The sequel.
Anyway to start with, I have some thoughts.
1. Some thought about the stationing of subs in Sanya, Hainan. Subs tend to be designed by countries that are in colder climates, hence colder waters. Thus how they deal with cooling, to their sonar issues, have a tendency to be biased towards cold waters. When it comes to warm waters, or tropical conditions, warm waters can expose a new bag of issues to submarines whose design did not foresee warm water effects.
In China's case, their SSKs, the Song and the Yuan, appeared designed and built by shipyards that are more to the south or middle of China, and therefore faces a more moderate to semi-tropical environment. These subs probably have greater consideration to tropical climates, hence they were the first to be stationed to the south.
But Huludao is a different case being far up north. This is a place that is cold enough to have snowstorms and ice forming in the water. As China's nuclear subs are born there, their cooling requirements among other things may have been oriented at first to that region. Hence the stationing of the Hans and Xia to the North Sea Fleet, and so was the early 093 and 094.
But the appearance of the improved Han (091G), the 093 and 094 as far south as Sanya, Hainan indicates tropicalization measures and testing are being imposed on the subs, to turn them from "cold water" to "all water" subs.
2. The second issue that I like to raise, and its been in my mind for some time now, is the so called "smooth look" that has been with some European subs, particularly German and Swedish. This look is one with straight upper deck and angled upper sides of the body. The British have also decided to run this look too, and lately the Japanese are converts to this approach, based on the look of the Soryu class sub.
Is this design really better? Some of the most quietest subs in the world actually never chose to have this approach, and they include the Seawolf, Virginia and the French Scorpene class. These last three subs still favor the rounded body look that was pioneered long ago by the Albacore.
So what is the theory behind this angled smooth look that the Germans and Swedish came up with? If I think about it, its not really hydrodynamics. Submarine hydrodynamic design reached a perfect stage when the Albacore came out back in the fifties, and that sub actually has a speed record faster than nuclear subs even though it only had diesels. The optimal design for speed, as that sub showed, is one based on the fish it was named for.
The straight upper deck and angled sides of the German and Swedish subs in a sense is not actually hydrodynamic but contrary to it, its not really streamlined. So I have another theory as the angled sides and straight look reminded me of something else, something you see in the latest fighters and surface ships---stealth.
Having straight lines and angled sides are meant to minimize reflection from going into different directions. Instead, these reflections are aimed into as few directions as possible. The less directions the reflections are scattered, the better.
If this principle can work with radar, it can work on sonar.
This does not mean the sub is going to be quiet. This design has nothing to do with quietness or passive stealth. Rather, it is meant to counter active sonar, reducing the range of detection and echoes from a hunting ping. Active sonar is actually the last and best resort to defeat a quiet SSK, because no matter how quiet you are, you won't escape your own reflections. Usually, subs have adopted using all sorts of coatings and tiles to help counter active sonar. However, we all know even from aircraft to ships, that designing to counter reflections from the start, is a superior method over applied methods such as coatings like RAM and so on.
The con to this is that the sub may not be as hydrodynamically efficient or even as quiet once the speed picks up. This however can be empirically adjusted and fine tuned through wind tunnel and water tank testing. For SSKs running at slow speeds it probably is a better judgement call, to have more active sonar stealth over hydrodynamic efficiency at higher speeds.
The US, Russian, French and it seems even to the Chinese, that their emphasis is speed and to reduce flow noise for burst, cruise or transit speeds, and for tactical speeds. It may seem counter intuitive to some, but you can actually reduce drag and noise through a more "disturbed" rather than a clean look towards the middle to end of the body. This is similar to the nipples in a golf ball. One way to achieve this is to strategically design and position your limber holes and other small protrusions, and you can empirically determine this by wind tunnel and water tank testing. This can explain the look and adjustments I've seen with many subs on their limber hole patterns.
My theory goes, that the "rounded" subs are probably hydrodynamically quieter than the "angled" subs at speed, not counting other noise producing factors like powerplant, but once the subs go actively pinging, the rounded subs would be in a disadvantage over the angled subs.
The question now remains what is the trend for future PLAN submarines? Will they still go after hydrodynamic efficiency as the Yuan and Shangs still do? Or like those certain models show, a shift towards being able to counter active sonar as well?
3. The third thing I like to bring out are the Red and Blue Flag exercises. Certainly the J-10 vs. J-11 encounters are probably well known among the Chinese watchers now. Through these exercises, you can actually shape policy.
But does the PLAN's ship and sub policy changed by similar exercises? Of course we will never know the results of sub vs. sub encounters within the PLAN, e.g. Yuan vs. Shang, Song vs. Kilo, PLAN SSKs vs. PLAN SSNs, etc,. Hypothetically, if you are in the PLAN's place, and you conduct such exercises, will the results of these exercises help shape future policy and purchasing plans? One thing I noticed that in China, you don't stick completely to the long term plans but make adjustments along the way, and must be flexible even to change the long term plans if they were shown to be wrong or obsolete. Its not hard to imagine that Shangs and Improved Hans working as Blue forces, with Jins or the improved Xia thrown in as targets or hunters, against Songs, Yuans, Kilos and Mings acting as Red forces.
Anyway to start with, I have some thoughts.
1. Some thought about the stationing of subs in Sanya, Hainan. Subs tend to be designed by countries that are in colder climates, hence colder waters. Thus how they deal with cooling, to their sonar issues, have a tendency to be biased towards cold waters. When it comes to warm waters, or tropical conditions, warm waters can expose a new bag of issues to submarines whose design did not foresee warm water effects.
In China's case, their SSKs, the Song and the Yuan, appeared designed and built by shipyards that are more to the south or middle of China, and therefore faces a more moderate to semi-tropical environment. These subs probably have greater consideration to tropical climates, hence they were the first to be stationed to the south.
But Huludao is a different case being far up north. This is a place that is cold enough to have snowstorms and ice forming in the water. As China's nuclear subs are born there, their cooling requirements among other things may have been oriented at first to that region. Hence the stationing of the Hans and Xia to the North Sea Fleet, and so was the early 093 and 094.
But the appearance of the improved Han (091G), the 093 and 094 as far south as Sanya, Hainan indicates tropicalization measures and testing are being imposed on the subs, to turn them from "cold water" to "all water" subs.
2. The second issue that I like to raise, and its been in my mind for some time now, is the so called "smooth look" that has been with some European subs, particularly German and Swedish. This look is one with straight upper deck and angled upper sides of the body. The British have also decided to run this look too, and lately the Japanese are converts to this approach, based on the look of the Soryu class sub.
Is this design really better? Some of the most quietest subs in the world actually never chose to have this approach, and they include the Seawolf, Virginia and the French Scorpene class. These last three subs still favor the rounded body look that was pioneered long ago by the Albacore.
So what is the theory behind this angled smooth look that the Germans and Swedish came up with? If I think about it, its not really hydrodynamics. Submarine hydrodynamic design reached a perfect stage when the Albacore came out back in the fifties, and that sub actually has a speed record faster than nuclear subs even though it only had diesels. The optimal design for speed, as that sub showed, is one based on the fish it was named for.
The straight upper deck and angled sides of the German and Swedish subs in a sense is not actually hydrodynamic but contrary to it, its not really streamlined. So I have another theory as the angled sides and straight look reminded me of something else, something you see in the latest fighters and surface ships---stealth.
Having straight lines and angled sides are meant to minimize reflection from going into different directions. Instead, these reflections are aimed into as few directions as possible. The less directions the reflections are scattered, the better.
If this principle can work with radar, it can work on sonar.
This does not mean the sub is going to be quiet. This design has nothing to do with quietness or passive stealth. Rather, it is meant to counter active sonar, reducing the range of detection and echoes from a hunting ping. Active sonar is actually the last and best resort to defeat a quiet SSK, because no matter how quiet you are, you won't escape your own reflections. Usually, subs have adopted using all sorts of coatings and tiles to help counter active sonar. However, we all know even from aircraft to ships, that designing to counter reflections from the start, is a superior method over applied methods such as coatings like RAM and so on.
The con to this is that the sub may not be as hydrodynamically efficient or even as quiet once the speed picks up. This however can be empirically adjusted and fine tuned through wind tunnel and water tank testing. For SSKs running at slow speeds it probably is a better judgement call, to have more active sonar stealth over hydrodynamic efficiency at higher speeds.
The US, Russian, French and it seems even to the Chinese, that their emphasis is speed and to reduce flow noise for burst, cruise or transit speeds, and for tactical speeds. It may seem counter intuitive to some, but you can actually reduce drag and noise through a more "disturbed" rather than a clean look towards the middle to end of the body. This is similar to the nipples in a golf ball. One way to achieve this is to strategically design and position your limber holes and other small protrusions, and you can empirically determine this by wind tunnel and water tank testing. This can explain the look and adjustments I've seen with many subs on their limber hole patterns.
My theory goes, that the "rounded" subs are probably hydrodynamically quieter than the "angled" subs at speed, not counting other noise producing factors like powerplant, but once the subs go actively pinging, the rounded subs would be in a disadvantage over the angled subs.
The question now remains what is the trend for future PLAN submarines? Will they still go after hydrodynamic efficiency as the Yuan and Shangs still do? Or like those certain models show, a shift towards being able to counter active sonar as well?
3. The third thing I like to bring out are the Red and Blue Flag exercises. Certainly the J-10 vs. J-11 encounters are probably well known among the Chinese watchers now. Through these exercises, you can actually shape policy.
But does the PLAN's ship and sub policy changed by similar exercises? Of course we will never know the results of sub vs. sub encounters within the PLAN, e.g. Yuan vs. Shang, Song vs. Kilo, PLAN SSKs vs. PLAN SSNs, etc,. Hypothetically, if you are in the PLAN's place, and you conduct such exercises, will the results of these exercises help shape future policy and purchasing plans? One thing I noticed that in China, you don't stick completely to the long term plans but make adjustments along the way, and must be flexible even to change the long term plans if they were shown to be wrong or obsolete. Its not hard to imagine that Shangs and Improved Hans working as Blue forces, with Jins or the improved Xia thrown in as targets or hunters, against Songs, Yuans, Kilos and Mings acting as Red forces.
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