New UUVs: China's Plan to 'Attack from the Sea Floor'

by Lyle J. Goldstein

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The Achilles Heel of the Chinese Navy has long been undersea warfare. The Middle Kingdom’s nuclear submarines are considered noisy, with their “boomers” [SSBNs] only recently taking up what might loosely be considered an actual “deterrent patrol.” The diesel force was quite reliant on the imported Kilo-class from Russia until the last decade. Even if China could field quiet submarines with proficient crews, the geography is not very conducive to the extensive operation of submarines given the shallow bathymetry off of most of China’s coastal regions. The PLA Navy also lacks experience in hunting adversary submarines, since it is just now starting to field advanced fixed-wing and rotary-wing aircraft for that purpose. 

Yet, now these trends are starting to reverse and a whole variety signs are apparent (as occasionally reported in this regular Dragon Eye column for TNI) that the PLAN is now giving the undersea realm the priority it deserves for ambitious naval powers in the 21st century. A somewhat subtle, but nonetheless, important signal of that intention is the PLAN’s fielding of its very first large-size unmanned undersea vehicle (UUV), the HSU001. That vehicle was revealed during the 70th Anniversary Parade by the Chinese military on 1 Oct 2019. A reasonably detailed discussion of the vehicle appeared under the interesting title “Attack from the Sea Floor [从海底出击]” in the final 2019 issue of Shipborne Weapons [舰载武器], published by a CSIC research institute in Zhengzhou. Don’t get too excited, the article does not “reveal all.” But it is nevertheless worthy of closer examination and offers a number of potentially significant hints regarding coming attractions.

As is common practice for such articles concerning the most sensitive parts of China’s developing military power, this article begins with a lengthy discussion of competing of U.S. Navy systems. It notes in some detail the taxonomy elaborated in the U.S. Navy’s “Comprehensive Plan for UUVs” that was first published about the year 2000. It states that a more contemporary classification allows for both “super small type [超轻型],” as well as “super-large type [超大型]” UUV designs. The analysis assesses that two different American designs have been of great importance. First, it discusses the Penn State-developed Sea Horse [海马], which is credited with achieving a 500 nautical mile range and a five-day operating capability within the relatively large frame of 8.7 meters and weight of 4,500kg. A second effort that impressed the Chinese was the Manta [曼塔], which displaced 50 tons, had a top speed of 10 knots and was reported in this Chinese source to be capable of slinging Mark 48 torpedoes. Since observing USN developments in these foundational platforms, it’s not surprising that Beijing is monitoring American progress in fielding XLUUVs with more than a little interest. This article reports on a U.S. test of a UUV that navigated 1,000 nautical miles and they have noted that these designs can additionally be carried into battle by Virginia-class SSNs. It is also observed that the U.S. Navy will be ready to deploy large UUVs into combat by 2022.

As to the actual design of HSU001, not too many specifics are revealed in this article. For example, there is no given data (not even estimates) for length, width, weight, diving depth, speed, etc. Eye-balling available photos from the parade suggest a length of approximately five meters and a width of perhaps 1.5 meters. The design is described by this Chinese assessment as “sleek [光滑]” and it is described as resembling somewhat the Soviet Oscar-class (Type 949) nuclear submarine in its shape. It is also said to be quite similar to a German UUV design. The hull concept also has certain similarities concerning maneuverability with the Russian Harpsichord UUV. Compared to American large UUV designs, it seems wider and notably has dual shaft propulsion. The claim is made in this Chinese analysis that the design maximizes stability and should also reduce noise. It is suggested, moreover, that the design could accommodate externally mounted “torpedoes, mines, etc [鱼/水雷等].”

One of the most striking features of China’s first large UUV to be publicly revealed are the two very distinctive sensor masts. Interestingly, these masts appear not to be telescoping, but rather have reclining positions and fold down into the hull. This is most likely a cost saving feature. The forward mast is not as tall, but is substantially bulkier. It is said to house an “advanced electro-optical detection system [先进光电侦察系统],” as well as various underwater cameras. For underwater detection, predictably, sonar is said to be the “main tool.” But this mast does imply, as the Chinese analysis notes, that the HSU001 Chinese vehicle will be tasked with providing intelligence on surface, aerial and shore targets, as well as those underwater.

Concerning the rear mast, which is taller (perhaps over one meter), but thinner, this Chinese assessment says that is not an engine intake, but rather constitutes a communications mast. This indicates, according to the Chinese article, that HSU001 has the ability to “fight as part of a network.” Expanded to comprise “wolfpacks [狼群]” or “swarms [蜂群],” this appraisal claims the new vehicles operating in groups will provide enhanced deterrence, as well as strategic advantage, against China’s foes, as the new vehicle adopts new mission areas. And here is where the analysis of Beijing’s new UUV program gets rather interesting.

First, the analysis says directly that the HSU001 vehicle “attaches emphasis to seabed warfare capabilities [注重坐底作战能力].” Thus, it is pointed out that the vehicle is not especially large, but it has a simple structure and high reliability, enabling it to sit on the ocean floor for extended periods and blend in, while passively observing the surrounding environment. This capability, moreover, is mentioned as a way to cope with the power source issue that is a limitation on most UUVs. It is suggested that such quiet observation missions might go well over 30 days, expanding the PLA’s intelligence capabilities to the limits of the first island chain and even to the “second island chain [第二岛链].” 

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A second potentially troubling mission area of the HSU001 discussed in this article concerns “support for special operations [支援特种作战].” The analysis holds that a similarly configured U.S. vehicle can hold 6 frogmen (naval special forces) and operate for eight hours, perhaps working with some kind of “mother ship [母艇].” With “ample space,” as well as reliable communications, navigation and covert surveillance capabilities, the vehicle could attain an outsized role in PLAN amphibious warfare, including for a Taiwan scenario. In that respect, it is likely not coincidental that the same analysis emphasizes “Our country is now energetically developing its special operations capabilities [我国正在大力发展特种作战能力].”

A third mission area is said to be specifically concerned with rising tensions in the South China Sea area. Here, it is asserted that U.S. forces under the “excuse [借口]” of freedom of navigation patrols are actually threatening China’s strategic submarine bastion. Noting that that PLA surface forces have other priorities, such as training missions, it is also observed that these UUVs are particularly well suited for the ISR challenge in the South China Sea, since they are mostly impervious to weather (at least when fully submerged). They will have the long-endurance patrol capabilities to provide intelligence on adversary movements near Beijing’s reef bases in the South China Seas. Warning against enemy frogman activity, in addition to offensive and defensive mine warfare, are also missions mentioned in this context. 

The robot submarine (and unmanned surface ship) era is now nearly upon us. Chinese naval strategist have, moreover, stated explicitly that they intend to circumvent their long-recognized weakness in submarine warfare by cultivating undersea AI and by developing highly capable UUVs. A web photo of the 20 meter “Sea hound [海猎犬]” an XLUUV platform with certain design similarities to the large UUV discussed here, implies that HSU001 will indeed have many cousins.

Lyle J. Goldstein is Research Professor in the China Maritime Studies Institute (CMSI) at the United States Naval War College in Newport, RI. In addition to Chinese, he also speaks Russian and he is also an affiliate of the new Russia Maritime Studies Institute (RMSI) at Naval War College. You can reach him at goldstel@usnwc.edu. The opinions in his columns are entirely his own and do not reflect the official assessments of the U.S. Navy or any other agency of the U.S. government.