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Jul 3, 2012 | 11:00 GMT

5 mins read

The Role of Submarines in the Western Pacific


Editor's note: Rim of the Pacific (RIMPAC), a multinational maritime exercise conducted every two years around the Hawaiian Islands, is being held June 27-Aug. 7. This year's exercises mark an important step in the projection of power and interoperability between participating nations as the United States begins its strategic shift toward the Pacific region, particularly with regard to China, the region's rising power, which was not among the 21 nations invited by Washington to participate. This series analyzes the naval capabilities displayed during the exercises and weighs them in the context of regional relationships. Click here for part one.

Submarines are uniquely suited for a wide range of operational contingencies, including sea denial, interdiction, mine laying, blockading and intelligence-gathering missions. A submarine's stealthy nature also makes it well suited for operating in heavily contested areas and for delivering special operations forces to enemy shores. With deadly armaments that can range from wake-homing torpedoes to anti-ship cruise missiles, submarines can stealthily approach much larger and costlier enemy vessels before striking a devastating blow.

Since the beginning of the 20th century, the submarine has offered world navies a cost-effective way to fight a stronger enemy fleet. Even navies that were effectively forced to maintain the bulk of their fleet at home due to a superior blockading force could resort to submarine warfare. For instance, during World War I, Germany was able to conduct an unrestricted submarine warfare campaign that nearly brought the United Kingdom to its knees.

Almost all of the maritime countries in the Western Pacific region have developed or are striving to acquire undersea capabilities. Indonesia and Vietnam, for instance, are working to expand their nascent submarine fleets. Taiwan is attempting to acquire new submarines but political considerations are hindering its ability to find an exporter.

The United States, China and Russia maintain the largest fleets of submarines in the Western Pacific region and are the only countries to operate nuclear-powered submarines in the region. Of the Western Pacific maritime nations, Japan, Australia and South Korea maintain the largest all-conventional submarine fleets. 


Largely because of concerns about the Chinese navy's growing capabilities, Japan's new defense policy, released in December 2010, emphasizes the need for a change from a post-World War II passive and reactionary defense posture to a more flexible and proactive force. The policy calls for an expansion of Japan's submarine fleet and outlines the role the vessels can play in conducting intelligence, surveillance and reconnaissance operations as well as operating regular patrols in the seas surrounding Japan.  

Japan currently operates a fleet of 18 diesel-electric submarines divided into three classes. The oldest is the Harushio class, of which only three of the original seven are still active. Of the three, two are used only for training. The Japanese also operate 11 larger Oyashio class submarines, the first of which was commissioned in 1998. Finally, the Soryu class, of which four are already commissioned and four more are slated to be built, is an upgraded and modified version of the original Oyashio equipped with air independent propulsion that allows diesel-electric submarines to stay submerged for much longer durations. These vessels are an integral part of monitoring major avenues of approach to Japan.

South Korea

The sinking of the South Korean Pohang class corvette Cheonan in March 2010, reportedly by a North Korean submarine, has only emphasized the role South Korean submarines can play in protecting the maritime approaches to South Korea from attacks by North Korean forces. South Korea's submarines play dual roles in this regard. They attempt to detect and monitor for hostile intent from any North Korean maritime vessel but also can be used for the stealthy insertion of special operations forces for sabotage or intelligence purposes.

Though primarily concerned with securing itself against the threat from North Korea, South Korea is seeking to expand its blue water capabilities by acquiring new vessels. South Korea's navy intends to improve its underwater warfare capabilities by steadily bolstering its nine German-built Type 209 submarines with at least nine more sophisticated and air independent propulsion-equipped Type 214 submarines. The South Korean navy already operates three Type 214 submarines and an additional six boats are expected before 2018, which would bring South Korea's total submarine force to 18.


The Australian navy's principle mission is to deny adversaries the use of Australia's maritime approaches while ensuring unimpeded trade to and from the Australian mainland. Seaborne trade is Australia's economic lifeline; more than 75 percent of its exports and imports (by value) travel by sea. While Australia depends on the United States to secure global sea routes, the navy wants to expand its capabilities in the immediate maritime approaches to Australia by upgrading some of its current ships and fielding new vessels.

The submarine, as a particularly cost-effective platform, theoretically is an excellent fit for Australia's needs. However, the country's submarine force has encountered substantial problems. In June 2008, there was a shortage of 37 percent in the number of submariners, and Australia's fleet of six Collins class vessels has been plagued with mechanical problems. The difficulties with the Collins class vessels and the perception of an encroaching China have made the need for a new submarine fleet the subject of governmental and public debate. Australia currently plans to acquire 12 conventional submarines within the next 15 to 20 years.

Japan, South Korea, Australia and other seafaring powers in the Western Pacific — including China and the United States — have different doctrines based on their specific interests and geopolitical positions. Yet the submarine plays a pivotal role in all these countries' military strategies. As a versatile and cost-effective platform that is useful in numerous contingencies and operations, the submarine will continue to figure prominently in the naval modernization efforts of East Asian maritime powers.

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