be equipped with cables ranging from 1.5 to 7 meters, suitable for various underwater vehicles and fixed-site installations.

Tetrapulse offers precise detection, localization, and classification of both metallic and non-metallic objects, including those buried at depths of 1 to 2 meters. Rated for depths up to 300 meters, it performs reliably in both water and air, even in noisy environments.
Click to expand...

View: https://www.youtube.com/watch?v=fR3pvT-CpC4
 
OliverSedlacek said:
As a submarine has neutral bouyancy it has the same density as seawater. Surely that rules out gravimetric detectors
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I would not be so certain.

Sufficiently-sensitive sensors might be able to detect the difference between the very dense reactor(s) and/or battery packs and the less-dense inside of the hull.

I'm certain various groups are pushing for sensors like that, for projects that depend on finding dense/heavy things at a distance. Mining, archaeology, military...



Forest Green said:
www.oceansciencetechnology.com

ELWAVE Showcases Tetrapulse Sensor at Coastal Trident 2024 - Ocean Science & Technology

ELWAVE recently demonstrated its Tetrapulse sensor at the ANTX Coastal Trident 2024 exercise, organized by the US Navy. Throughout the...
www.oceansciencetechnology.com www.oceansciencetechnology.com
Click to expand...
That looks more like a very short-ranged sensor, they're talking about turbid (cloudy) water and IDing things like mines and artillery shells.

I'm not sure how far you could stretch that sensor range, I'd be surprised if it was good for more than a couple dozen meters without an immense number of wire wraps for signal amplification. I've seen an example induction coil with something like 200,000 wraps of wire that has a decent range (100m).
 
The U.S. is designing a new CAPTOR mine. Initially it will use a mk54, but I think it is only a matter of time until a CRAW version is built - you could get three light weight torpedos in for the mass of one standard air dropped fish.
 
Josh_TN said:
The U.S. is designing a new CAPTOR mine. Initially it will use a mk54, but I think it is only a matter of time until a CRAW version is built - you could get three light weight torpedos in for the mass of one standard air dropped fish.
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Whereas I'm expecting bigger torpedoes wanted/needed. Basically a return to Mk37s for the "lightweight" air dropped fish, some 1500lbs.
 
Scott Kenny said:
Whereas I'm expecting bigger torpedoes wanted/needed. Basically a return to Mk37s for the "lightweight" air dropped fish, some 1500lbs.
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Why? Even if your target is a surface ship, a mk54 will send it home, if not to the bottom. Not that I am aware of mk54 having an anti surface mode.
 
Josh_TN said:
Why? Even if your target is a surface ship, a mk54 will send it home, if not to the bottom. Not that I am aware of mk54 having an anti surface mode.
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Because Mk54s versus submarines is really kinda marginal. Virginias are, and the Super-Seawolfs will be able to, accelerate fast enough that you'll exhaust the Mk54 before it catches you.

Heavyweight torps are really good at breaking surface ships in half, but the warhead in a Mk54 is barely big enough to pop shaft seals. I suspect that a military surface ship with popped shaft seals would be able to keep up with the water ingress and would likely not even slow down.
 
A lot of the detection process today revolves around databases of known sounds and processing capacity. This is much of the reason you can infer that the US Navy, as an example, has been moving away from specialist ASW aircraft and ship platforms. Instead, large sound sensor arrays coupled to powerful computers simply analyze every sound in the ocean filtering out background noise to find things of interest.
 
Scott Kenny said:
Because Mk54s versus submarines is really kinda marginal. Virginias are, and the Super-Seawolfs will be able to, accelerate fast enough that you'll exhaust the Mk54 before it catches you.

Heavyweight torps are really good at breaking surface ships in half, but the warhead in a Mk54 is barely big enough to pop shaft seals. I suspect that a military surface ship with popped shaft seals would be able to keep up with the water ingress and would likely not even slow down.
Click to expand...

A mine likely activates at sufficiently short enough range that the mk54 should not have a big problem catching any target, and certainly D/Es have no hope of out running it. CRAW would have the advantage of an even more rapid acceleration, and while the damage may not be fatal, you boat is still going to a body shop. If the HEAT warhead gets a favorable angle and breaches the pressure hull, seems doubtful anything goes home that isn’t double hulled.

As for surface ships, I have a hard time believing 100 lbs of PBX does not slow a ship down. USS Tripoli was immobilized by 300 lbs mine exploding at a sub optimal position due to the ship pivoting across the mine rather than running over it front to back.
 

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