PLAN submarines Thread II

[crobato]

The Han actually has a good hydrodynamic design with a rounded Albacore-teardrop shape and body of revolution, so the starting point is quite good. The improvements for the 091G appear at least a quiet slow turning propeller and flank sonars. The reactor should have been upgraded too. By all means it may be an old sub, but seriously updated. On the hull design, the world hasn't moved much beyond the Albacore hull "body of revolution" design first developed in the fifties.

The Mings on the other hand, has a hull design that goes back to WWII, so the hydrodynamic design is generations obsolete. The Ming is derived from the Romeo which in turn was derived from the German Type XXI Uboat that was ready to be deployed at the end of WWII. So it has the traditional long and thin hull. China got its first hand in building submarines by assembling Romeos from kits supplied by the USSR, and later learned to build the Romeo entirely by itself. For all its worth, there was nothing there that would have thought Chinese designers to make a leap and design a body of revolution Albacore type hull. The Xia is basically an extended Han with a missile compartment in the middle.

So in terms of structural design and hydrodynamics, the Han is a major leap over the Romeo and Ming, just as the Albacore was over the Gato class. The Song is the first Chinese SSK to incorporate a body of revolution design although its not the first Chinese sub per se with this design, the Han was. What surprises me about the Song is the rounded knife bow, which is kind of like the Agosta 90s, compared to the Han class which has a rounded spherical bow. Then the Kilo came to China and the Yuan goes back to the rounded bow, going back full circle what the Han had originally.

FYI, the first generation of nuclear subs the US and USSR had were the long and thin ones, like the Skate, Nautilus and November classes. Body of revolution designs began with the USA with the Skipjack class for the SSN, Barbel class for the SSK, and for the USSR, with the Victor class for the SSNs. Traditionally Soviet SSKs were also long and thin, like the Foxtrot and Tangos, it was the Kilo that first had the body of revolution design.

In the design sense, here, we like to call the "old" subs the ones that had the long thin design (e.g. Romeos, Mings, Golf), vs. the "modern" subs that have the teardrop body of revolution design (Han, Xia, Song, Kilo, Yuan, Shang, and Jin). All of the Han's problems have been internal---reactor reliability and noise, etc,. But if the internal problems are addressed, this sub can slice cleanly through the water. The Ming on the other hand is fugly to the water as it is to the eye, and no matter how you fix the internals, you can't fix the outside.

[dlhh]

The Han actually has a good hydrodynamic design with a rounded Albacore-teardrop shape and body of revolution, so the starting point is quite good. The improvements for the 091G appear at least a quiet slow turning propeller and flank sonars. The reactor should have been upgraded too. By all means it may be an old sub, but seriously updated. On the hull design, the world hasn't moved much beyond the Albacore hull "body of revolution" design first developed in the fifties.

I noticed with some of the utube videos of the Song that they have 2 periscopes with 2 people looking through it at the same time. Subs advantages is its stealth and subs are suppose to identify the enemy through passive sonar. With the latest airborne radar able to spot and track sub periscopes at long distances, its a very risky way to identify ships.

One problem is the PLA Navy does not patrol outside its littoral waters so its subs does not have sound tracks of potential enemys propellers sounds.

[Pointblank]

I noticed with some of the utube videos of the Song that they have 2 periscopes with 2 people looking through it at the same time. Subs advantages is its stealth and subs are suppose to identify the enemy through passive sonar. With the latest airborne radar able to spot and track sub periscopes at long distances, its a very risky way to identify ships.

One problem is the PLA Navy does not patrol outside its littoral waters so its subs does not have sound tracks of potential enemys propellers sounds.

You still need visual confirmation to shoot at targets at times. Sometimes, you cannot tell if a ship is friendly or enemy and must observe visually to ascertain intentions and type. Furthermore, most submarines use two periscopes; one attack periscope, and a observation periscope.

[man overbored]

You still need visual confirmation to shoot at targets at times. Sometimes, you cannot tell if a ship is friendly or enemy and must observe visually to ascertain intentions and type. Furthermore, most submarines use two periscopes; one attack periscope, and a observation periscope.

Not true. You can id a threat ship or sub by purely acoustic means. The US and Nato allies were able to identify not only the class of Soviet sub through acoustic means, but to identify individual units within a class, as each ship and sub has some unique acoustic quirk, such as a noisy pump, a rough shaft bearing or a nick in a propeller whose acoustics will show up distinctly on your waterfall display. A threat library will automatically identify the class and unit. Generating the threat library required allied subs and ASW airplanes to trail every threat unit as it left each overhaul to record it's individual acoustic signature. This was standard practice during the cold war when I served and was done with great care as our lives depended on this information.
Merchant ship id required poking a periscope up of course. This is hazardous to do, as the P-3, Nimrod or SH-2F and SH-60B had a radar designed specifically for finding periscopes and snorkels on the surface.
A diesel boat dieseling to it's patrol area is noisy as all heck. It is no trouble to track. Once it reaches it's patrol area it can go pretty silent, but you will know it's location when it begins it's patrol. You mark this position, draw the correct sized circle around it and avoid the area. Diesel subs on their diesels are about the noisiest things imaginable, plus they have a nice IR signature even some satellites can track. Diesel boats are far too slow to operate offensively against a carrier strike group, the carrier and her escorts could simply outrun any DE boat ever built, and even a few torpedos ( yes, some French torps are that slow ) and doing so they would make an awful racket. Only a good quiet SSN like Russia's Akula's or Sierra class are a real threat to our carriers. They can spend the hours necessary to stalk the carrier and set up their shot and not make too much noise doing so. The reality is both sides use considerably less than maximum speed to maintain silent running. Escorts will use "sprint and drift" techniques. The problem is that a modern surface combatant with skewed props and a bubbler system to attenuate internal noise ( something like Prairie Masker which coats the surface of the hull and props with a thing layer of air bubbles ) are very darn quiet, and for a diesel sub to keep up for any amount of time will necessitate using it's diesels. At that point the game is very much over for that sub. It will be pinned down while the carrier leaves the area. During the cold war we would park a frigate on top of Soviet subs and ping the living crap out of the crew with our sonar. Most humilating. In an actual war we would have torpedoed this sub.

[crobato]

None of this eliminates the need for a periscope, like in times you want to surface but you don't want to do it from the bottom of a fishing boat, which already did happen to one sub. Periscopes themselves have undergone their own revolution, going away from traditional designs, to "photonic" ones, which are basically electronic with digital video cameras.

[PrOeLiTeZ]

id targets can be done by accoustic signature why else do you think the make so much noise when towing the 093/094. Dunno maybe to hide the 093/094 signature from Western forces knowing the accoustic signature maybe.

[dlhh]

None of this eliminates the need for a periscope, like in times you want to surface but you don't want to do it from the bottom of a fishing boat, which already did happen to one sub. Periscopes themselves have undergone their own revolution, going away from traditional designs, to "photonic" ones, which are basically electronic with digital video cameras.

Crobato & Man Overboard

PLA Navy subs at present only operate in littoral waters as a defensive shield. Its doubtful that they will survive out of their territorial waters due to their lack of experience especially in identifying their potential enemy's acoustic signatures.

It different in their own territory as thay have the air force plus their own coastal passive sonars to help identify potentail threats esp from enemy subs.

The question in the future is how the SSBN & SSN is suppose to patrol outside their own waters to be effective deterrents? Without any experience plus lack of data library in acoustic signatures, its a tall order indeed!

What are your thoughts on this?

[crobato]

Define littoral waters. The PLAN sees its scope not just the 12 mile territorial sea zone but also sees the need to exert itself throughout the claimed EEZ. That's like 200 nautical miles off the coast and includes the continental shelf. Remember the 2003 incident when a Ming suddenly surfaced near JSMDF exercises. Its been sitting there for a while and presumably that's toward the east side of the East China sea. And again the Song incident with the Kitty Hawk. Though the exact location is not disclosed, one can presume these exercises are taking place towards the eastern side of the Ryukus. I have a theory that both subs were gathering signatures and taking sampling data of the water densities and temperatures.

You don't really need subs to gather oceanic water data and acoustic signatures. You can do it covertly with disguised ships, like fishing boats or 'oceanographic research" vessels.. There are also special vessels for that task. Lately there are pictures of a ship that is built like a Swath and is intended to function as a SURTASS. Also, there is a report that the PRC is putting a network of SOSUS on its own.

One thing of note. Working with sonar signatures is a lot easier in open water than in littoral. Why? Take this analogy. You get a car. You take the car roaring in an open country road without cars. The car will be the only noise around for miles. That's your open ocean. Take the same car. Put it in the middle of the busiest intersection of New York or Hong Kong or Bangkok. Rush hour. Now try to hear and isolate the sound of your car's engine in that traffic. That's littoral environment for you.

Now if you're dealing with hundreds, if not thousands of acoustic signatures at the same time, then ask to identify the correct one within 30 seconds, that will of course be difficult. That's where computers come in with acoustic sound databases to make all these comparisons. It gets worst the more the sonar is sensitive because the more sensitive it is, the more sound sources it picks up. These computers would also factor the water conditions (temperature, density, etc,.) in analyzing the signatures, since sound signatures can be altered with water conditions.

One thing I must note that in one of the videos where CCTV showed the insides of the Song, there are crewman sitting in workstations and in the background there appears to be rack style server cabinets. So whatever they are using, it has removable and upgradable server racks, similar to commercial PC servers, and no doubt uses COTS computing technologies (e.g. commercial processor chips).

For open water, what is important is acoustic or sound management. Compared to littoral waters, cold open water not only has less extraneous sound sources (e.g. biologics, ship traffic, etc,.) but the coldness means higher water densities and more sensitivity to sound. Open water is a lot less forgiving for noisy subs than littoral waters. If the 093/094 goes to the open water, acoustic management is what they should practice.

[man overbored]

Subs are essential for recording the acoustic signatures of other subs. Surface sensors cannot tail a sub closely the way one of your own subs can. Air and surface assets certainly play a part, but without subs tailing other subs the threat library will never be complete.
You are correct that the acoustic problem in shallow water is difficult. There will be lots of noise from coastal traffic and the bottom conditions and warmth of the water muddies the acoustics. The Persian Gulf is horrible acoustically! Of course this cuts both ways. The sub sitting still waiting for it's prey is equally deaf. Go ahead, poke your periscope up. SURTASS and SOSUS already followed the boat to it's patrol area, so this is well known. A P-3 is now hanging out waiting for this boat to snorkel or poke a periscope up. This is how the game would be played.
One thing most enthusiasts miss regarding DE boats is that they simply do not have the electrical power for the sorts of sensors found on the best nuclear subs. Batteries not only limit top speed ( even when the diesel is running, a bank of batteries cannot generate the current necessary to turn that electric motor with the sort of power found on a nuke so DE boats are just plain slow, but the nuke also has a huge advantage in the power of it's sensors due to all the electrical current they make ) but limit the DE sub's sensors. Given equal acoustics, the nuclear sub will detect the DE boat earlier simply by virtue of the nuke's superior sensors.

[crobato]

That's true. However you didn't seem to account that there has been a revolution in battery technology. No longer just lead acid by nickel-cadmium, then nickel-hydride, then silver, then aluminum and lithium batteries. For the size and weight they are a lot more powerful. Still another development is that today's computers have all sorts of power saving measures in them, and they offer vastly more computing power exponentially for the wattage they consume. Combine the low power computing revolution and the battery revolution and you have a whole new ball game in your hands.

The third is the development of AIP. This means the sub can now recharge underwater.

[dlhh]

That's true. However you didn't seem to account that there has been a revolution in battery technology. No longer just lead acid by nickel-cadmium, then nickel-hydride, then silver, then aluminum and lithium batteries. For the size and weight they are a lot more powerful. Still another development is that today's computers have all sorts of power saving measures in them, and they offer vastly more computing power exponentially for the wattage they consume. Combine the low power computing revolution and the battery revolution and you have a whole new ball game in your hands.

The third is the development of AIP. This means the sub can now recharge underwater.

Thanks Crobato & Man Overbored.

PLA should also be brave to exercise with other navies to get more experience. You cannot improve by just exercising with yourself.

Pakistan & Russain will come to mind plus the navies of Asean.

Pakistan has ordered the German U-212 boats, one of the quietest plus thay are going to upgrade their Agosta's to AIP. Russia navies are good too.

PLA should just use their upgraded Songs and Yuans to exercise if they do not want to give too much away of their SSN. Whatever deficiences can then be rectified.

The US Navy have also said they see no problem with PLA exercising with Asean. Of course, withn their influence, they will know the weakness of PLA in these exercises, but its better to improve in peace rather than in conflict.

[crobato]

Sooner or later PLAN cannot act timid or xenophobic. They have to run the risk of 093s and 094s getting their signatures caught, but in return, and I think the penalty is acceptable, they get to train their crews in open waters and get valuable experience. Letting the Songs and Yuans do all the work isn't going to solve anything. They have to come out of the woodwork sooner or later on the nukes.

In a way, its sort of happening. Last year, Taiwan defense minister complained about Chinese subs at the eastern seaboard of Taiwan.

I think exercising with the Russian Pacific fleet would be the better idea.

[man overbored]

Last year the PLAN made a grand total of six submarine deployments according to US Navy records as presented in testimony to Congress on the Chinese Navy. In 2006 the PLAN had exactly one submaring deployment, and in 2005 there were none at all. This is public knowledge. Whether or not the USN has good sound signatures is of course not open knowledge, but if we had boats there to record their deployments............
Training is definitely in short supply for the PLAN sub force. The only way to know what wears out over a long deployment in wartime is to make long deployments during peace time and wear stuff out. The PLAN cannot begin to know their spares useage, mean time between failure of a multitude of components, or have even a rough idea of how busy their overhaul shops will be and what staffing will be required in a war because they do not operate their boats hard in peacetime. They will come up short on trained techs and parts, and boats will sit at the pier. Not to mention the crews will have no experience with long deployments and the psychological affects these have. They won't have experienced that mid deployment funk when everyone is on everyone elses nerves and tempers start to flair 'cause it's been so friggen long since that last cold beer. That's when a good skipper has a steel beach picnic or the submarine equivalent ( a "Hollywood shower" with lots of hot water ), or maybe pulls out a great movie he had stashed unknown to the crew. You have to long cruise to know how to lead a crew when the going gets tough.

[crobato]

Since this thread is headed into general submarine issue discussion, I'm going to merge the thread with the main one to keep things neat and organized.

[dlhh]

There no doubt that the US Navy have passive sonar arrays laid across the ocean from okinawa to taiwan. Thats why they know how many deep ocean sorties the PLAN subs makes. Remember the incident when they tracked a Han sub all the way to Guam and back via Japan territorial waters.

Lets see what happens in future, whether the PLAN wants to be a respected force or they still want to be minor player, playing only among themselves.