tim52

How Capable is the 094?

posted Tuesday July 31, 2007 under china by jeffrey

Behold, the second installment of the series on China’s SSBNs. This took a while, mainly because I wanted to reread Tom Stefanick’s Strategic Antisubmarine Warfare and Naval Strategy. It’s a classic.

Anyway, the bottom line is that I doubt China’s boomers would really be more survivable than the land-based leg of their triad. That reflects three factors: the noise level of the submarine, the range of the JL-2 and China’s geographic location.

How Quiet Is It?

The most common measure of capability is the amount of noise that the submarine makes. A noisy submarine is a dead submarine.
I see a lot of comparisons thrown around about how quiet Chin’s 093 and 094 submarines are, with comparisons to the Victor III and Los Angeles-class (USN 688) submarines.

Data for that is hard to come by, but in 1997, the Office of Naval Intelligence released a chart comparing the performance of China’s new nuclear powered attack submarine (SSN), the 093, on which the 094 is said to share a design heritage.

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Obviously, ONI didn’t release any numbers. But thanks to Tom Stefanick’s classic Strategic Antisubmarine Warfare and Naval Strategy, we can place China’s SSBN between 130-150 decibels (with a lot of specific qualifications outlined on pp272-279).

ONI’s estimate was done before we actually saw the submarine, however. An interesting comparison would be to compare the volume of the 093 to the Victor III. Modern quieting involves sound isolating mounts; Stefanick observes a relationship between quieting and larger submarines.

Sadly, I haven’t seen really convincing estimates of the surfaced displacement of the 093 or credible dimensions on the submarine to make a comparison with the Victor III. It would be nice if we had a picture of an 093 sitting at the dock.

Could China Conduct Deterrent Patrols?

The limited range of the JL-2 is a second major constraint. Various official US sources place the range as 4500 miles, 4000 nautical miles or 8000 kilometers.
NASIC is fond of saying the JL-2 will “for the first time, allow Chinese SSBNs to target portions of the United States from operating areas located near the Chinese coast.”

The operative word here is portions … as in Alaska. I may not be willing to trade Los Angeles for Taipei, as Xiong Guangkai suggested, but Anchorage is another story. Or, at least, the Chinese have to worry about that.

To target cities in CONUS – say our latte sipping friends in Seattle, for instance—Chinese boomers would have to patrol the deep waters of the North Pacific – a very long round-trip. Indeed, ONI’s suggestion that five submarines would be necessary to keep only a “near continuous” deterrent at sea suggests ONI’s analysts have reached similar conclusions about the distance of patrolling areas from China’s submarine bases.
(More on that below).

Another operational concern that points to North Pacific patrols is the need to hold at risk both Moscow and populations centers in the Continental United States. The actual operating area might be slightly larger if China’s leaders were willing to have submarines patrol out of range of some targets until receiving the order to fire.

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To reach the North Pacific, a Chinese boomer would have to transit the narrow gaps between South Korea, Japan, and Taiwan – a kind of Asian equivalent of the GIUK gap—to reach areas in the North Pacific from which the JL-2 could target significant portions of the United States.

This island chain offers a number of opportunities for fixed sensor emplacements, similar to the SOSUS system, that should provide ample opportunity for US attack submarines and other US and Japanese ASW platforms to pick up and trail the boomer on patrol. Although I wasn’t cleared the see the good stuff during my stint on the Japan desk at OSD, a review of press reporting suggests a high level of knowledge about Chinese submarine operations in and around Japanese waters.

Once out in the deep water, Chinese SSNs and SSBNs would be extremely vulnerable because deep water propagates sound very effectively. Stefanick estimates the Los Angeles-class submarine has a 25-100 nm detection advantage over the Victor III, which is probably quieter than the 093 and 094 class submarines. That reminds of a line in that silly e-mail about Chuck Norris: If you can see Chuck Norris, Chuck Norris can see you. If you can’t see Chuck Norris, you may be only seconds away from death. Replace “see” and “Chuck Norris” with “hear” and “Los Angeles-class” and now “Virginia-class” submarines.

Range is just one of the operational concerns, of course. China would also have to think about secure, survivable communications systems for patrolling boomers. This is long topic, however, and brings up much larger discussion about command and control issues.

Hainan Island?

Although the Boomer was spotted up North, near Dalian, some folks think China will eventually base the SSBN at or near the Yulin Naval Base on Hainan Island. I was skeptical that China would base the SSBN so far south. Indeed, I would have thought that basing the submarine so from from a patrolling area against North American targets would suggest a Russia-oriented role for the 094.

But ONI and others, however, seem to believe that the 094 will make the 9,000 km round-trip between Hainan Island and the patrolling area that I outlined. Assuming that the submarine travels about 10 knots (18-19 km/hour) to avoid cavitation that would compromise the location of the submarine, the round trip from Hainan to the patrolling area takes about 10 days each way (the trip is about 4300 km). Assuming the 094 has an 80 day endurance, that leaves a 60 day patrol.

All of a sudden, that ONI estimate of 5 submarines to maintain a “near continuous” presence makes sense. 5 submarines for a sixty day patrol works out to about 300 days a year. Possibly ONI estimates that the the SSBN’s have a little more endurance or that the Skippers are willing to run a few more risks to get on station. But the numbers work out about right.
Someone told Demetri Sevastopulo that basing the 094 on Hainan Island “would give its submarines easier passage and make them harder to track and target.”

Easier isn’t the same thing as easy. The submarine still has to pass through the Luzon Straitm which is relatively narrow (360 kilometers, broken into smaller passages by several islands).

Admittedly, the Luzon Strait is a complex littoral environment with lots of shipping noise in which Chinese boomers to hide and get out to sea. But the Navy can still study, model and line with the Strait with sensors. This fact is not lost on the Office of Naval Research, which seems to be very interested in the “unique oceanography observed in the South China Sea” and seems to have funded a fair amount of research including the Asian Seas International Acoustics Experiment (ASIAEX), Windy Islands Soliton Experiment (WISE) and god knows what else.

And, of course, once through the Luzon Strait, a skipper still has the problem that deep water propagates sound.

We might need a few more boats to get this done (I haven’t done an estimate), but I find it difficult to imagine problems that could not be solved by giving Representative Courtney his extra attack submarine for his district.
On the other hand, if China envisioned the 094 as solely a deterrent against Russia, the operational challenges for the 094 are less daunting. Moscow is in range of shallow offshore areas that are near China’s naval bases and far away from Russia’s submarine and other ASW forces.

The fact that China is building an SSBN with substantial Russian assistance that seems far more better suited to striking Moscow … well that strikes me as a pretty decent indicator of the degree to which technological imperatives – rather than operational requirements – continue to drive the SSBN program.

A Surge Strategy?

Were China to keep a deterrent on patrol in the Northern Pacific, I would expect that the United States Navy would be quite capable of detecting the submarine coming out of port and trailing it on patrol—absent criminal negligence on their part or, more likely, those who fund and equip them.

Last week, I suggested that the jury was still out on whether China will send its deterrent to sea. Although countries have done crazier things, the technological limits of the missile and submarine interact with the unfavorable geography for China’s boomer fleet in such a way to undermine the case in favor of putting the deterrent out to sea.

Of course – as I said last week—bureaucratic imperatives might outweigh solid policy analysis. But I don’t judge the 094 to be very survivable platform, given US intelligence estimates, for deterrent patrols against the United States.

Other strategies are, of course, possible. I am kind of playing around with the idea that China might build a small number of SSBNs that remain in port, but that could be “surge” out to sea during the early phases of a conflict. A lucky Captain might slip through if US and Japanese ASW assets are busy with China’s diesel submarines.

That, of course, raises the prospect of a serious miscalculation during a deep crisis, which just happens to be the subject of my next post.

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