China’s Submarine Fleet Continues Low Patrol Rate

China’s entire submarine fleet conducted only two patrols in 2006, according to information declassified by the U.S. Navy and obtained by the Federation of American Scientists under the Freedom of Information Act. The low patrol rate follows a drop from an all-time high of only six patrols in 2000 to none in 2005. China’s single sea-launched ballistic missile submarine Xia, the data shows, has never conducted a deterrent patrol.

The low level of Chinese submarine patrols is a curious contrast to warnings by the Pentagon, some private institutes and news media that China is expanding its submarine operations deeper into the Pacific. Although Chinese submarines occasionally venture into the waters around Japan and Taiwan, the fleet is surprisingly inactive.

Since 1981, the first year for which patrol data is available, the Chinese submarine force has conducted an average of less than two patrols per year. The highest number of annual patrols conducted since 1981 was six patrols in 2000. In four years (1982, 1990, 1993 and 2005), no patrols were conducted at all. Over the 25-year period, the trend is that patrols have only increased from one per year to approximately 2.8 patrols per year.

Chinese Submarine Patrols

The entire Chinese submarine fleet conducts less than three patrols per year on average. The ballistic missile submarine Xia has never conducted a deterrent patrol.

So What is a Patrol?

The Navy has refused to tell FAS what a “patrol” is, saying doing so “would divulge methods and sources.” So interpretation of the data comes with a great deal of uncertainty. But the Defense Department’s unclassified Dictionary of Military Terms (JP 1-02) and earlier versions provide some hints by listing the following five definitions:

* Antisubmarine patrol: The systematic and continuing investigation of an
area or along a line to detect or hamper submarines, used when the direction
of submarine movement can be established.

* Inshore patrol: A naval defense patrol operating generally within a naval
defense coastal area and comprising all elements of harbor defenses, the
coastal lookout system, patrol craft supporting bases, aircraft, and Coast
Guard stations.

* Offshore patrol: A naval defense patrol operating in the outer areas of
navigable coastal waters. It is a part of the naval local defense forces
consisting of naval ships and aircraft and operates outside those areas
assigned to the inshore patrol.

* Patrol: A detachment of ground, sea, or air forces sent out for the purpose
of gathering information or carrying out a destructive, harassing, mopping up,
or security mission.

* Submarine patrol area: A restricted area established to allow submarine
operations: a. unimpeded by the operation of, or possible attack from, friendly
forces in wartime; b. without submerged mutual interference in peacetime.

If one assumes that U.S. Naval Intelligence’s use of the term “patrol” follows the DOD’s definitions, then the declassified patrol data suggests that Chinese general purpose submarines in 2006 twice conducted investigations to detect other submarines, participated in naval defense operations in coastal or outside coastal areas, or deployed for the purpose of gathering information or harassing. That implies an almost dormant submarine fleet.

The Song Incident

One of the two patrols conducted in 2006 appears to have been the widely reported surfacing of a Song-class diesel-electric submarine near the U.S. aircraft carrier USS Kitty Hawk in the South China Sea. The news media and pundits dramatized the incident as an example of China expanding its submarine operations, the Chinese government downplayed the reports as inaccurate, and the Pentagon said the media made too much of the incident.

“The bottom line is that […] they’re deploying them further and more frequently,” Defense News quoted an expert on the Chinese Navy at the National Defense University saying. China might even have a decisive submarine surge capability in 20 years, another pundit argued. “They are building a blue-water navy,” yet another expert warned. A politician in Taiwan thought it raises questions about “whether the U.S. in losing its military edge in the Western Pacific,” and commentators in both Taipei and Washington concluded that the incident showed that Taiwan needs to buy more submarines.

The Pentagon’s 2006 report Military Power of the People’s Republic of China stated that China was working on establishing a “first” or “second island chain” strategy for its naval forces, and that “Chinese forces have increased operations beyond China’s borders and coastal waters.” This may be the case for surface ships, but to illustrate the development the Pentagon highlighted “the highly publicized 2004 intrusion of a HAN-class nuclear submarine in Japanese territorial waters during operations far into the western Pacific Ocean.” DOD did not mention that the intrusion was one of only three patrols conducted by the entire Chinese submarine force in 2004, and that no patrols at all were conducted in 2005.

The U.S.-China Commission established by Congress after reports about Chinese spying, stated in 2006 that China is pursuing measures to try to “control” the seas in the Western Pacific, although “controlling” the seas is a daunting technological and operational task, and that China continues to “expand” its submarine force.

The Shrinking Chinese Submarine Fleet

Although China is modernizing its submarine force, it is not “expanding” it. Since the mid-1980s, the force has been in steady decline from nearly 120 boats to roughly 55 operational submarines today. The U.S. Navy expects the force will level out around 40 boats in the next decade.

The Shrinking Chinese Submarine Fleet

The Chinese submarine fleet has declined by approximately 50 percent since the mid-1980s, mainly due to retirement of old and obsolete classes. Construction of new classes is underway but is not anticipated to lead to an increase, as the U.S. Navy expects the fleet will level out at around 40 submarines in the next decade.

The decline of the submarine fleet is part of a transition where large older classes are being phased out and replaced with newer but less numerous submarine classes. The new submarines are more capable than the ones they replace, but the modernization has not resulted in an increase in the number of submarine patrols. On the contrary, during the period between 2000 and 2006, when China acquired a dozen new Kilo and Song class submarines, the number of patrols declined from six to two (with no patrols at all in 2005).


The implications of the low patrol rate are significant. The total operational experience for the entire Chinese submarine force is only 49 patrols in 25 years, corresponding to each submarine conducting an average of one patrol every third year.

As a result, Chinese submarine crews appear to have relatively little operational experience and consequently limited skills in operating their boats safely and competently. It suggests that the tactical skills that would be needed for the Chinese submarine force to operate effectively in a war may be limited.

China continues – at least for now – to use its submarine force as a coastal defense force.

Background: Chinese Nuclear Forces and U.S. Nuclear War Planning

4 thoughts on “China’s Submarine Fleet Continues Low Patrol Rate

  1. Z: I think anyone who read 2006’s news should know China only did 2 sub patrols in 2006:

    1. A Han SSN cruised to Guam then got followed back to home.

    2. A Song SSK stalked Kitty Hawk.

    For all the other time of the year, they had been sleeping.

  2. M: “The U.S. Navy expects the force will level out around 40 boats in the next decade.”

    Please provide a reference for this quote. It flies in the face of most estimates of the PLA(N) plans for their submarine construction. From here and here.

    You are correct that they are replacing older obsolete diesel submarines with more modern subs, both nuclear and diesel. They are also active in buying top of the line subs from Russia, and technology from other nations.

    Reply: Yes, there are many rumors out there, not all of which appear to be accurate.

    The reference is Worldwide Maritime Challenges published by the Office of Naval Intelligence in 2004. To get a copy, call their public affairs office at (301) 669-5670. Another more general guide is the Submarine Force Brief on the US Commander Submarine Force web site.

    The World Wide Web has many virtues, but one of its greatest dangers is that inaccurate information can proliferate and be repeated so often that it is seen as accurate. The high Chinese submarine numbers used by many private institutes and the news media might be inflated because they include submarines that float but are not actually operational. – MK

  3. S: I have two questions:

    1. Do you think that the US Navy is that good to track every Chinese sub on patrol? Maybe the Chinese are so smart that they just haven´t been discovered. Something stinks here.

    2. Well if the Chinese Navy is so inactive and lacking experience how do you explain the Song Incident?
    Doing nothing over the years and then suddenly sneaking undetected close into a carrier task force and surface and say hello to Uncle Sam. That is quite good for a coastal defense force, don´t you think?

    Greetings from Germany.

    Reply: Those are questions I would like the answers to myself. But there is no solid information in the public domain to answer either of them with confidence. So here are my subjective replies:

    1. Yes, if it tries then I think the US is capable of tracking every Chinese submarine on patrol. That’s not to say that tracking them is easy. For one thing, some of the Chinese diesel-electric submarines are quiet enough that they could be very hard to detect under the right circumstances. But a quiet submarine is not enough; it takes a skilled crew to make use of that capability for it to matter on a deployment.

    Another requirement is that the US continuously monitors each Chinese naval base, and that the US Navy has enough submarines in the area to track each submarine that leaves port. Of the 20 or so US submarines that are underway at any given time, about 12 are forward deployed on a specific mission. Some of these are tied down in the Persian Gulf and North Arabian Sea, so only a few are probably available to shadow Chinese submarines. In a US-Chinese crisis or war that priority would obviously change.

    2. As for the Song-Kitty Hawk incident, who knows? We don’t know very much about the circumstances. Yes it surfaced near a US carrier, but it was one of only two patrols that year. The rumor was that the Kitty Hawk was operating near Okinawa, and the US Navy said the carrier was not conducting anti-submarine operations at the time of the incident. We also don’t know if the US Navy was aware of the Song submarine’s presence in the area.

    What does tell us a lot about US capabilities in tracking Chinese submarines is this: Naval Intelligence is confident enough to state that there were no patrols in four years since 1981. That’s confidence! – MK

  4. DL: Your comments are very informative and its certainly begs the question as to why China is commonly demonised for being a danger to its neighbours?

    The puzzling question is:-

    Why would the PLA Navy spend such a huge sum of funds on acquring Russian kilo submarines and then not send the submarines on patrol to make its submarine force potent?

    It also make nonsense of India’s constant talk of denying the PLA navy the Indian Ocean. India wants to be a world power and is using China as a boogeyman to hide her real ambitions.

    Reply: Yes it begs a lot of questions. Only, keep in mind that the small number of patrols doesn’t mean that Chinese sibmarines are not doing anything at all. “Patrols” probably refer to longer voyages away from the Chinese coast. So it is possible that Chinese submarines, like that of its neighbouring countries, are busy training up and down the coast. They just don’t venture far away very often. The patrol data is a small window into their operations, but we just don’t know very much about it because the intelligence community is so tight-lipped about what’s going on, and the little it does reveal tends to be fed into threat warnings in support of defense posturing.

    China probably spends large sums of money (and here we also know very little in public) on its submarine fleet because it feels it needs to have some capability to counter the submarines and aircraft carriers other countries deploy off its coast. And here a potential Taiwan scenario is probably an important driver.

    It is true that it is hard to see what India has to worry about from the Chinese navy, but India is looking ahead 20-30 years and sees a growing Chinese capability. It may not mean a pending attack by any means, but India’s naval modernization is driven by a need to counter potentially hostile capabilities – plus a doze of national pride and ambitions to be a significant naval power in the Indian Ocean. MK

Leave a Reply

Your email address will not be published. Required fields are marked *