China's Blitzkrieg on U.S. Carrier

[gambit]

Readers,

Here are the facts...

Oxygen minimum zone - Wikipedia, the free encyclopedia

The Oxygen minimum zone (OMZ), sometimes referred to as the shadow zone, is the zone in which oxygen saturation in seawater in the ocean is at its lowest. This zone occurs at depths of about 200 to 1,000 metres, depending on local circumstances.

Acoustic Modem — Nortek AS

Shadow Zones A shadow zone is defined as a region with no direct path of acoustic energy, and only reflected energy may enter this zone. An acoustic shadow zone will occur if the speed of sound profile is not uniform; this will lead to bending of the transmission path or “rays”. A conceptual example is presented in the figure below. The trouble with shadow zones is that they can often exist with a mildly non-uniform speed of sound profile, and that they are usually non-stationary over time. This means that a location may have variable reception.

The word 'location' in the product blurb mean a sensor location.

SOSUS, beginning with Project Caesar back in the 1950s, were installing sensors from 200-something fathoms.

SOSUS The "Secret Weapon" of Undersea Surveillance

The first prototype of a full-size SOSUS installation – a 1,000-foot-long line array of 40 hydrophone elements in 240 fathoms of water – was deployed on the bottom off Eleuthera by a British cable layer in January 1952.

...And later sensors were going as deep as 1000 fathoms to avoid shadow zones and to exploit deep sound channels.

Here is the fathom to meters conversion...

Fathoms to Meters Conversion Calculator

So for the original SOSUS we have sensors in shadow zones in some areas and below the shadow zones in other areas. The issue is not detection but about accuracy and precision of those detection, which of course create a certain level of uncertainty. At worst, the sensor may not detect any surface noise generators at all because of these zones. But because the original SOSUS were placed at those depths, they were successful against subs because that was the intent -- submarine warfare. If surface ships cannot detect subs that are below the shadow zone, then neither can the sub nor any passive sensor that is below the shadow zone can detect any surface noise generators. The depth location of a shadow zone, as shown, are not constant. What we see in this debate is either the inability or deceitful refusal to connect these separate factors.

 

[Martian2]

For those of you who don't have your minds stuck in the Dark Ages, this is very simple.

49 years ago, the United States built passive sonar detectors to find Soviet submarines. The United States placed the detectors at the appropriate thermocline suitable for submarines. Using triangulation, the United States was able to determine the location of Soviet subs.

Today, China has a different use for passive sonar detectors. China wants to find the location of U.S. carriers and destroyers. China's task is immensely easier because 100,000 ton aircraft carriers are noisy as hell and nothing like extremely quiet nuclear powered submarines. China will place her hydrophones in the appropriate thermocline for surface ships.

Using the same principles of trigonometry that all of us learned in high school, China can triangulate and determine the position of U.S. carriers. You may not like the result, but too bad.

SOSUS Sosus System Ocean Atlantic Installed Sound Stations

"SOSUS, an acronym for SOund SUrveillance System, was a chain of underwater listening posts located for the most part across the northern Atlantic Ocean near Greenland, Iceland and the United Kingdom -- the so-called GIUK gap. It is operated by the US Navy originally with the purpose of tracking Soviet submarines, which would have had to pass through the gap in order to attack shipping in the Atlantic. A selection of sites in other locations in the Atlantic and Pacific Ocean have also had SOSUS stations installed.

SOSUS development was started by the Committee for Undersea Warfare in 1949, a panel formed by the U.S. Navy in order to further research into anti-submarine warfare. At the time the main concern was snorkeling diesel submarines, and the panel quickly decided that the solution was to use low-frequency sound detectors which would be able to hear the sound of their engines from hundreds of kilometres. Each site would consist of several detectors, allowing them to triangulate the position of the submarine. They recommended that $10 million be spent annually to develop such systems."

I'll let the other guy rant about oxygen levels or whatever he feels like.

 

[gambit]

For those of you who don't have your minds stuck in the Dark Ages, this is very simple.

49 years ago, the United States built passive sonar detectors to find Soviet submarines. The United States placed the detectors at the appropriate thermocline suitable for submarines. Using triangulation, the United States was able to determine the location of Soviet subs.

Today, China has a different use for passive sonar detectors. China wants to find the location of U.S. carriers and destroyers. China's task is immensely easier because 100,000 ton aircraft carriers are noisy as hell and nothing like extremely quiet nuclear powered submarines. China will place her hydrophones in the appropriate thermocline for surface ships.

Readers,

This is exactly what I am talking about -- making up 'facts' and violating the laws of physics.

Ship propellers generate low freqs from their rpm, usually at around 200-300, even for aircraft carriers. This translate to a blade freq of around 20hz and below. Human hearing range is 20-20khz. Low frequency sonar is within the same range and their maximum travel distance is...

Australian Whales, Dolphins and Porpoises - Sonar and seismic impacts

Low-frequency (LF). Low frequency sonars have been defined as those that emit sound below 1000 Hz. These sonars are designed to provide theatre level protection, such as for an Aircraft Carrier Task Group out to many miles (up to 200 miles) from the ships.

Ships are noise generators. A noise generator create an active sonar 'ping'. So if an active low freq sonar has a maximum distance of around 200 miles, how is it possible that the blade noise of an aircraft carrier can travel thousands of miles?

Chinese fanboy 'physics', of course...

Here are the real physics...

Sound Transmission in the Ocean - sea, depth, oceans, temperature, salt, system, wave, marine, salinity, Pacific

Specific combinations of temperature, pressure, and salinity may act to create shadow zones, or reflective layers, that are resistant to the propagation of sound waves.

So we have conditions where it is very possible that sound wave propagation does not exist, otherwise its origin is difficult to determine. Blade noise cannot exist if the ship is stationary. So if there are conditions where sound wave propagation is resisted, it would be even more difficult to determine the position of a moving ship.

A specific set of conditions, however, also act to create a channel through which sound waves propagate at minimal speed but with minimal loss of strength.

Now we getting somewhere...

...at a depth of approximately 750 meters (2,460 feet), the variations in temperature become so slight that the water becomes essentially isothermal (of uniform temperature). From that point, the speed of sound is regulated more by changes in pressure that accompany the increasing depth.

Because sound wave transmission speed is directly proportional to pressure, the speed of sound increases as the pressure increases with depth. Accordingly, at the interface of the thermocline and the isothermal depths, there exists a region of minimal speed of sound. This interface creates a sound "pipeline," or "deep sound channel," within the oceans that allows the transmission of low-frequency sound over thousands of kilometers.

Sound waves can be trapped effectively in the narrow SOFAR channel. Traveling at minimum velocity, the sound waves lose little energy, allowing the waves to propagate over distances in excess of 25,000 kilometers (15,500 miles).

Aah...So it is possible for low freq sound waves to travel thousands of km of distance. Except that somehow that sound wave must descend to 750 meters (2,460 feet).

Whoooppsss...

We have already seen that certain seawater condition can resist sound wave propagation and even stop it -- the shadow zone. So what we have here is a possibility, not a certainty, that the low freq blade noise of an aircraft carrier descends down to several hundreds meters to get trapped in a deep sound channel. And the ship is moving at that. Then we have another possibility, not a certainty, that this unique acoustic signature will pass upward through another shadow zone to be collected by a passive sensor.

Readers...This is Chinese fanboy 'physics'...

What happened is that people took the SOSUS capabilities, at its most general description, and apply it to a different environment. Low freq near surface propagation is nowhere the distance to make a passive sensor system effective.

 

[SinoIndusFriendship]

Take a look at the picture of the continental shelf. Arrays of hydrophones can be placed in water that is no deeper than 100m to avoid thermoclines. Or, if you're willing to spend the money, a country can place arrays of hydrophones at different depths along the continental slope. This approach would be similar to the placement of hydrophones at different depths by a group of U.S. destroyers with their towed array detectors.

To repeat, for those who do not understand, water that is 100m or less form essentially one layer. Arrays of hydrophones in 100m or less can avoid a thermocline and easily detect the sound of an aircraft carrier propeller.

I never claimed that it was easy. However, the physics is pretty straightforward. China has the sicentists, technology, money, and computer processing power to utilize a 49 year-old technology to find a "really huge" carrier propeller acoustic source. Why is that a big deal? It's a lot easier than building a sophisticated Aegis-class destroyer, which is NOT a 49 year-old technology.

Thermocline - Wikipedia, the free encyclopedia

"Waves mix the water near the surface layer and distribute heat to deeper water, such that the temperature may be relatively uniform for up to 100 m (300 ft), depending on wave strength and the existence of surface turbulence caused by currents. Below this mixed layer, however, the temperature remains relatively stable over day/night cycles. The temperature of the deep ocean drops gradually with depth."


"Graph showing a tropical ocean thermocline (depth vs. temperature). Note the rapid change between 100 and 200 meters."

Martian2 vs Gambit, Martian2 wins again!

 

[gambit]

Martian2 vs Gambit, Martian2 wins again!

If you have to resort to this level of self aggrandizement and make this declaration when the evidences are against your arguments, it mean you lost...

If near surface low freq sound propagation reaches thousands of km, then why did we place the SOSUS net sensors so deep? The answer is that near surface low freq sound propagation is nowhere like Chinese fanboy 'physics' would like to fool people.

 

[Martian2]

Propellers emit a wide range of noise levels over a spectrum. Noise data for the propellers of a Nimitz U.S. aircraft carrier is not available. The next best analog is a giant cruise ship. In the following article, you will learn that a cruise ship's propellers emit a broad range of frequencies and the spectrum changes depending on the speed or rpm (i.e. rotation per minute) of the propeller blades.

Powered by Google Docs

The paragraphs cannot be copied. Please read "3. Spectral Representation, 4. Volendam Signature, 5. Dominant Signature Components, and 6. Perspective" on pages 3 and 4.

A quick summary is that the large propellers of a cruise ship emit noise frequencies in a wide spectrum. The composition of high, mid, and low frequencies change depending on propeller speed. A Nimitz carrier propeller blades will behave similarly and emit a spectrum of high, mid, and low frequencies.

Here is the bottom line.

Using 49 year-old hydrophones, the United States could detect the tiny acoustic energy (e.g. look at the tiny wake) of a submarine and triangulate its location.



Using modern advanced hydrophones with far greater sensitivity, 49 years of technological improvements, and incomparable computer-processing power to identify the signal, someone is making the claim that this HUMONGOUS acoustic energy source cannot be detected within 300 Km to 600 Km of the modern advanced hydrophones and that triangulation is not possible. I think he's nuts.

 

[gambit]

Propellers emit a wide range of noise levels over a spectrum. Noise data for a Nimitz U.S. aircraft carrier is not available. The next best analog is a giant cruise ship. In the following article, you will learn that a cruise ship's propellers emit a broad range of frequencies and the spectrum changes depending on the speed or rpm (i.e. rotation per minute) of the propeller blades.

Powered by Google Docs

The paragraphs cannot be copied. Please read "3. Spectral Representation, 4. Volendam Signature, 5. Dominant Signature Components, and 6. Perspective" on pages 3 and 4.

A quick summary is that the large propellers of a cruise ship emit noise frequencies in a wide spectrum. The composition of high, mid, and low frequencies change depending on propeller speed. A Nimitz carrier propeller blades will behave similarly and emit a spectrum of high, mid, and low frequencies.

If you actually read your source, you would have seen the paragraph that said...

At 20 knots, low frequency propeller blade rate harmonics were present. One of these harmonics in combination with diesel generator energy caused the 25 Hz peak at 20 knots.

Which is within acceptable range for a ship that cruises at 30+ kts. It is these low freqs that has the longest range and distance is what we are talking about here.

Sonar - Wikipedia, the free encyclopedia

Long-range sonar uses low frequencies to minimise absorption effects.

So even if a ship generate freqs of several hundreds hz or even higher, it will be the lower freqs that will travels the furthest.

Here is the bottom line.

Using 49 year-old hydrophones, the United States could detect the tiny acoustic energy (e.g. look at the tiny wake and bubbles) of a submarine and triangulate its location.

Yes...But only if the sensors are located at several hundreds meters depth.

Using modern advanced hydrophones with far greater sensitivity, 49 years of technological improvements, and incomparable computer-processing power to identify the signal, someone is making the claim that this HUMONGOUS acoustic energy source cannot be detected within 300 Km to 600 Km of the modern advanced hydrophones and that triangulation is not possible. I think he's nuts.

Sorry...But somehow nature is not going to comply with your wishes.

 

[Martian2]

If you actually read your source, you would have seen the paragraph that said...


Which is within acceptable range for a ship that cruises at 30+ kts. It is these low freqs that has the longest range and distance is what we are talking about here.

Sonar - Wikipedia, the free encyclopedia

So even if a ship generate freqs of several hundreds hz or even higher, it will be the lower freqs that will travels the furthest.


Yes...But only if the sensors are located at several hundreds meters depth.


Sorry...But somehow nature is not going to comply with your wishes.

Do the math. 200 miles is equivalent to 333.33 Km. Adding the 350 Km from the location of the hydrophone array on the continental shelf to another 333.33 Km, while ignoring the sensitivity of modern advanced hydrophones, the base range is 683.33 Km or roughly 700 Km. That is the minimum distance that a carrier must stay away from the Chinese coast. That is still an effective deterrent.

 

[Martian2]

China's continental shelf varies. We will place the hydrophones as far out as possible. "The continental shelf between China and Japan is 325 nautical miles in width at maximum."

1 nautical mile = 1.852 kilometers

325 nautical miles x 1.852 Km/nautical mile = 601.9 Km

Low frequency sonar is effective out to 200 miles or 333.3 Km.

Total range of hydrophones is 601.9 Km + 333.3 Km = 935.2 Km

935.2 Km is pretty close to 1,000 Km. The range of 935.2 Km is an effective deterrent for China's ASBM.

 

[gambit]

Do the math. 200 miles is equivalent to 333.33 Km. Adding the 350 Km from the location of the hydrophone array on the continental shelf to another 333.33 Km, while ignoring the sensitivity of modern advanced hydrophones, the base range is 683.33 Km or roughly 700 Km. That is the minimum distance that a carrier must stay away from the Chinese coast. That is still an effective deterrent.

This is not about sensor sensitivity and you do not know how exact can China deploy those sensors. A Super Hornet's combat range is about 800km unrefueled. Over 1000km if it is configured for air-air. Looky here...You do not know what you are talking about. You did not know about the deep sound channels. You did not know about the shadow zones. You did not know about the SOSUS history. You did not know that sonar uses low freqs. And the list goes on...All of the things you did not know gave you a false sense of understanding of the subject.

 

[Martian2]

This is not about sensor sensitivity and you do not know how exact can China deploy those sensors. A Super Hornet's combat range is about 800km unrefueled. Over 1000km if it is configured for air-air. Looky here...You do not know what you are talking about. You did not know about the deep sound channels. You did not know about the shadow zones. You did not know about the SOSUS history. You did not know that sonar uses low freqs. And the list goes on...All of the things you did not know gave you a false sense of understanding of the subject.

I have no idea what you are complaining about now. I summarized that China's ASBM deterrent range is 935.2 Km from China's coast. All of the arguments in this thread regarding the serious dangers that China's ASBMs pose to U.S. capital ships are all relevant.

 

[SinoIndusFriendship]

I have no idea what you are complaining about now. I summarized that China's ASBM deterrent range is 935.2 Km from China's coast. All of the arguments in this thread regarding the serious dangers that China's ASBMs pose to U.S. capital ships are all relevant.

Gambit has met his match -- Gambit is no match for Martian2's consistent logical presentation of facts and reason! Burn baby burn!

 

[gambit]

I have no idea what you are complaining about now.

Of course not. Because am not 'complaining' about anything. I merely pointed out that you are ignorant of the subject. But you have no problems declaring yourself the winner of the debate despite those glaring ignorance.

I summarized that China's ASBM deterrent range is 935.2 Km from China's coast.

So what? It is a figure. But where is the threat?

All of the arguments in this thread regarding the serious dangers that China's ASBMs pose to U.S. capital ships are all relevant.

Of course...If the threat exist.

 

[gambit]

Gambit has met his match -- Gambit is no match for Martian2's consistent logical presentation of facts and reason! Burn baby burn!

Aah...So you admit you are no match for me...

 

[Martian2]

This idea is going to sound radical, so hold on to your hats. In the event of a declaration of independence by a hypothetical loose-cannon DPP Taiwan president, what if China chose to strangle Taiwan economically without the need for ASBMs, anti-ship missiles, or submarines to enforce an embargo?

However, this would be irrelevant because they would be unable to stop a blockade of Taiwan anyways. All China would need to do is publicaly declare that any commercial ship intending to dock in Taiwan would be attacked by missiles. In such an environment, no non-military vessel would dare take the risk. Besides that, the docking facilities would probably be destroyed as well, so even without a missile threat, ships wouldn't be able to unload/load their cargo anyways.

The idea of destroying Taiwan's docking facilities is an ingenious way to achieve an embargo. There would be no need to blockade Taiwan with submarines. Destroy the docks and Taiwan would eventually beg China for a settlement. I guess Taiwan can't declare independence if it wants to survive economically.

By the way, the idea of destroying docks for unloading ships, is this your original idea? Unfortunately, it never occurred to me and this is the first time that I've heard of the idea. Taiwan is particularly susceptible to an embargo; however it is achieved.

http://www.businessweek.com/news/2010-05-1...s-update1-.html

"Wednesday May 19, 2010

Bloomberg
Taiwan’s Economy May Have Expanded Most in 20 Years (Update1)
May 19, 2010, 12:06 AM EDT
...
The recovery also brought an exit from deflation, with consumer prices rising 1.3 percent in April, a fourth consecutive increase. Crude-oil prices have risen about 20 percent in the past 12 months, boosting transport costs in Taiwan, which imports 99 percent of its energy. Central bank Governor Perng Fai-nan said two months ago the bank won’t sacrifice price stability for economic growth."

I thought about it while I was writing it. It took me maybe 10 seconds to think of it because it's so obvious. Taiwan cannot be directly attacked simply because China does not have the capability. It does not have enough landing craft to land the 50000+ fully equipped soldiers it would need for the first wave. Anything less than this would be cut down at the beachhead because Taiwan's military numbers in the hundreds of thousands and they would have advance warning before the actual assault.

The only way to bring Taiwan to its knees is economic blockade, to starve Taiwan. Without the fuel and food to sustain Taiwan, it would literally fall apart in a few months. China does not want to kill anybody on Taiwan. Their declared aim is to reunite peacefully with their fellow countrymen. However, if another Chen Shui-bian comes to power and is covertly backed by the U.S., I'm sure something along the lines of what I said will happen. There is absolutely no defense against that. China would probably bomb every airport, military and commercial, every port...military and commercial. Basically, every transportation conduit while leaving the rest of the infrastructure intact.

Taiwan would be forced to negotiate within 6 months or risk utter destruction. If it escalated with U.S. tit-for-tat intervention, China could sustain much more damage simply because it has continental scale whereas Taiwan is a comparatively small island with few natural resources. It's really a no-brainer, Taiwan would lose big time and has 0% chance of success.