China's Anti Access Strategy: Submarine Force - Part I

Image 1: First and second island chains. Image Credit: DOD

Author's Note: As promised here is the greatly belated article I promised to you (from the poll), merry Christmas.


As a result of its continuing economic development, China's military is in the process of a major military modernization effort across all its armed services. The short term goal of this modernization program, up until 2020, to acquire the capability to deny access to the Western-Pacific up to the second island chain: Guam, Ogasawara island chain, and Indonesia. It is widely recognized that the People's Liberation Army (PLA) can already effectively conduct operations within the first island chain: Taiwan, Okinawa Prefecture, and the Philippines (O'Rourke, 2013). The People's Army Liberation Navy (PLAN) is arguably the center piece of China's island chain strategy and has consequently been a major beneficiary of increased PLA spending. Between 1995 and 2012, the PRC domestically produced 39 submarines and purchased 12 Kilo class diesel electric submarines from the Russian Federation. In total, the PLAN operates 53 diesel electric attack submarines, six nuclear powered attack submarines, and three nuclear powered ballistic missile submarines (Office of Naval Intelligence, 2009). ONI estimates within 10 to 15 years the PLAN submarine fleet will reach 75 boats. This trend is a concern for the United States as its own fleet of attack submarines is scheduled to drop to as low as 40 boats in the early 2030s and the US Navy maintains the position it needs at least 48 attack submarines to meet its current objectives (Rep. Forbes & Rep. Courtney, 2013). Chinese analysts have taken a keen interest in the "decline" of the USN:

"Chinese discussions of the American submarine force focus heavily on the continuing decline in its size. As one article from a People’s Republic of China (PRC) naval interest publication states, 'The decline of U.S. submarine strength is inevitable'...Rear Admiral Yang Yi, writing in 2006 on the future size of the American submarine force, quoted one American analysis as follows: 'China already exceeds [U.S. submarine production] five times over. . . . 18 [USN] submarines against 75 or more Chinese navy submarines is obviously not encouraging [from the U.S. perspective].'” - Gabriel Collins, Andrew Erickson, Lyle Goldstein, & William Murray, 2008.

This article will examine the objectives of the PLAN submarine force, its current composition and capabilities, and probable future trends within the PLAN with regards to its submarine force.

Strategic Objectives

Image 2: The main Chinese sea lines of communication (SLOC). Image credit: ONI, 2009.  

"Observers believe that China’s military modernization effort, including its naval modernization effort, is increasingly oriented toward pursuing additional goals, such as asserting or defending China’s territorial claims in the South China Sea and East China Sea; enforcing China’s view—a minority view among world nations—that it has the right to regulate foreign military activities in its 200- mile maritime exclusive economic zone (EEZ); protecting China’s sea lines of communications; protecting and evacuating Chinese nationals in foreign countries; displacing U.S. influence in the Pacific; and asserting China’s status as a major world power." - Ronald O'Rourke, 2013

While, the primary mission of the PLAN is to deny the US power projection within the first and second island chains, the PLAN has been tasked with other objectives in recent years such as protecting Chinese economic interests e.g. sea lines of communication (SLOC) and enforcing territorial disputes. SLOCs in particular represent a critical strategic vulnerability for China. For example,  82% of all China's seaborne oil imports cross through a single SLOC, the strait of Malacca (Department of Defense, 2012).

"It is along these strategic routes that the overwhelming majority of China's foreign trade-over 90 percent by volume and over 80 percent by value-is transported."  - Office of Naval Intelligence, 2009

In recent years China has become more assertive in its territorial disputes with its neighbors particularly with the Philippines, Vietnam, and Japan.

Image 3: Disputed territories in the Western Pacific. Image Credit: DOD

Due to their limited range, PLAN diesel electric submarines would be used to patrol major sea lanes and SLOCS within the first island chain in wartime. China's few nuclear attack submarines would most likely be used as intelligence surveillance reconnaissance platforms for areas beyond the first island chain given their superior range and endurance (Office of Naval Intelligence, 2009). The type 093 and the yet to be fielded type 095 attack submarines grant China a credible power projection capability beyond the first island chain.

Composition - Diesel Electric 

The PLAN submarine force is composed of mostly diesel electric attack submarines with varying degrees of technological sophistication e.g. the Ming class boats were originally designed in the 1950s. Despite the limited endurance (how long the submarine can sustain operations) and limited range of diesel electric submarines, they are considerably cheaper and technologically less demanding than nuclear powered submarines. The domestically produced Yuan and Russian Kilo class submarines are likely the PLAN's most capable diesel electric attack submarines. The Kilo class submarine has been widely exported and is operated by the Russian, Chinese, Vietnamese, Indian, Polish, Iranian, and Algerian navies. The PLAN operates four 877 models and eight upgraded 636 type Kilos. The 636 type Kilo is significantly stealthier and has a greater maximum range than the 877 type Kilo (Global Security, 2013). The 636 type Kilo is also capable of launching the SS-N-27 anti-ship cruise missile (Department of Defense, 2012). However, the effectiveness of the SS-N-27 is questionable.

Image 4: Kilo class submarine

The Russian imported Kilo class "inspired" many aspects of the subsequent Yuan (Type 041) class design. The Yuan will form the backbone of the PLAN diesel electric submarine force and is expected to be built in large numbers.

"The Yuan class has a tail with diving planes similar to those of the Type 039G, and a Kilo-style teardrop shaped hull with a raised hump on top. The Yuan has the raised decking/casing of the Kilo, the high freeboard and reserve bouyancy, a similarly-shaped bow (and torpedo tube disposition), but with the sail, propeller layout and stern section of the Song. It has also been suggested that the new submarine may be comparable to the improved variant of the Russian Kilo class (Project 636) in terms of size and general performance." - Global Security, 2013

Image 5: Yuan class submarine (Type 041)

Despite the US-European arms embargo put in place after the 1989 Tiananmen square protests, both the Yuan and Song class submarines feature 396 SE84 series diesel electric engines provided by MTU Friedrichshafen GmbH of Friedrichshafen (Lague, 2013). In addition to a reliable German engine, the Yuan is rumored to have air-independent-propulsion (AIP) capability as well (Global Security, 2013). As discussed in the "Implications of the Potential Russia-China Arms Deal" article, One of the inherent disadvantages to diesel electric submarines is the engine requires air for the engine to function meaning the submarine has to surface intermittently for air. While at the surface, the submarine is vulnerable to detection. The solution in older diesel submarines was to incorporate large lead batteries that could be charged by the engine; the use of these batteries would permit the submarine to function for a few hours without having to surface for air. Snorkels could also be used to feed the engine air while remaining under water but the submarine still had to remain fairly close to the surface. The next generation of diesel electric submarines incorporate greatly enhanced AIP capability which enables them to remain underwater for much longer periods of time (Whitman, 2001). AIP is most often achieved in modern diesel electric submarines with the addition of fuel cells (e.g. hydrogen-oxygen fuel cells). Depending upon the speed at which the submarine is traveling while AIP is activated, the AIP equipped submarine could remain submerged for more than a week as opposed to hours. As an added benefit, the use of fuel cells greatly reduces the noise generated by boat as the engine is not used for propulsion while AIP is activated.

Composition - Nuclear 

Image 6: Chinese type 094 ballistic missile submarines operating from the massive Yulin Naval Base located at Hainan island 

The PLAN currently operates four nuclear powered submarine designs, two attack submarine designs and two ballistic missile submarine designs. Of the two ballistic missile submarines, the type 094 Jin-class is significantly more capable than its predecessor, the Xia-class. The Xia is generally regarded as being "not a genuine deterrent capability" due to its large acoustic signature, primitive missiles, and poor performance (Erickson & Goldstein, 2006). Similarly, the type 091 Han-class attack submarine is largely obsolete compared to the type 093 Shang-class.   

Image 7 & 8: Relative acoustic signatures of Russian and Chinese diesel electric and nuclear submarines. The green area indicates submarines that would be relatively easy for the Navy to detect vs. red which would be difficult to detect. (Image Credit: Office of Naval Intelligence, 2009).


Generally speaking, Chinese nuclear submarines are significantly louder and less capable than their American and Russian counterparts.

"the 093’s noise level has been reduced to that of the Russian Akula-class submarine at 110 decibels. He states that the 094’s acoustic signature has been reduced to 120 decibels. According to this report, this is definitely not equal to that of the Ohio class, but is on a par with the Los Angeles. There is no additional information given to evaluate concerning the origins or comparability of these 'data.'" - Andrew S. Erickson & Lyle J. Goldstein, 2006.

As a reminder, a decibel is: "a unit used to measure the intensity of a sound or the power level of an electrical signal by comparing it with a given level on a logarithmic scale" - American English in Oxford dictionary, 2013.

Decibels do not scale linearly. A 3db change is signifies a doubling power and a change of 10 db signifies the power increasing by a factor of ten.  Therefore, the 636 Kilo class with an acoustic signature of 105 decibels is 10 times as loud as the 95 decibel acoustic signature of the Virginia class submarine.

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

The Shang has an acoustic signature similar to the original Russian Akula class boats or roughly equivalent to the original Los-Angles class submarine, not the 688I (improved Los-Angles class). Judging from acoustic signatures, the most modern Chinese nuclear submarines are comparabile to 1970s and 1980s US and Soviet designs shown on the chart below.

Image 9: US and Soviet/ Russian submarine acoustic signatures. Image Credit: Federation of American Scientists

The PLAN is expected to acquire a total of six Shang-class nuclear submarines to replace the ageing Han-class. The four type 093's under construction can be expected to include enhancements over the original model (O'Rourke, 2013). For type 095, see part II under future trends. 

Future trends of the PLAN submarine force and the recommended US and allied response can be expected in Part II. 

Sources

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