China Has Built the Biggest and Baddest Conventional Submarine in the World

Sebastien Roblin

Security, Asia

A simple question: Why?

In 2010, China’s first—and only, so far—Qing-class submarine sailed out to sea following nearly six years of construction. Displacing 6,628 tons submerged and measuring exactly the length of a football field at one hundred yards long (ninety-two meters), it is by most accounts the largest diesel submarine ever built.

Unlike the vast majority of diesel submarines, the Type 032 can fire not only long-range cruise missiles, but submarine-launched ballistic missiles (SLBMs) with the capacity to send a nuclear warhead across the ocean.

Beijing prefers to keep its cards close to the chest, leading to speculation about the Type 032—is it purely a missile testing submarine, as is officially claimed, or is it the precursor of a fleet of low-cost ballistic-missile subs? Or was the Type 32 actually built as a prototype vessel for export to Pakistan?

In the past, nuclear submarines enjoyed an enormous advantage in submerged endurance and noise compared to traditional diesel submarines. A diesel submarine could swim quietly for days before having to resurface, but a nuclear-powered submarine can do it for months.

That China would even consider developing such a large diesel submarine is due to the advent of Air-Independent Propulsion (AIP) systems, which encompass a variety of technologies that allow engines and generators onboard a submarine to operate while consuming little or no oxygen. AIP systems can be even quieter than the reactors onboard nuclear submarines, and can efficiently propel the ship electrically for weeks, albeit only at slower speeds.

The first operational AIP powered submarine was the Swedish Gotland, which entered service in 1996. Using a Stirling engine, it could operate submerged for thirty days at a time. The small and nearly silent diesel sub successfully penetrated the antisubmarine defenses of U.S. aircraft carrier task forces in several war games.

Since then, China has built fifteen Yuan-class Type 039A (aka Type 041) diesel submarines using Stirling AIP technology, with another twenty planned. The torpedo-armed Yuan-class subs are intended, like the Swedish Gotland, to serve as stealthy short-range boats for stalking enemy vessels in coastal waters.

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