Beijing Confronts Long-Standing Weakness in Anti-Submarine Warfare

Publication: China Brief Volume: 11 Issue: 14

China's Oft-Criticized Z9

Observers of China’s naval development generally accept that Chinese anti-submarine warfare (ASW) remains an Achilles’ Heel of the otherwise highly methodical and quite remarkable evolution of Chinese maritime power.  While Beijing will soon be able to boast about its first aircraft carrier and continues to upgrade an already respectable array of lethal anti-ship cruise missiles (ASCMs), the Chinese fleet nevertheless remains acutely vulnerable to submarine attack.  The July 2011 issue of Xiandai Jianchuan [Modern Ships] ran under the cover story of “The ASW Crisis of China’s Aircraft Carrier,” suggesting Chinese naval analysts appreciate this weakness.  Moreover,  a Chinese Navy captain writing in the same journal demonstrated the PLA Navy’s concern with the U.S. Navy submarine force when he described the deployment of one of America’s newest nuclear attack submarines to the western Pacific as an “event of no small significance” for the regional security situation [1].

Symbolic of China’s major weakness in ASW, Beijing seems to have less than a dozen maritime patrol aircraft (MPA)—the ASW workhorse of most advanced navies.  No wonder the submarine market in East and South Asia has been so dynamic over the last decade, as smaller neighbors, such as Vietnam, and other regional competitors, such as Australia, reach for an answer to China’s naval buildup.  Based on recent Chinese naval writings, Chinese defense analysts are quite concerned about the challenge foreign submarines may pose to Chinese maritime interests and ambitions. Indeed, available evidence suggests China is laying the foundation for a considerably more advanced ASW capability that could emerge one or two decades hence.

Unconventional ASW Alternatives

At present, China’s most effective ASW tools might be termed as “unconventional,” in the sense that these are not necessarily the standard tools, such as the MPA capability highlighted above, that the leading navies have applied to the ASW problem.  However, mine warfare, already a strength of the Chinese navy, does give Beijing certain extant options with regards to ASW, especially given the shallow waters and constrained passageways that tend to characterize East Asian maritime geography.  Mine barriers could be used in defensive ASW operations, such as creating cordons for Chinese surface vessels and merchant traffic in proximate areas, such as in the Yellow Sea or the Taiwan Strait.  Chinese naval analysts also frequently discuss the use of offensive mine warfare against submarines [2]. Such operations could include deploying mines—perhaps even clandestinely using converted merchant vessels—into sea areas where hostile submarines might operate.  Historically, mines have threatened submarine operations [3].

Chinese sources also offer hints at how other unconventional operations could be used to implement ASW operations in the future.  For example, a senior Chinese naval officer at the Beijing Naval Research Center recently wrote that in the future unmanned underwater vehicles (UUVs) may be used to deploy sea mines—thus enhancing Chinese mine warfare capabilities for ASW [4].  Other Chinese sources have suggested mobilizing either fishermen or fisheries enforcement vessels into any prospective ASW fight.  In fact, one recent line drawing of a fisheries enforcement cutter, refit for war-time duty, shows the cutter equipped with an ASW helicopter, ASW torpedoes and a towed array sonar [5]. If future Chinese coast guard cutters—now being built in large numbers—are being designed to accept such upgrades before or during hostilities and thus play a role in an ASW campaign, that may indicate a new level of seriousness in China’s overall ASW effort.

Conventional ASW Options

While China has long deployed a large fleet of small displacement “sub-chasers” (Type 037), Beijing has lacked a modern ASW-oriented surface combatant, even as it has built both respectable air defense frigates (Type 054) and destroyers (Type 052) over the last decade.   An apparent indicator of ASW’s low priority is that the hull-mounted sonars in China’s new surface combatants, even on the newest hulls, are simply too small for long-range detection.  China’s towed sonar array program however may be more developed than was believed previously.    Towed array technology was apparently part of a sonar technology package that France exported to China in the early 1980s.  At the time, one or more Type 037s were reportedly equipped with towed sonar arrays.  If true, the Chinese Navy now has almost three decades of experience working with towed-array sonars in a limited experimental capacity, even if it is not fully proficient. The same source claims that China’s latest surface combatants are deployed with indigenous H/SJG-206 sonar suites, including towed arrays, that under some conditions could enable an approximate detection range of up to 100km—a standard comparable to surface combatants of the leading navies [6]. Towed sonar arrays have become one of the key technologies for modern ASW, because they can be deployed at considerable distance away from the ship and thus do not suffer the self-generated noise interference that plagues hull-mounted systems. 

A second, related major development is the high likelihood that China will deploy a modern ASW corvette in the coming years—discussed in the Chinese media as the Type 056 corvette.  According to one recent appraisal, its future dimensions could be about 90 meters long with an approximate displacement of 1,500 tons.  The armament of ASW torpedoes and rocket-thrown depth charges is not surprising and the sonar suite is unknown. The fact that it will almost certainly have both an embarked helicopter and a hangar to support the helicopter over extended periods suggests a major advance over Type 037, since helicopters are now considered the most important ASW defense deployed by surface vessels.  In overhauling the Type 052 destroyers with new ASW weaponry and sensors, the Chinese Navy also may take advantage of the fact that this older mid-1990s design actually has two hangars for helicopters.  Indeed, this overhaul also may demonstrate the PLA Navy’s enhanced commitment to ASW [7].

Observers have long considered naval helicopters a critical weakness of the Chinese Navy and an essential part of its ASW vulnerability.  Indeed, Chinese naval analysts have roundly criticized the Z9C, China’s standard ship-borne helicopter, as inadequate to the challenge of airborne ASW, primarily because it lacks the heavy lift capacity to carry on-board processors, sono-buoys and ASW weaponry.  The larger Z8 has adequate capacity, but is far too large to fit aboard most Chinese surface combatants.  Therefore, the Chinese Navy has had to settle for importing the Russian Ka-28 Helix in significant numbers.  While the Chinese Navy appears to have developed a new comfort level with this platform, they also realize that it also may not be the ideal ASW helicopter [8]. Nevertheless, China appears to be steadily improving its proficiency in ship-borne helicopter operations.  For example, naval helicopters have played an ever larger role in China’s anti-piracy operations in the Gulf of Aden and new roles are being explored seriously for Chinese naval helicopters, such as early warning and anti-surface missions.  A new level of professionalism also is evident in how Chinese pilots view and train for ASW [9]. Overall, a significantly improved Chinese naval aviation component will certainly influence the trajectory of Chinese ASW capabilities.

If questions have dogged Chinese naval helicopter development, the paucity of large, fixed-wing ASW aircraft is perhaps even more puzzling.  For other leading world navies, such as the Japanese Navy, the U.S. Navy or the Royal Navy, the MPA is a cornerstone of the ASW effort.  The chief advantage of the MPA for ASW is its great mobility, long loiter time, large payload and near invulnerability to submarine-deployed weaponry as well as the especially large search area they can cover.  Given these advantages, why has Beijing deployed just a handful of Y-8 MPA?  Actually, the answer could be hiding in plain sight: why build a platform that could not be adequately defended?   Since its founding, the Chinese Navy (and Air Force) could not realistically contend for air superiority in the “near seas” much less at greater distances from the homeland.   Over the last decade, the situation has changed, especially near China, and so MPA may now become a viable ASW platform.   Indeed, substantial speculation surrounds the eventual serial production of a new Chinese MPA with at least one design showing a radical departure from the Y-8, featuring ASCM launch capability and a large aerial refueling pod over the cockpit (similar to a UK Nimrod) [10]. While the Chinese Navy may depart from the U.S. Navy model in its MPA force structure, for example constrained by its lack of foreign bases to fly MPA missions over distant blue water zones, the problem is nevertheless recognized by Chinese naval analysts and it is possible that this gap will be at least partially filled in the coming decade with a new buildup once a design is finalized.  On the other hand, Beijing also could invest more heavily in unmanned airborne ASW systems as well [11].

Submarines also are invaluable for ASW—a mission set perfected during the Cold War.  Conventional wisdom has long held that the Chinese submarine force was optimized for anti-surface warfare and had little ASW capability.  The rather gradual development of the Chinese nuclear submarine force reinforced this view, because of the relatively slow search speeds that Chinese submarines could achieve in combat for the foreseeable future.  Nevertheless, diesel submarines might have some advantages in shallow littoral waters and China probably is perfecting air-independent propulsion for its diesel fleet, substantially enhancing their capabilities.  Moreover, a recent survey of Chinese ASW capabilities made the claim that the Song-class submarine in the mid-1990s carried China’s first heavyweight ASW torpedo as well as rocket-thrown ASW weapon (qianshe fanqian daodantermed ASROC in Western navies) [12]. If this report is true, it suggests ASW has been a mission set for the Chinese diesel submarine force from a relatively early point.  Chinese analysts also show a keen interest in submarine-deployed towed sonar arrays—another key ASW technology [13]. There are genuine reasons to doubt the proficiency of Chinese submariners in a direct contest with a hypothetical adversary’s submarines, such as those of the U.S. Navy, which gained invaluable experience over decades and put extraordinary resources behind submarine ASW during the Cold War.   Despite the disadvantage in experience, the employment of Chinese submarines for ASW cannot be dismissed entirely.  Chinese submariners also will have certain advantages, such as their probably greater familiarity with bathymetric and oceanographic conditions in the sea areas close to China.  Moreover, the Chinese submarine force understands the need to employ “asymmetric strategies” against adversary submarines, like the sea mines discussed above [14]. Finally, no navy is likely to have a monopoly on submarine ASW prowess, in part, because no such campaign has ever been fought, suggesting significant uncertainty will continue to surround this enigmatic yet crucial domain of future naval warfare.


For now at least, Chinese naval development remains weak in ASW.  It has been suggested, moreover, that China could simply ignore adversary submarines—their weapons load outs, while extremely lethal for the respective targets, are not especially large.  Moreover, ASW is an extremely expensive mission.  However, available evidence does not suggest either cost or technical challenges have dissuaded China from pursuing significant ASW capabilities.  To the contrary, the Chinese Navy appears to understand that a massive national effort will be required, entailing new platforms, training infrastructure and research efforts that go well beyond the scope of existing navy laboratories and institutes [15]. For Washington, the major implication of this research is that future undersea superiority cannot be taken for granted.  In that regard, the recent announcement that in 2030 the number of U.S. Navy nuclear attack submarines would fall below 40 is not at all reassuring [16].


1. Li Jie, “You wen shuixia helang sheng” [Once Again the Undersea Nuclear Wolf Can Be Heard], Xiandai jianchuan [Modern Ships], November 2010, p. 62.

2. Fu Jinzhu, “Shuilei zuozhan shiyong de N ge huanjie” [The N Link in Employment of Sea Mine Warfare],  Jianchuan zhishi [Naval and Merchant Ships] October 2008, pp. 60-63.

3. For example, eight U.S. submarines are thought to have been destroyed by mines in WWII.  “U.S. Submarine Losses – WWII” at

4. Li Jie, “Wu ren qianhang qi: neng chengwei haidi shashou ma?” [UUVs:  Can They Become the Assassin’s Mace of the Ocean Depths?] Dangdai haijun [Modern Navy], January 2010, pp. 63-65.

5. On deploying Chinese fishermen in the undersea battle, see Liu Wei, “Wei yingdui zhongguo  qianting: mei dali fazhan wu ren qianhang qi [“In Order to Cope with Chinese Submarines:  the United States is Energetically Developing UUVs”] Jianchuan zhishi [Naval and Merchant Ships], November 2010, pp. 58-61.  For the line drawing, see “Wartime Refit of FLEC 310” Jianzai wuqi [Shipborne Weapons], March 2011, p. 37.

6. Xiao Feizhu, “Jianting sheng na yu zhongguo haijun fanqian” [Warship Sonars and the Chinese Navy’s Anti-Submarine Capabilities] Jianzai wuqi [Shipborne Weapons], p. 37.

7. See photos, graphics and discussion of this refit on “PLAN Activity Outside of Varyag” July 3, 2011 at the website

8.Tian Ying, “Hangkong fanqian duidang qian zhongguo haijun de zhongyao yiyi” [The Vital Significance of Airborne Anti-Submarine Capabilities for Today’s Chinese Navy], Jianzai wuqi [Shipborne Weapons], March 2008, p. 52.

9. Xie Jing, “Mubiao: shuixia qianting, kai huo! caifang ren: hangkong fanqian zhuanjia, haijun hangkong gongcheng Qingdao fenyuan jiaoshou sun mingtai” [Target:  Submerged Submarine, Open Fire!  An Interview with Airborne Anti-Submarine Expert, Qingdao Naval Aeronautical Engineeering University Professor Sun Mingtai], Hangkong zhishi [Aerospace Knowledge] February 2008, p. 15.

10. Tian Yi, “Dui yun-8 gai zhongguo anji xunluoji de tantao” [Prospects for an Upgraded Y8 Land-Based Patrol Craft], Jianzai wuqi [Shipborne Weapons] January 2006, p. 25.

11. See, for example, abstract for Xu Teng, Zhuang Huaping, and Xu Jie, “jiyu wuqi xietong gongyong de wurenji fanqian zuozhan xiaoneng yanjiu” [Research on the Effectiveness of Anti-Submarine Wafare Using UCAV Based on the Cooperation and Sharing of Weapons], Zhihui kongzhi yu fangzhen [Command, Control and Simulation] (January 2008).

12. Chen Guangwen, “Bu sheng zhuo ying: zhongguo haijun fanqian zhanli de fazhan”  [Catching a Sound to Seize a Shadow:  Development of China’s ASW Combat Power] Jianzai wuqi [Shipborne Weapons], December 2010, p. 25.

13. “Focal Point:  Submarine Deployed Towed Arrays of Russia and the US] Jianchuan zhishi [Naval and Merchant Ships], August 2010, pp. 22-25.

14. Zhang Yunhai, “Shuilei xin shiming zhanwang” [Prospect of Sea Mines’ New Missions], Shuilei zhan yu jianchuan fanghu [Mine Warfare and Ship Self-Defense], Vol. 18, No. 1 (2010), pp. 1-2.

15. Yang Liping and Wu Zhimin, “Zhucheng fenxi fa zai hangkong fanqian jixing neng pinggu zhong de yingyong” [Application of Principal Components Analysis in Evaluating the Maneuverability of Typical Anti-Submarine Aircraft], Hangkong gongcheng daxue xuebao [Journal of the Air Force Engineering University], (April 2007), pp. 14-17.

16. RADM Michael Connor, “Investing in the Undersea Future,” USNI Proceedings (June 2011), p. 18.