Key Point: Nuclear submarines could be a real threat for the U.S. Pacific fleet.
Early in 2015, a curious and disturbing report surfaced briefly and then disappeared—almost without a trace. The report, apparently published and then quickly retracted, had been posted by the French Ministry of Defense and concerned the successful operations of the French nuclear submarine Safir in an exercise pitting it against the U.S. Navy’s Theodore Roosevelt aircraft carrier battle group. The somewhat shocking content of the report—that the French submarine had succeeded in sinking “half the battle group” during the exercise—may explain its rapid purging from the internet. After all, close brothers in arms may demonstrate their tactical and operational prowess in a naval drill, but they should not gloat about that, and especially not in public, right?
The revelation that a U.S. Navy aircraft carrier group could be so vulnerable to a nuclear submarine did not make the mainstream media, and no mention was made by the many attentive defense analysts on this site, so it seems. However, the Chinese defense media does not miss much, especially concerning the capabilities of U.S. Navy carrier groups. In fact, a special issue of 兵工科技 [Ordnance Industry Science and Technology] (2015, no. 8) covered this “event,” featuring an interview with Chinese Submarine Academy professor 迟国仓 [Chi Guocang] as its cover story under the title: “A Single Nuclear Submarine ‘Sinks’ Half of an Aircraft Carrier Battle Group.”
Prof. Chi makes clear that he understands that “演习无法与实战相比 [an exercise can hardly be compared to real combat] and that, moreover, he evaluates U.S. Navy anti-submarine warfare (ASW) to be a “highly efficient” and “harmonized” system comprised of multiple layers of defense for an aircraft carrier. Yet, he concludes in the interview that the French report “有比较大的可信度” [has a reasonably high degree of credibility] and this edition of Dragon Eye will examine his logic in this respect, attempting to gain insights into emergent Chinese views on the utility of nuclear submarines in modern naval warfare.
At the outset of the interview, Prof. Chi asserts that submarines are the “克星” [nemesis] of aircraft carriers. He explains that over the course of World War II, no less than seventeen aircraft carriers were sunk by submarines. With another nod to the U.S. Navy’s prowess, Prof. Chi points out that eight of those seventeen were put down by U.S. submarines. Yet the historical episode that comes up repeatedly in the interview is not from WWII, but rather the Falklands War. This short, but sharp conflict from the early 1980s seems to have had an outsized impact on Chinese naval development, yielding Beijing’s singular and relentless focus on anti-ship cruise missile (ASCM) development. He demonstrates a very close study of that conflict, for example outlining the probable explanation for Argentine torpedo failures (complex and difficult hydrological conditions). He emphasizes the fact that the British nuclear submarine HMS Conqueror was able to track its prey, the General Belgrano, in that conflict over the course of fifty hours without detection before administering the coup de grace, as an example of the prowess of modern nuclear submarines. Yet he acknowledges that Argentine Navy ASW could not be compared to U.S. Navy ASW, of course.
So, the Chinese interviewer then asks bluntly: How is it that the French Navy was able to penetrate the formidable American ASW screen around the aircraft carrier USS Roosevelt, allegedly “sinking” the big deck and some of its escorts too? Prof. Chi offers many hypotheses with respect to this question, but focuses in particular on the small displacement of the French submarine. He observes that the Rubis-class submarine is the world’s smallest nuclear submarine (2,670 tons submerged) and that could make it more difficult to detect. According to this Chinese expert’s analysis, the Los Angeles-class submarines protecting the aircraft carrier have about three times the displacement—placing them at a disadvantage, especially in a circumstance where both crews have a similar level of training proficiency. This is not the first time that Chinese submarine experts have admired France’s small displacement nuclear submarines, which they seem to think could be particularly well suited for the shallow waters of the Western Pacific. It is argued in this Chinese analysis, moreover, that the French submarine’s comparatively slow maximum speed (25 knots) seems hardly to be a major deficiency.
Prof. Chi makes note of the comparative weaknesses of diesel submarines. In a related point, he explains that very significant U.S. air ASW assets are quite reliant on radar detections of submarines on or near the ocean surface. Against nuclear submarines, therefore, he concludes that the air asset ASW search is “如‘大海捞针’一样难” [as difficult as fishing a needle from the vast ocean]. Other points made in this Chinese analysis include the observation that the larger the battle group, the easier it is to track this more conspicuous target at long distances. Prof. Chi also notes that the employment of ASW weaponry can inadvertently aid a submarine’s escape following an attack, because the weapons may significantly complicate the acoustic environment, thus hindering searches for the attacking submarine.
Another possible explanation for the skillful (simulated) attack of the Safir might be the French commander’s capable use of naturally occurring complex hydro-acoustic conditions. Prof. Chi describes a long list of such conditions, including well known phenomena such as “convergence zones,” “sound speed gradients,” as well as the more mysterious “cold eddy” [冷涡] and “afternoon effect” [午后较应]. Likewise, the Chinese expert mentions that weather can be a major asset for a stalking submarine as it can significantly hinder the operations of surface and especially air ASW forces without significantly impacting undersea operations.
At the end of the interview, Prof. Chi is asked whether the Soviet nuclear submarine-centric model for naval development or the American aircraft carrier group-centric model is inherently superior. But the Chinese expert rejects the question as too simplistic. He says that Soviet Admiral Sergei Gorshkov wanted a “balanced fleet,” but Moscow’s efforts in the naval realm ultimately fell short of that aspiration. Meanwhile, the U.S. Navy, Chi contends, did succeed in this endeavor, so that the Washington’s fleet has “作战实力和能力无人能比” [combat power and capabilities without any peer] across all domains of naval warfare. It is likely positive from a deterrence perspective that Chinese experts have such esteem for American naval prowess, of course, but the article also illustrates how Chinese military analysts are diligently probing for cracks in the U.S. Navy’s armor, as they seek to develop their own naval capabilities that likewise cause “有人敬畏，有人怕” [people to admire and people to fear].
Lyle J. Goldstein is Associate Professor in the China Maritime Studies Institute (CMSI) at the U.S. Naval War College in Newport, RI. The opinions expressed in this analysis are his own and do not represent the official assessments of the U.S. Navy or any other agency of the U.S. Government. This first appeared in late 2015 and is being reposted due to reader interest.