China’s Undersea Threat: How Its Submarines Would Fight in a Taiwan War

Key Points – China’s People’s Liberation Army Navy (PLAN) possesses a large and expanding attack submarine fleet, comprising six nuclear-powered boats (SSNs) and 48 diesel-electric submarines (SSKs), 21 of which have Air-Independent Propulsion (AIP).

-While many older diesel boats are considered loud and less capable, the more modern Shang-class SSNs (some with VLS for YJ-18 anti-ship missiles) and Yuan-class AIP SSKs pose a growing threat.

-The primary mission focus for these submarines, particularly those armed with cruise missiles, appears to be supporting a potential amphibious operation against Taiwan by degrading its defenses.

-Though currently more defensive, future production of advanced SSNs could significantly enhance China’s undersea offensive capabilities.

Should We Worry About China’s Attack Submarine Fleet

China is known for its burgeoning aircraft carrier force. These three operational carriers usually get more media attention. And don’t forget that huge supply of carrier-killing anti-ship missiles—these are a threat to be reckoned with. The US Navy knows that China can execute its maritime anti-access/area denial strategy with great effectiveness. One aspect of the People’s Liberation Army Navy (PLAN) is its growing submarine fleet. The PLAN has six nuclear-missile “boomer” submarines, which is a concern as the country continues to improve its nuclear triad each year.

What It Lacks in Modernization the Force Makes Up for In Numbers

But the real numbers are in attack submarines. The PLAN is equipped with six nuclear-powered fast attack boats and 48 diesel-electric attack submarines. Twenty-one of these are equipped with the modern and stealthy air-independent propulsion system. The PLAN aims to increase its total submarine fleet from 54 to 65 in the coming years.

The PLAN uses its attack submarines to protect the homeland, as hunter-killers to eliminate enemy boats and warships, and to bombard the enemy coastline with missiles. These are straightforward capabilities that the United States and Russia also have.

That’s why the Chinese attack submarine force is not a huge advantage for Beijing. But PLAN admirals are satisfied that they can bring the fight to the enemy when needed and tie up American subs who would typically be cruising the South China Sea and the Taiwan Strait with ease.

Indeed, Taiwan would be the primary target for a potential Chinese submarine attack that I’ll describe later in this article.

Will Playing Defense Be Sufficient?

However, this should be considered more of a defensive group of subs rather than an offensive one. PLAN sailors on submarines have no combat experience. They have only executed operations in notional military exercises and drills. Many of the boats in the fleet assuredly can spot and track US warships, but most of the diesel-electric subs are old, loud, and clunky. The ones with air-independent propulsion systems are better but not enough to dominate the undersea fight against the US Navy’s stealthy nuclear-powered fast attack boats and cruise missile launching subs.

Shang-Class

The best Chinese submarines are the Shang-class nuclear-powered attack boats. They are quiet and have a new vertical-launch system for missiles. There are three upgraded Shang-class subs equipped with YJ-18 anti-ship ballistic missiles, and they can reach speeds of 30 knots underwater. There is also a new variant of the Shang class that is focused on launching land-attack cruise missiles. These could be able to sneak up on the enemy and fire guided missiles at US bases in Guam, South Korea, and Japan if needed.

Yuan-Class

China also features 21 Yuan-class diesel-electric attack subs. These are 254 feet long. The Yuan-class boats can only move at a top speed of 20 knots. They have updated torpedoes and anti-ship missiles. What sets the Yuan class apart is the Stirling generator-type air-independent power system. This allows the Yuan-class to conduct more extended patrols and maintain quiet movement, making them much better at tracking American shipping.

Kilo-Class

Another group of attack subs is the Kilo-class. China bought 12 Kilo-class boats from Russia, and these are older and less stealthy than the Yuan-class. The Russian-built Kilos are known as Project 636, and the improved version, also from Russia, is called Project 636M.

Many times Western experts refer to these submarines as the ‘black hole’, as they have been noted for being quiet and stealthy, despite their age.

The United States is not that worried about the Kilos. These are primarily for coastal defense and not for Blue Water patrolling. They are equipped with missiles that can be launched by torpedo tubes. The Kilos also come fitted with VA-111 Shkval super-cavitating torpedoes.

Song-Class

An arguably better PLAN attack sub is the Song-class diesel-electric. These are 245 feet long with a 22 knot top speed. This Song class is a homegrown, indigenously developed sub that built upon Russian technologies and improved them. Song-class boats have a modern, teardrop-shaped hull. Four rudders and a single propellor are on board. The engine has noise absorbers and rubber tiles cancel out sound. The Song-class can fire guided missiles and cruise missiles.

Ming-Class

Finally, there is the Ming class. These are diesel-electric vessels that are 249 feet long and capable of reaching only 18 knots. The Mings have 533mm torpedo tubes and cruise missiles can be fired from these tubes. The Mings are Cold War-era boats and not that noteworthy. They will probably go into reserve duty soon and are only suitable for protecting China’s shoreline.

I’m not that impressed with the Chinese fast attack force. The nuclear-powered boats are good, and the Chinese have come a long way from the old Ming-class. They had to base their diesel-electric force on Russian designs. The boats that can fire cruise missiles are the ones to watch. These would be instrumental in an attack on Taiwan. This is China’s primary mission with all of its attack subs that can fire guided missiles – prepare for an amphibious operation against Taiwan. The subs would lead a shock-and-awe campaign against Taipei to break the Taiwanese will to fight. Targets would be radar, surface-to-air missile defenders, and command and control facilities. This would blind Taiwan and prepare the aerial battlefield with follow-on attacks by Chinese fighter jets and bombers.

China will continue to produce nuclear-powered attack subs with improved cruise missiles. Modern boats will be more challenging to detect and track. Plus, they could sneak up on US shipping and even finagle their way past the protective screen of American carrier strike groups for a decisive attack.

Should the U.S. Navy Worry? 

The US Navy will be concerned most with Chinese cruise missiles. Many of the diesel-electric subs are loud and easy to discover. The Chinese have sufficient numbers to protect the coastline, which makes their fast-attack sub-fleet more suited for defensive rather than offensive missions. This doesn’t mean the Chinese sub-fleet should be ignored. Naval intelligence is quite aware of the strengths and weaknesses of PLAN subs. One thing we know is that China is an expert at producing new ships, and it will focus on building additional modern nuclear-powered submarines in the coming years. Those numbers could transform the force into something to be reckoned with.

About the Author: Dr. Brent M. Eastwood

Brent M. Eastwood, PhD is the author of Don’t Turn Your Back On the World: a Conservative Foreign Policy and Humans, Machines, and Data: Future Trends in Warfare plus two other books. Brent was the founder and CEO of a tech firm that predicted world events using artificial intelligence. He served as a legislative fellow for US Senator Tim Scott and advised the senator on defense and foreign policy issues. He has taught at American University, George Washington University, and George Mason University. Brent is a former US Army Infantry officer. He can be followed on X @BMEastwood.

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