PLAN sub appears close to the USS Kitty Hawk again?

China and US both side official still no reply for this event.
interesting thing is 2 days ago China refuse US carrier Kitty Hawk visit Hong Kong because PLA was holding Military exercises in south China sea.
but one chines official internet < Peoples Net> Publishing an article refuting the report,the points are below:

First, during peacetime, the Navy will not take the initiative to send single-submarine tracking the aircraft carrier formation of another country, but also in the formation surfaced before, this eye-catching practice will be done only fools.

Weak defense aircraft carrier itself, is carrying operational aircraft platform. The United States dispatched the aircraft carrier will have more than 10 warships counterparts, including air defense cruisers, destroyers anti-ship, anti-submarine submarines and 1 ~ 2 logistic supply ship, the aircraft carrier constitute a tight protective net. During the exercise period, the aircraft carrier will continue to send anti-submarine aircraft and other early warning aircraft patrolling the airspace around.

Second, the U.S. and other countries have fixed the exercise or training area, the majority of cases open briefing exercise time, inform the countries concerned in a specific time carefully through these waters, it is international practice. The navy of another State, in that exercise is that the circumstances, the vessel formation is often bypassed exercise training area.

Third, although a previous agreement, the two sides Navy do not take the initiative to each other provocative moves. In January 1998, the United States signed the "on the establishment of the maritime military security consultation mechanism in the Agreement," and this is the first between the two countries military confidence-building measures in the Agreement.

Thus, whether from the Navy customary practices and international practice, or Sino-US military prior agreement, China dispatched ships to the United States aircraft carrier is not tracking any significance, the two sides will only provoke mistrust and tension in relations , will be "Chinese submarine threat theory" advocates that provide the basis for the matter. ☆

Over the past year, high level military officials in China and the US have met, and among the results of such meetings are a series of protocols to make sure events like that of November 2006 won't happen again. They would probably inform each other of their own respective exercises and set boundaries to make sure there won't be any mistakes.

Having said so, the PLAN and the USN/JSMDF were conducting exercises right at the same time, with the USN using the Kitty Hawk and escorts. The PLAN exercise was a major one, as it included at least one major destroyer, the 168, along with Jiangweis, Jianghus and Ludas, but also Houbeis and JH-7As, all involved in various forms of live fire. The PLAN also conducted ASW type exercises trying to defend themselves against PLAN subs playing aggressor. It should be noted that one PLAN sub of the East Seas fleet (could be Kilo but likely a Song) was commended for penetrating the ASW screens. All these happened just a week ago or the first half of this month.

Chinese submarines probably can't consistently stalk American carriers unless...

A-- They bought that capability from the Russians. The only boats that the Chinese navy could really use to stock up carrier group would have to be either an Akula or Sierra II recently bought from the Russians. Needless to say the Russians would be hesitant to sell the best of their submarine technology. It's more likely that they sold the Chinese an earlier class, such as the Victor III. Unfortunately the Victor III would be an extreme long shot for stalking a modern American carrier group, due to its noise output.

Or

B--- Of the diesel electric submarines that could sneak up on a carrier group, a wider menu appears. However these types of boats require that the Chinese navy know when and where an American carrier group would be before they get there. Charging one's batteries on the surface is a great way to be detected for many miles around. So such a diesel electric would have to sit on the bottom waiting for a carrier group along its expected patrol path. If this is what happened, the Chinese have very likely have broken United States Naval communications ciphers. Additionally using a diesel submarine in this fashion might require a portion of the ocean well within the continental shelf, so a diesel could actually sit on the bottom conserving battery power.

Given the difficulties with both A and B, it's more likely that option C was used instead. Options C is the story was recycled from an earlier incident which would explain the silence of the press on this issue.

the Chinese have very likely have broken United States Naval communications ciphers

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I doubt this. Simply put the US changes it's various codes, shall I say, frequently.

First of all, China does not buy Akula, Sierra or Victor. They have their own nuclear subs. I think the 093 Shang is much quieter than the 091 Han, and the 091 Hans have now been "improved" to be more quiet as well. But my impression is that nuclear subs, even the latest ones have not overtaken the advances in passive sonar detection, which is now boosted by COTS electronics and advanced software algorhythms.

Second, the exercises always seems to occur in the same general areas or ocean corridors, and it is not as if the USN and JSMDF would announce them to the public in order to keep civilian ships off. This kind of knowledge is easily obtained, so you would knkow where they would be exercising at. Of course this would be totally useless in wartime.

Third, stalking is a fairly common practice, you just don't stalk too close or get caught doing it, and you don't do it within the designated areas of the exercise, so the stalkers can be expected just outside the boundaries. You are free to do whatever you want in international waters after all. Usually the purpose is just to observe, collect data or signatures. In fact, you should expected to get "observed" in any exercise, that is just part of the game. The activity is routine enough it does not warrant mentioning it.

bd popeye said:

I doubt this. Simply put the US changes it's various codes, shall I say, frequently.

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Hahahahah that it certainly does. Unfortunately and occasionally espionage allows one to read ciphers one does not have the key for. The Russian Akula class submarine for example (which I mentioned in a previous post), came about largely due to the espionage activities of John Walker Lindh. US sailors to this day still refer to the accrual as the "Walker class".

Linda's also gave the Soviets so many codebooks throughout the latter part of the 70s the Russians were able to read our future codes, up until the time the cipher itself was updated to a completely new version. After Linda's was captured and convicted the USN had to come up with a completely new cipher key methodology. ( to say nothing of beefing up policy with regards to handling and disposing of "crypto's" on U.S. Navy ships)

Just because you change the cipher keys often does not ensure security if your opponent knows enough about the precise algorithms used to generate the key itself. It's always been a universal law of nature, that it's easier to destroy than to create... And that law sadly applies just as much to cryptography as almost everything else.

crobato said:

First of all, China does not buy Akula, Sierra or Victor. They have their own nuclear subs. I think the 093 Shang is much quieter than the 091 Han, and the 091 Hans have now been "improved" to be more quiet as well. But my impression is that nuclear subs, even the latest ones have not overtaken the advances in passive sonar detection, which is now boosted by COTS electronics and advanced software algorhythms.

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The fact that passive sonar detection has not only kept pace with quieting but outstripped it tends to enhance my original point.

Second, the exercises always seems to occur in the same general areas or ocean corridors, and it is not as if the USN and JSMDF would announce them to the public in order to keep civilian ships off. This kind of knowledge is easily obtained, so you would knkow where they would be exercising at. Of course this would be totally useless in wartime.

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Thanks for mentioning this point because I had not fully thought out the fact that exercise ranges on the open ocean might be quite standardized, known by all. In that case cryptographic data would not be needed to find a precise time and place. Just go with the exercises have been held before.

Third, stalking is a fairly common practice, you just don't stalk too close or get caught doing it, and you don't do it within the designated areas of the exercise, so the stalkers can be expected just outside the boundaries. You are free to do whatever you want in international waters after all. Usually the purpose is just to observe, collect data or signatures. In fact, you should expected to get "observed" in any exercise, that is just part of the game. The activity is routine enough it does not warrant mentioning it.

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It's only mentioned in this case was the Chinese sub was able to get so very close before detection was made. Nevertheless the story is likely over a year old and recycled, as revealed in previous posts. The USN might have beefed up its ASW detection doctrine and training in response to this incident. Hopefully somebody in this form can find an article that points to evidence of this, because my own research has come up empty.

You generate your keys with a mersenne twister and seed it with what you had for breakfast. You'll be fine...

Raptoreyes said:

The fact that passive sonar detection has not only kept pace with quieting but outstripped it tends to enhance my original point.

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For nuclear subs that is. For conventional subs however, it is more of a serious problem because diesel submarines have far less moving parts, and tend to work in the part of the ocean that is not just noisier for the ship traffic, but sound travels much less. Especially in the warmer waters of the Pacific.

It's only mentioned in this case was the Chinese sub was able to get so very close before detection was made. Nevertheless the story is likely over a year old and recycled, as revealed in previous posts. The USN might have beefed up its ASW detection doctrine and training in response to this incident. Hopefully somebody in this form can find an article that points to evidence of this, because my own research has come up empty.

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The last year story goes the sub was not detected at all. As a matter of fact, according to the CSR report on the PLAN 2007 which I have a copy in PDF, the sub also "disappeared" after it surfaced, eluding all attempts to track it after it surfaced.

Of course in peacetime, people prefer to use passive sonar because it does not advertise your location, and it is "green friendly". But in wartime, it is expected that escorts would be using active sonar, which no quieting measure has a complete defense, although the drawback is that it gives your position away. The problem is during exercises, we tend to avoid using active sonar because it beaches whales, and the environmentalists will have a field day. This lessens the "quality" time you can put into the practice of active sonar. Another problem is the USN dogma not to make or own any diesel submarine at all. Thus unlike the USAF, you don't have dissimilar combat training with specialized aggressor forces. Instead of keeping a local fleet of diesel subs used for aggressor purposes, the USN has to either lease a foreign sub (Sweden) or conduct exercises with countries that have diesel subs (Peru, Chile, Australia, Japan, Greece, South Africa, India, Japan, Germany, Canada, among them).

crobato said:

But in wartime, it is expected that escorts would be using active sonar, which no quieting measure has a complete defense, although the drawback is that it gives your position away.

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It is true that your active sonar will give you away, but to get around that you work in groups, with one platform for pinging, and the other lying in wait either wait for the enemy to reveal themselves or actually pursuing the enemy as revealed by the active sonar.

Finn McCool said:

It is true that your active sonar will give you away, but to get around that you work in groups, with one platform for pinging, and the other lying in wait either wait for the enemy to reveal themselves or actually pursuing the enemy as revealed by the active sonar.

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The caveat to this is that you will have a smaller perimeter of detection.