Chinese submarines thread

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crobato

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Re: Chinese sub thread

If your assumptions about 091 mod types and three 093/093A types actually existing would prove correct dear Crobato and Roger; I would be left wondering:
Were the recent editions of the DoD report about China's military intended as an exercise in disseminating disinformation, just crappy bullshit produced by a hapless DoD intern or are there indeed some ´knowledge gaps´ better kept under wraps and shielded from potential criticism from Congress?

What do you think Crobato, Roger ...?

The projected numbers are not bullshit but are based on very logical assumptions even if they still need to be proven with hard evidence. The latter is not easy due to the lack of transparency and public admission.

For example, in order to have a true 24 hour around the clock deterrance you would need at least 3 to 4 boomer subs, with at least one ship in constant patrol. Regardless of whatever "Chinese indigenous characteristic" you may apply to what the PLAN may be "planning", we know well enough that the PLA does follow or even go out of its way to mimic Western or US characteristics.

Some of these assumptions you cannot avoid. Note that the Russians are building a total of 3 Borei class subs. That's the minimum you need for deterrance.

If they never build a second Xia class, and PLAN wants a minimum deterrance force, they have to make the Xia 406 operational, and bring two of the enhanced Xia class online. If 406 is not operational, then three of the enhanced subs.

Another is that you have to assume that the attack subs themselves are going to be built in a flotilla basis. Especially since we are now seeing that the PLAN adopting group or flotilla tactics in their subs rather than lone wolf tactics. In fact, it was the PLA's own articles and news releases that say so. A flotilla is at least four ships.

Note how ship groupings in the PLAN revolves around a unit of four.

The Han subs --- 402, 403, 404 and 405

The Kilos are a total of 12 --- 3 groups of four. That means a flotilla for every fleet --- North, East, and South.

I am expecting that the Songs should be around 12 for the same reason. 3 flotillas, with one for each fleet. If they built more than that, expect in increments of four, 16 being the next number, followed by 20.

The Houbei probably around a minimum of 12, to 24, or 2 flotillas per fleet for the last.

At least 24 engines are ordered, and with two each for every 054A class, that means a total of 12 ships, nicely separated into 3 flotillas each.

I don't know if they are willing to build at least four modified 091 class, if their purpose extends to tactical and training development. I am thinking the 091 modified is for technological purposes only, and I speculate, if Han 402 has been retired, then the modified Han takes it place.

They should probably at least build a flotilla of 093s, combined both version with the sail on tower and without. Probably two of the ones with the sail, and two without.

It isn't just technological development the PLAN is interested in, but in the training and tactical. Obsolescence does not affect your training and tactical development roles. The 093s along with the Hans, can be used for that to help usher a new generation of crews that can handle 095s.

Note the need for training and tactical development will also apply to the enhanced 092s and 094s.

I would expect no less than four Yuans also in the near term.
 

szbd

Junior Member
Re: Chinese sub thread

To build them is one thing. To operate them is another. When the PLAN is able to put to sea it's sub force in numbers with highly trained crews that are professional, proficent and "salty". Then and only then will they be a viable sub force.

Salty= A sailor who has years of experience of actual at sea time.

Chinese also use the word salty (the actual english word) as an internet slang, means one has too much spare time...
 

Roger604

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Re: Chinese sub thread

we will know whether pump jet is on 093/094 when we see the next conventional sub coming out. If that one has pump jet, then we can venture to guess that the more important nuclear subs will get the latest technology.

I read that pump jets are not suitable for SSK because they are less energy efficient and SSK cannot provide enough energy without unacceptably sacrificing endurance. That's why the most advanced SSK's don't have pump jets.

As for Kilo, it's no where near the pinnacle of SSK technology, it's still probably an order or more noisier than Amur, which is still noisier than leading conventional subs like Oyashio and Collins.

If the Yuan submarine has AIP (as speculated on the Sinodefence page) would you say it's in the same acoustic class as the Lada/Amur or still significantly behind?
 

tphuang

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Re: Chinese sub thread

I read that pump jets are not suitable for SSK because they are less energy efficient and SSK cannot provide enough energy without unacceptably sacrificing endurance. That's why the most advanced SSK's don't have pump jets.



If the Yuan submarine has AIP (as speculated on the Sinodefence page) would you say it's in the same acoustic class as the Lada/Amur or still significantly behind?

hmm, they have a kilo sub fitted with pump jet. Although that could be just experiment. French are using pump jet for barracuda, but not scorpene. That's about the only nation that has pump jet technology but do not use it for diesel subs. Anyway, I thought about it a little more and it seems that there is probably good reason that they are not showing the propeller (or come close to showing it).

As for Yuan, I've always looked at it as a modified Song. In fact, that's why it's referred to as 039A by PLAN. If you looked at it, it seems to be a testbed in many ways. After Song sub used the U-214 battery (I think recent version of kanwa probably said 12 or 15 sets were imported), Yuan moved to a domestic AIP engine. And it seemed to also took some ideas from Kilo. Either way, I don't have any figures, but my belief is that Yuan is probably just slightly better than Kilo. And we will have to wait until the next class of conventional subs before matching the performance of say Scorpene/U-214/Amur.
 

yehe

Junior Member
Re: Chinese sub thread

One has to take into account that larger diameter subs usually mean quieter subs, for the same tech level. Thing is, all the quieting of US subs in the past few decades hasn't come by by some wizard like super high tech solutions - most of if came by very, very delicated thought out conventional engineering. Key is to detach anything that produces sound from the submarine itself - and put it on harnesses, various shock absorbers, etc. To minimize vibrations as much as possible. And all that insulation requires primarely space. That is not to say that design principle of coolant pumps or design of the propeller itself doesn't influence the overall noise levels a lot - of course it does. But every little piece of the puzzle must work perfectly in order to get the desired result. Sturgeon class, US first quiet sub, was to be very quiet on paper, only to be discovered that first one produced was rather noisy. Why? Cause the builders didn't pay enough attention to precision of their work. An extra decibel of sound got added here, extra two there, and in the end it was rather different than the design called for. Subsequent subs got much quieter after additional, very strict quality control was integrated into the building process.

Agree to that, noice level of subs are not exactly based on any new high tech invention, at least not mainly, its based on solution knowhow and pricision, it doesnt take generations after generations to get improvement, I remember the Soviet greatly improved their Sub's noise level in a relatively very short period of time, Seawolf/Verginia is no great leap from previous USN SSN class in terms of noise level, its more of a internal digitalization, fire control and sensor improvement imo.
093 however I think is still too small, maybe the PLAN intend to use it in seas more close to the coastal area.
 

szbd

Junior Member
Re: Chinese sub thread

I read that pump jets are not suitable for SSK because they are less energy efficient and SSK cannot provide enough energy without unacceptably sacrificing endurance. That's why the most advanced SSK's don't have pump jets.

The whole thing about bump jet is to control the water current field. There are a lot of issues to concern and many many research and experiments need to be done. For example, the greater the number of stators and rotors, the lower the noise but also the lower the power efficiency. Also there are quite some different designs of bump jet, each has advantage and short commings. For example Triomphant use stators in front of rotors design, which produce relatively more noise but easier to control plus the system is ligher and smaller, while sea wolf uses the reverse design. We can't say bump jet as a whole is good or bad, the key is your actual technology.
 

Roger604

Senior Member
Re: Chinese sub thread

It's just a mistaken perception caused by the thinness of the sail. Here is a photograph showing people on the Type 093 sail. Compare with this photograph of people on the Seawolf sail.

The Type 093 sail appears to be about 1/6.5 the length of the hull. The sail of the Seawolf is about 40 feet (not counting the curvy part on the bottom). The body is about 350 feet. So the ratio is 1 to 8.75.

The Type 093 sail appears to be 1.5x the length of the Seawolf, so about 60 feet. That means the length of Type 093 is about 390 feet.

The Seawolf displacement is 9137 tons, so multiplying by the ratio of the length, Type 093 is about 10,180 tons dived. But looking at the photographs, Type 093 is a lot thinner than the Seawolf, so Type 093 is probably about 7,000-9,000 tons dived.

118464626112382nf0.jpg


seawolf5.jpg



REVISED:

With new pictures, it looks Type 093's hull is 7x the length of its sail. So it's actually about 420 feet long. So if it was as fat as Seawolf, it's displacement would be 10,964 tons. But looks thinner, so 8,000-9,000 tons is closer.
 
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szbd

Junior Member
Re: Chinese sub thread

How did you get "The Type 093 sail appears to be 1.5x the length of the Seawolf"
 
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