It was the U.S. Navy’s biggest jolt in years. On October 26, 2006, a Chinese Song-class attack submarine quietly surfaced within nine miles of the aircraft carrier USS Kitty Hawk as the 80,000-ton-diplacement vessel sailed on a training exercise in the East China Sea between Japan and Taiwan.

The Song-class vessel, displacing 2,200 tons, was close enough to hit the Kitty Hawk with one of its 18 homing torpedoes. None of the carrier’s roughly dozen escorting warships detected the Song until it breached the surface.

The Song’s provocative appearance was, for the Americans, “as big a shock as the Russians launching Sputnik,” one NATO official told Britain’s Daily Mail newspaper, referring to the Soviet Union’s launch of the first-ever space satellite in 1957. “This could well have escalated into something that was very unforeseen,” said Adm. Bill Fallon, then commander of U.S. Pacific forces.

The incident underscored the then explosive growth of the People’s Liberation Army Navy’s undersea force, as well as Beijing’s apparent intention to wrestle the Western Pacific away from the once-dominant U.S. Navy. “The Chinese are building a credible submarine force which will make it very difficult for the U.S. Navy to maintain sea control dominance in or near coastal waters off of China,” warned Rear Adm. Hank McKinney, former commander of the U.S. Pacific Fleet’s submarine force.

Of particular concern to American defense officials was the projected introduction, over the coming decade, of up to 20 new nuclear-powered attack submarines, known as “SSNs,” that are an order of magnitude more capable than the Song class. “The acquisition of increasing numbers of SSNs would give it (the PLAN) the ability to contest U.S. naval forces farther from China’s shores,” Thomas Mahnken wrote in China’s Future Nuclear Submarine Force, edited by Naval War College professor Andrew Erickson and published in 2007.

Yet six years later, McKinney’s and Mahnken’s alarm has been proved false. The PLAN still possesses a tiny number of nuclear-powered submarines. The Songs and other short-range diesel boats remain the backbone of China’s undersea force. Beijing’s production of new submarines has declined and the PLAN’s overall undersea fleet is likely to contract in coming years. “I don’t think they know whether they want to make the full-up commitment it would take to do this (submarine) thing right,” Owen Cote, Jr., an analyst at the Massachusetts Institute of Technology, says of the Chinese.

Meanwhile, the U.S. Navy and its Pacific allies have crafted plans to stabilize or even grow their own submarine fleets. In 2006, Western observers feared the undersea balance of power in the Pacific would tilt. In a sense, they were right. It has tilted — back towards the United States and its allies.

How that happened speaks volumes about China’s evolution as a regional power.

Chinese Type 094 submarines in port. Google Earth image

Crunching the numbers

In early 2011, the PLAN possessed “more than 60 submarines,” according to the Pentagon’s Congressionally-mandated annual report on Chinese military capabilities.

That force included five nuclear-powered attack submarines: three of the 1980s-vintage Type 091 Han-class SSNs that are rapidly reaching the ends of their service lives, plus two Type 093 Shang-class boats. The next-generation Type 095 SSN is due to enter service around 2015, according to Pentagon estimates.

The PLAN’s diesel-sub fleet is much larger than the nuclear fleet: more than 50 in all, including 13 Songs, four of the newer Type 041 Yuan class, plus a dozen Russian-made Kilos. Obsolete Romeo- and Ming-class vessels round out the total for diesel boats.

Four or five experimental ballistic-missile submarines or “boomers” — all but one of them nuclear-powered — comprise the remainder of the PLAN undersea force. By comparison, in 2011 the U.S. Navy possessed 53 attack submarines, four guided-missile submarines and 14 ballistic-missile boats: 71 in all.

Just seven years ago, U.S. analysts predicted the Chinese submarine fleet would outnumber the American sub fleet by 2011. Writing in China’s Future Nuclear Submarine Force, Richard Fisher of the International Assessment and Strategy Center predicted the PLAN would have around 74 boats in 2010 — a figure at least a dozen higher than the real, current total.

Something happened between 2006 and 2011 that changed the calculus for the PLAN submarine force — and by extension for China’s regional aspirations. Actually three things happened: China stopped importing submarines, while also putting the brakes on domestic sub production; and the U.S. Navy successfully doubled its submarine production.

Moscow factored in the former changes. The purchase of a dozen Russian Kilos helped to boost the PLAN’s acquisition rate for submarines in 2005 and 2006. In both of those years, Beijing added seven submarines to its fleet, including seven Kilos overall.

But Russia is unlikely to resume supporting such a high rate of Chinese submarine acquisition, as Beijing is a potential strategic rival to Moscow — and since the Russian Navy’s own sub force is steadily declining to long-term levels of just a dozen each nuclear attack, nuclear ballistic-missile and diesel-attack boats. “There are powerful incentives for Russia to keep China just below its future submarine capabilities,” Fisher noted.

With an end to Russian imports, China must build all its own submarines. But here, too, Beijing relies on Russian assistance. As late as 2003, “Russia continued to be the main supplier of technology and equipment to India’s and China’s naval nuclear propulsion programs,” the U.S. Central Intelligence Agency reported.

The high rate of Chinese sub procurement in 2005 and 2006 justifiably drew the attention of Western analysts. But by using those years as their baseline, analysts often projected PLAN sub force levels that were unrealistically high.

From 2007 on, China acquired only domestically-built submarines, meaning the growth of the PLAN undersea force was constrained by the not inconsiderable limitations of the Chinese arms industry, which can’t function without Russian-provided engines and electronics — and which, even at the best of times, struggles with safety and quality control.

A possible case in point: in early August 2011, there were unconfirmed reports that a Type 094 boomer leaked radiation during work on its electronic systems in the port of Dalian, apparently prompting the PLAN to cordon off the area and crack down on media coverage of the alleged incident.

With the Kilo purchase complete, Beijing added just two boats in 2007, none in 2008 and two each in 2009 and 2010. It appears that, barring a major reversal of the current trend, the PLAN will acquire no more than two submarines a year over the medium term.

That’s the same submarine production rate as in the United States — though only recently. In the early 2000s, Washington purchased just one submarine a year, on average. A cost-savings initiative launched in 2005 drove the price of the current Virginia-class attack submarine down to around $2 billion apiece, allowing the U.S. Navy to purchase two Virginias annually starting in 2011.

U.S.-built submarines traditionally last up to 35 years, versus fewer than 30 for lower-quality, Chinese-built boats. With similar pre-existing force levels and identical production rates, the U.S. undersea fleet will level off at a higher level than the Chinese fleet will.

“Excluding the 12 Kilos purchased from Russia, the total number of domestically produced submarines placed into service between 1995 and 2007 is 30, or an average of about 1.9 per year,” wrote Ronald O’Rourke from the U.S. Congressional Research Service. “This average rate of domestic production, if sustained indefinitely, would eventually result in a steady-state force of domestically produced submarines of about 38 to 56 boats of all kinds, again assuming an average submarine life of 20 to 30 years.”

And that’s being optimistic. “It’s possible that the greater resources required to produce nuclear-powered boats might result in a reduction in the overall submarine production rate,” O’Rourke wrote. “If so, and if such a reduced overall rate were sustained indefinitely, it would eventually result in a smaller steady-state submarine force of all kinds.”

According to current Pentagon projections through 2040, the U.S. submarine fleet should never dip below 51 boats, with a peak of 73 in 2013 and 2014. And all of those boats are nukes — a not insignificant distinction.

Navy Secretary Ray Mabus visits a Chinese submarine during a visit to China in 2012. Navy photo

Sub versus sub

Even under the most favorable projections, the PLAN will possess just a handful of nuclear-powered attack submarines at a time over coming decades. China’s SSN fleet could actually decline in the short term, as the three ancient Type 091s are likely to leave service before an equal number of Type 095s are ready.

That matters because only nuclear-powered submarines, with their high endurance, are capable of true “blue-water” operations far from shore bases. It’s for that reason that all of the U.S. Navy’s submarines are nuclear-powered: Washington’s global military presence demands it.

To project power beyond its own coastal waters, Beijing needs nuke boats. The fact that China isn’t building large numbers of SSNs reflects either a lack of serious interest in a true, global naval presence — or an inability to back up grand military ambitions with working hardware.

China is left with an undersea fleet composed mostly of diesel attack submarines, which by virtue of their short range tend to be defensive in nature. “Current Chinese diesel submarines rarely deploy outside the first island chain (west of the Philippines) and essentially never deploy beyond the second (east of the Philippines),” Cote wrote. “Nor would these submarines be well-suited for extended deployments into the Pacific or Indian Oceans because of range and crew habitability constraints.”

Even as defensive weapons, China’s diesel submarines lack flexibility. For one, “the PLA has only a limited capacity to communicate with submarines at sea,” according to the Pentagon’s annual China report. Moreover, the PLAN’s subs are optimized for attacking surface targets such as U.S. aircraft carriers. Lacking the most sophisticated sensors and weapons, they’re far less useful for hunting U.S. submarines. “China has very limited (Anti-Submarine Warfare) capabilities and U.S. submarines are the most difficult ASW target in the world,” Cote wrote.

“Thus, China would have difficulty preventing U.S. submarines from operating in its shallow coastal waters,” Cote continued. That’s important because one of the American subs’ main tasks is to destroy enemy submarines. China’s undersea fleet cannot prevent the United States’ undersea fleet from hunting it down in its own home waters.

Considering the imbalance between large, sophisticated, ASW-optimized U.S. submarines and their smaller, less flexible, surface-attack-focused Chinese rivals, a census of the two nations’ undersea boats can create a false impression of near parity: 60 Chinese subs versus 70 U.S. ones. But if the American vessels can hunt the Chinese vessels almost with impunity, it almost doesn’t matter how many submarines Beijing possesses.

Even if numbers really did matter, the trends aren’t in China’s favor. Beijing might match the United States in submarine production rates, but it can’t possibly keep up with the combined sub acquisitions of Washington and its closest Pacific allies. Japan is in the process of adding six diesel attack boats to its current force of 16. Australia aims to double its fleet of six diesel boats. South Korea is also doubling its six-strong undersea fleet. Six years ago, Vietnam purchased six Kilos from Russia.

The Song submarine’s surprise appearance alongside the USS Kitty Hawk helped stoke fears of Chinese undersea dominance that were further fueled by a brief surge in PLAN sub acquisition. Today, with more U.S. and allied submarines entering service and fewer Chinese boats on the slipways, those fears — and the policies and assumptions they produced — warrant reconsideration. China isn’t building a world-class, globally-deploying submarine force. It’s building a mostly defensive, regional undersea force — and a smaller one than once predicted.

Originally published by The Diplomat.