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That's why it could be a bit noisy when it sails over 30 knots, it is common for every other SSNs.

BTW, the Type 095 could sail silently at 20 knots.

That is true. Going over 20 knots is noisy and is only used for transitions, e.g. going from base to the patrol area or going from one patrol area to another patrol area.

Even if they managed to make a totally silent propulsion system, making noise is unavoidable when going over 20 knots because of hydrodynamic noise (noise produced from water flowing pass the hull). So when an enemy sub is sitting still waiting for ambush, your sonar will pick up more noise from your own sub than the enemy sub.

From what I've read, patrolling speed during peace time is restricted to 10-20knots. Patrolling during state of war or when an unwelcome guest is suspected, speed is restricted to 8-10knots. When in hostile environment or in hunting-killing mode, it's under 6knots.
 
The Type 093 could sail faster than the Type 054A.
Not could but it does. SSN is always faster than surface fleet in top speed everywhere. But with speed its accuracy is diminished significantly. Although speed is still on its side.

That is true. Going over 20 knots is noisy and is only used for transitions, e.g. going from base to the patrol area or going from one patrol area to another patrol area.

Even if they managed to make a totally silent propulsion system, making noise is unavoidable when going over 20 knots because of hydrodynamic noise (noise produced from water flowing pass the hull). So when an enemy sub is sitting still waiting for ambush, your sonar will pick up more noise from your own sub than the enemy sub.

From what I've read, patrolling speed during peace time is restricted to 10-20knots. Patrolling during state of war or when an unwelcome guest is suspected, speed is restricted to 8-10knots. When in hostile environment or in hunting-killing mode, it's under 6knots.
A nuke sub doesn't go that slow as it will get trapped in ambush if it slows down to that lecel. SSN is way different than a ssk. If a SSK is lurking in deep water, SSN best advantage is its constant high speed. If it slows down Ssk will hunt it down. As a SSN is always noisy compare to modern SSKs.
 
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A nuke sub doesn't go that slow as it will get trapped in ambush if it slows down to that lecel. SSN is way different than a ssk. If a SSK is lurking in deep water, SSN best advantage is its constant high speed. If it slows down Ssk will hunt it down. As a SSN is always noisy compare to modern SSKs.

Oh yes they do my friend, they do go slow (same speed range as a SSK, I. e. below 20knots) when on patrol. SSN rarely go over 20knots (or full speed) except for when transitioning to the patrol zone. Another situation when they go over 20knots is when escorting a surface fleet, where the surface vessels are going over 20knots for example.

I don't know what advantage you have in mind when saying that SSN is faster than SSK. Especially in patrolling or escorting scenario. Did you mean that a SSN can constantly go fast so the slower SSK can never hope to catch up to attack it? or that a SSN can go full speed and outrun a SSK when detected?

That's not the purpose of a patrol. If an enemy sub is detected, the SSN need to hunt it down, identify it and destroy it, not running away. If an enemy sub coordinate an ambush well and positioned itself right, it will be hard for a SSN running at over 20knots to detect it especially when the SSK is loitering slowly on batteries or AIP. That's why a Chinese sub managed to sneak within close range of a US carrier fleet years ago. Like you said, the SSK in slow speed would be more silent than the SSN. And once in torpedo range of the SSK, the SSN can never outrun the torpedo even if the SSN can go over 35knots. So I'm not sure what you mean by saying that SSN has its advantage in its speed.

Modern SSK are capable of going over 20knots.The max 20knots speed is self-imposed by the manufacturer because there's no much point for SSK to go over 20Knots. Transitioning to far away patrol zone or escorting a surface fleet is the two scenario where going over 20knots is needed but SSK don't have the endurance to patrol far from Base like SSN or to escorts surface fleets.
 
Oh yes they do my friend, they do go slow (same speed range as a SSK, I. e. below 20knots) when on patrol. SSN rarely go over 20knots (or full speed) except for when transitioning to the patrol zone. Another situation when they go over 20knots is when escorting a surface fleet, where the surface vessels are going over 20knots for example.

I don't know what advantage you have in mind when saying that SSN is faster than SSK. Especially in patrolling or escorting scenario. Did you mean that a SSN can constantly go fast so the slower SSK can never hope to catch up to attack it? or that a SSN can go full speed and outrun a SSK when detected?

That's not the purpose of a patrol. If an enemy sub is detected, the SSN need to hunt it down, identify it and destroy it, not running away. If an enemy sub coordinate an ambush well and positioned itself right, it will be hard for a SSN running at over 20knots to detect it especially when the SSK is loitering slowly on batiteries or AIP. That's why a Chinese sub managed to sneak within close range of a US carrier fleet years ago. Like you said, the SSK in slow speed would be more silent than the SSN. And once in torpedo range of the SSK, the SSN can never outrun the torpedo even if the SSN can go over 35knots. So I'm not sure what you mean by saying that SSN has its advantage in its speed.

Modern SSK are capable of going over 20knots.The max 20knots speed is self-imposed by the manufacturer because there's no much point for SSK to go over 20Knots. Transitioning to far away patrol zone or escorting a surface fleet is the two scenario where going over 20knots is needed but SSK don't have the endurance to patrol far from Base like SSN or to escorts surface fleets.
Friend you do need to update your knowledge a bit. 2nd and 3rd generation SSNs had to run around 6 knots because they were pretty noisy back then. After pumpjet propulsion system 4th gen nuke boat doesn't need to care much about a SSk as was the situation against them some time back. And when you are claiming the 20 knots speed for SSK, it will be suicidal run for it as they don't have the required resources for it. And what do you mean by rarely operating over 20 knots. I don't get it. Regarding ssn vs ssk fight, when I say higher speed, i mean survivability and outmaneuvering. A SSN biggest advantage is high speed because due to this only even if a ssk detects it first it can get behind the ssk much easily. And don't forget that even though Ssn is noisy than a ssk but its SoNAr and intelligence gathering is also pretty strong backed by abundent nuke power. And why not to run away at faster speed if your position has been compromised. If you stay longer more suicidal it will become. And mind it that was not only Chinese ssk which penetrated surface force screen, there have been multiple encounters and exercises where ssks have scored hit against a carrier. Surface fleet is always at disadvantage against a sub surface fleet. Period. When on patrols nuke subs are always on high level attention which means even if a ssk detects a ssn, they don't have much chance against it. If those ssks try to coordinate they will give away their position easily. They will lose their most important weapon, their stealth.
 
Friend you do need to update your knowledge a bit. 2nd and 3rd generation SSNs had to run around 6 knots because they were pretty noisy back then. After pumpjet propulsion system 4th gen nuke boat doesn't need to care much about a SSk as was the situation against them some time back.

Friend, now you're changing the subject matter from a SSN to a "pump-jet propulsion SSN." Not all SSNs currently operated by every navy have pump-jet propulsion. Does your recently leased Akula use pump-jet? am I correct that your Akula 's quiet mode/tactical speed is still only around 6 knots (even with the OK-300s)??

Yasen class SSN does not have pump-jet, and I thought they are fourth generation nuke sub? If I remember correctly, Yasen tactical speed is well below 15knots. So they definitely patrol or hunt below 15knots.

If you think pumpjet SSN doesn't need to care much about SSK anymore, then you should write to the US naval war college and tell them to revoke their article:

Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

https://www.usnwc.edu/getattachment...RIGHT-SUBMARINE-FOR-LURKING-IN-THE-LITTO.aspx

But even if we are only talking about pump-jet SSNs, I still don't believe that they would hunt for SSKs at over 20knots. I know that some US official claim that their Seawolf's tactical speed is 25knots, and then some BAE pr guy said their Astute can atleast match the tactical speed of the best US SSN. But when we're talking about these SSN vs modern SSKs, they won't operate at these kind of speed. (and I think comparing SSN vs SSK is relevant here, since the opponents of Chinese SSNs most likely SSKs from Japan, Vietnam, Taiwan and most likely opponent of Indian SSNs are Pak's SSK).

The reason I said they won't go over 20knots when hunting suspected enemy SSKs is because of the flow/hydrodynamic noise from the hull or the sonar array. Yes, pump-jet decreases cavitational noise and flow noise over traditional propellars dramatically but it can't help much in reducing the flow noise going across the hull and sonar array. This mean the passive sonar from enemy sub has a chance to detect this noise. But more importantly, the noise from water flowing over the array sonar can interfere or reduce its sensitivity. The flow noise from the hull can likewise compromise its hull mounted passive sonar.

Self-noise [SN] comes from the noise from the platform the sonar is on or from the flow of water across the receiving array itself. This self-noise has a minimum value which is present regardless of the speed that the array is traveling through the water, and the self noise will increase due to flow noise and the increase in noise from the platform which carries it. Self noise has a frequency and speed dependence.

Now since the flow noise increases in proportionate to speed, the SSN would need to slow down in order to increase the sensitivity of its sonars. Now, you may be right in saying that american SSNs has powerful sonars, but I highly doubt it can detect modern SSKs when going over 20knots. When modern SSKs are loittering around at under 4knots on batteries/AIP or sitting still in ambush position, they are almost silent. They pratically won't produce any flow noise or any other self-noise. The only sonar can detect them is the active sonar and the SSN would need to slow down to make the most out of it. (I have an article somewhere on my PC which explain how the current sonars that the US have in operation have difficulties in detecting modern SSK and now they are developing UUVs to solve this problem, I can link it when I have time to find it).

And if we consider the environment where enemy SSKs are most likely to operate in (near coast or littoral area), it is extremely hard for SSN to detect them. That article from naval war college explains it well.

So yes, top SSNs with pumpjet propulsion may have tactical speed over 20knots, but this speed only mean the top speed that the SSN can go undetected (supposedly). But to detect enemy SSK, this speed will need to be reduced in order to make the most out of its sonars. So when when enemy sub are suspected to be in the patrol zone or when hunting for them, its speed is decreased. This is what I mean.

And when you are claiming the 20 knots speed for SSK, it will be suicidal run for it as they don't have the required resources for it.

Most modern SSKs like the U214/212 or Scorpene can sustain a speed of 20knots for a few hours if I remember correctly. These are burst speed used in rarely situation only (maybe in a sub on sub fight or manouvre like you mentioned?).

And what do you mean by rarely operating over 20 knots. I don't get it. Regarding ssn vs ssk fight, when I say higher speed, i mean survivability and outmaneuvering.

Meaning its for certain maneuvering in certain situation only, or for transitioning when encounter with enemy subs are not expected. Like I mentioned before, they have different speed for different situation like patrolling during peace time, patrolling in hostile environment or hunting mode, etc (btw, the speeds I gave previously are for PLAN subs that I've read). Different navy may use different speed to due their different SSNs characteristic or doctrine. I suspect the Russian navy will have similar figures but I may be wrong.

A SSN biggest advantage is high speed because due to this only even if a ssk detects it first it can get behind the ssk much easily. And don't forget that even though Ssn is noisy than a ssk but its SoNAr and intelligence gathering is also pretty strong backed by abundent nuke power.

Yes this is true. But I don't agree this is going to be the case when going up against a SSK sitting still in ambush position in a littoral environment (and this is the most likely scenario that a PLAN or Indian SSN can face). But in these cases, PLAN and Indian's SSKs will be deployed to patrol these littoral area, not SSNs. If the SSNs were deployed, they will still be at a disadvantaged like what the article say:

Because of the short distances, high
sustained speed for a submarine is
not as critical a factor as it is in the
open ocean. In shallow water, a fast-
moving sub would have little time to
take corrective action should anything
go wrong. The proximity of the seabed
creates an area of reduced pressure,
called the squat (suction), under the
keel.This can lead to handling difficulties and even grounding.

And I seriously doubt PLAN and Indian's SSN will be challenged in the open ocean (blue water). Maybe the Japanese Soryu SSK with its relatively long endurance.

And why not to run away at faster speed if your position has been compromised. If you stay longer more suicidal it will become.

If you're on a solo patrol, then yes. But a SSN on an escort mission would not just simply run away, especially if the SSK is only targetting the surface fleet and not the SSN itself.

And mind it that was not only Chinese ssk which penetrated surface force screen, there have been multiple encounters and exercises where ssks have scored hit against a carrier. Surface fleet is always at disadvantage against a sub surface fleet. Period.

True.

When on patrols nuke subs are always on high level attention which means even if a ssk detects a ssn, they don't have much chance against it. If those ssks try to coordinate they will give away their position easily. They will lose their most important weapon, their stealth.

What I meant by coordinate was that a SSK would predict the coordinate that a SSN/surface fleet would pass by (with coordination and assistance from airpatrol craft, surface ships, satelite, etc.) and sit still in ambush position or loittering slowing on batteries/AIP. In this situation, the SSN is at an disadvantage in detecting the SSK. And if the SSN/surface fleet enter within the SSK torpedo range, they are in trouble.

But we are getting off topic in this thread. So I'll try say something relevant instead:

A little bird once told me that the PLAN will phase out all of their SSKs in the future. They will only be for the export market. To deal with the littoral/coastal area and where SSKs has an advantage, they're developing UUVs that works in coordination with the SSN. The silent and fast UUVs equiped with sonar will go out and scan for enemy subs or mines. The SSN would play a role of cammand and control center. The US is also developing this. They've already managed to developed battery operated UUV with endurace of over 1 month. The future is UUVs.
 
Chinese Type 035G submarine.

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Type 041 Yuan SSK with AIP

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Chinese Type 041 Yuan diesel-electric submarine with AIP (ie. air independent propulsion)


There are currently about 13 Yuan-class conventional attack submarines.[1] The Yuan SSK has many improved features.[2]

a. advanced high-frequency sonar
b. upgraded weapons systems
c. noise reduction[3][4]
d. air independent propulsion (AIP) allows a submarine to stay submerged for about three weeks
e. "This new sail design may incorporate an additional high-frequency sonar at the base of the sail, as do some other submarines with similar designs."
----------

Citations.

1. China Submarine Capabilities | NTI
"The PLAN also possesses around 13 Type 039 Song and twelve Type 041 Yuan-class submarines, which are similar in many ways, including their weapons systems, which include the domestic YJ-82 anti-ship cruise missile (ASCM)."

2. Towards stealth and sea denial - submarine arms race in East Asia - The Nation
"This new sail design may incorporate an additional high-frequency sonar at the base of the sail, as do some other submarines with similar designs.
...
Since 2004, China is believed to have launched 12 Type 041 Yuan-class conventional submarines, which have been progressively modified to carry more advanced high-frequency sonar, upgraded weapons systems, noise reduction and air independent propulsion (AIP) technologies."

3. China's new Yuan-class sub seen preparing for sea trials - IHS Jane's 360
"The new submarine features a new rubber anti-sonar coating which could provide outstanding reduction of acoustic signature.
...
Since 2004 12 Type 041 submarines are believed to have been launched, while the US Department of Defense estimated in its May 2013 annual report on China's military to Congress that production could reach 20 ships."

4. Yuan Type 039A Type 041 | GlobalSecurity
"Integrated with advanced noise reduction techniques including anechoic tiles, passive/active noise reduction, asymmetrical seven-blade skewed propeller, the 039A is expected to be as quiet as other modern diesel/electric powered submarines, and therefore much more difficult to be tracked. Apart from indigenously developed submarine weapon systems such as indigenous active/passive-hoyuan torpedo and the YJ-8 (C-801) submarine-launched anti-ship missile....

The electronic systems onboard the Yuan class may include CCD camera, infrared/thermal image camera, laser range-finder, surface-search radar and radar warning receiver. Various weapon systems and sensors are integrated by a digitized combat data command and control system."
 
Type 041 Yuan SSK with AIP

7veLg7o.jpg

Chinese Type 041 Yuan diesel-electric submarine with AIP (ie. air independent propulsion)


There are currently about 13 Yuan-class conventional attack submarines.[1] The Yuan SSK has many improved features.[2]

a. advanced high-frequency sonar
b. upgraded weapons systems
c. noise reduction[3][4]
d. air independent propulsion (AIP) allows a submarine to stay submerged for about three weeks
e. "This new sail design may incorporate an additional high-frequency sonar at the base of the sail, as do some other submarines with similar designs."
----------

Citations.

1. China Submarine Capabilities | NTI
"The PLAN also possesses around 13 Type 039 Song and twelve Type 041 Yuan-class submarines, which are similar in many ways, including their weapons systems, which include the domestic YJ-82 anti-ship cruise missile (ASCM)."

2. Towards stealth and sea denial - submarine arms race in East Asia - The Nation
"This new sail design may incorporate an additional high-frequency sonar at the base of the sail, as do some other submarines with similar designs.
...
Since 2004, China is believed to have launched 12 Type 041 Yuan-class conventional submarines, which have been progressively modified to carry more advanced high-frequency sonar, upgraded weapons systems, noise reduction and air independent propulsion (AIP) technologies."

3. China's new Yuan-class sub seen preparing for sea trials - IHS Jane's 360
"The new submarine features a new rubber anti-sonar coating which could provide outstanding reduction of acoustic signature.
...
Since 2004 12 Type 041 submarines are believed to have been launched, while the US Department of Defense estimated in its May 2013 annual report on China's military to Congress that production could reach 20 ships."

4. Yuan Type 039A Type 041 | GlobalSecurity
"Integrated with advanced noise reduction techniques including anechoic tiles, passive/active noise reduction, asymmetrical seven-blade skewed propeller, the 039A is expected to be as quiet as other modern diesel/electric powered submarines, and therefore much more difficult to be tracked. Apart from indigenously developed submarine weapon systems such as indigenous active/passive-hoyuan torpedo and the YJ-8 (C-801) submarine-launched anti-ship missile....

The electronic systems onboard the Yuan class may include CCD camera, infrared/thermal image camera, laser range-finder, surface-search radar and radar warning receiver. Various weapon systems and sensors are integrated by a digitized combat data command and control system."
We are also looking to buy these hope we buy 6 of these soon
 
Type 041 Yuan SSK can carry Yu-4, Yu-3, and Yu-6 torpedoes

b2StvcY.jpg

"PLA Navy crew loads a Yu-3 ASuW torpedo into the tube of a Type 039 submarine. (Source: Chinese Internet)"

The Type 041 Yuan SSK can carry the following weapons.[1]

a. YJ-2 (YJ-82) anti-ship missiles
b. Yu-4 (SAET-50) passive-homing torpedoes
c. Yu-3 (SET-65E) active/passive homing torpedoes
d. Yu-6 wake-homing torpedoes. Yu-6 can also be wire-guided.[2]
e. mines [2]

----------
Citations.

1. China's new Yuan-class sub seen preparing for sea trials - IHS Jane's 360
"Uncorroborated Chinese sources have suggested that the new variant displaces about 3,500 tons compared to about 3,000 tons for earlier Type 041s. This could indicate that the new variant has more weapons - IHS Jane's Fighting Ships states that the existing variants are armed with YJ-2 (YJ-82) anti-ship missiles and a combination of Yu-4 (SAET-50) passive homing and Yu-3 (SET-65E) active/passive homing torpedoes. Yu-6 wake-homing torpedoes may also be carried."

2. Type 041 | Deagel
"The 4,000-ton Type 041 is equipped with six 533mm torpedo tubes at the bow which can launch Yu-6 wire-guided torpedoes, YJ-82 anti-ship missiles and mines."
 
China's Yu-6 wake-homing torpedo

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China's Yu-6 heavyweight torpedo is equivalent to the US Mark 48 Mod 4 torpedo. A single Yu-6/Mark 48 can break a destroyer into two halves. The Yu-6 can be wire-guided or wake-homing.

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A naval capital ship will leave a wake as it traverses the ocean.


History of the Wake-homing Torpedo[1]

The Soviets/Russians developed the wake-homing torpedo in the 1960s.

"'The usual countermeasures are noisemakers intended to decoy an approaching homing torpedo. Unfortunately the Russians use wake-following torpedoes that do not respond to the usual countermeasures at all.'

The Russian Type-53 torpedo includes sensors that detect the churn made by ships underway. Once the torpedo senses the chopped water it will follow a ship in a S-pattern between the wakes until it finds its targets.

'Anyone who buys Russian Kilo-class submarines — almost anyone the U.S. would come into conflict with — uses torpedoes which do not respond to U.S. torpedo countermeasures,' Friedman said."

China's Yu-6 Wake-homing Torpedo

China received its first of 12 Kilo submarines from Russia in 1995.[2]

"The Chinese People’s Liberation Army Navy fields 12 Kilos with Soviet-era Type 53-65 wake homing torpedoes with a range of 11.8 miles, according to the soon to be released 16th edition of the Naval Institute Guide to Combat Fleets of the World."

This means China had 20 years to improve upon the original Russian wake-homing technology.

The United States recognizes the threat of wake-homing torpedoes like the Yu-6 and is trying to develop an anti-torpedo torpedo. However, it is experimental and no defensive weapon system is 100% effective in a real battle.

Citations.

1. Navy Develops Torpedo Killing Torpedo - USNI News
2. Kilo-class submarine - People's Liberation Army Navy
----------

Navy Develops Torpedo Killing Torpedo - USNI News

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Type 041 Yuan SSK can carry Yu-4, Yu-3, and Yu-6 torpedoes

b2StvcY.jpg

"PLA Navy crew loads a Yu-3 ASuW torpedo into the tube of a Type 039 submarine. (Source: Chinese Internet)"

The Type 041 Yuan SSK can carry the following weapons.[1]

a. YJ-2 (YJ-82) anti-ship missiles
b. Yu-4 (SAET-50) passive-homing torpedoes
c. Yu-3 (SET-65E) active/passive homing torpedoes
d. Yu-6 wake-homing torpedoes. Yu-6 can also be wire-guided.[2]
e. mines [2]

----------
Citations.

1. China's new Yuan-class sub seen preparing for sea trials - IHS Jane's 360
"Uncorroborated Chinese sources have suggested that the new variant displaces about 3,500 tons compared to about 3,000 tons for earlier Type 041s. This could indicate that the new variant has more weapons - IHS Jane's Fighting Ships states that the existing variants are armed with YJ-2 (YJ-82) anti-ship missiles and a combination of Yu-4 (SAET-50) passive homing and Yu-3 (SET-65E) active/passive homing torpedoes. Yu-6 wake-homing torpedoes may also be carried."

2. Type 041 | Deagel
"The 4,000-ton Type 041 is equipped with six 533mm torpedo tubes at the bow which can launch Yu-6 wire-guided torpedoes, YJ-82 anti-ship missiles and mines."
We need to sign contract of supply of these soon
 
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A Chinese submarine in the South China Sea in August last year. (File photo/CNS)

Beijing has revealed a version of the Type 093 midget submarine, known as the 093T, suggesting that more vessels in this class may be produced, reports news website Cankao Xiaoxi.

The 093B midget submarine reportedly has a vertical launch system that can launch 16 missiles, including the supersonic anti-ship YJ-18 and the DH-10 cruise missile.

Such a submarine can carry up to nine special ops members and is ideal for covert transportation and surprise attack. It can also launch laser-guided missiles or sneak combat divers into military ports to perform recon or destroy high-value targets such as aircraft carriers or nuclear submarines.

The United States was developing a midget version of its Ohio-class submarines but reportedly stopped development after a fire in 2008. The submarines used a dry-deck shelter system which allows the midget submarine to dock completely inside of its larger cousin. The 093T submarine adapts a wet-deck shelter system, which means only two thirds of the submarine are secured to the mother submarine and the rest is exposed to water.

PLA expands its Type 093 midget submarine line|Politics|News|WantChinaTimes.com
 
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