A US Diesel Submarine Renaissance Would Be a Boon for Taiwan Navy

A US Diesel Submarine Renaissance Would Be a Boon for Taiwan Navy

A US Diesel Submarine Renaissance Would Be a Boon for Taiwan Navy

America’s naval expansion could constitute Taiwan’s opportunity.

President Donald Trump went on record last year favoring a 350-ship US Navy. The US Navy (USN) itself has called for a 355-ship fleet, and has commissioned three “Future Fleet Architecture” studies to postulate different visions of the fleet’s shape and size. The navy leadership is now pondering the competing studies, formulated by the Navy Staff, the Center for Strategic and Budgetary Assessments, and the MITRE Corporation. After weighing the analyses’ respective merits, the naval leadership will compile an official recommendation to inform congressional deliberations.

The common denominator among the views voiced thus far is the belief that the US Navy needs more ships, aircraft, and armaments. Assuming lawmakers go along with the Trump administration’s eventual proposal, the Navy will bulk up by roughly one-third from today’s 275-ship force. To make the budgetary figures work out, fleet designers will place a premium on affordable yet lethal platforms that can be procured in great numbers.

Diesel-electric submarines comprise one such platform—as the MITRE report emphasizes. MITRE representative Sunoy Banerjee put the idea to the US House Seapower and Force Projection Subcommittee earlier this month: “our thought was, base them forward—base them in Guam and Japan or in the Baltics—so they are close to the fight … this is a way of actually increasing the size of the submarine force relatively cheaply—because our back-of-the-envelope math suggests you can get three diesels for the cost of one Virginia,” referring to the US Navy’s state-of-the-art Virginia-class nuclear-powered attack subs.

Washington might do even better than that: the price tag for Japan’s Soryu class, widely heralded as the world’s finest large diesel sub, comes to almost exactly one-fifth that of a Virginia-class boat. Going this route would suggest a strategic vision for Asia: the US and Japanese Navies could create a combined fleet of Soryus (or some other common hull, perhaps a Soryu derivative), station them permanently in Japan under a combined command, and make them the nucleus of an island-chain defense force. That would reassure Japan, other allies, and other friends that America is in Asia to stay. And it would telegraph a powerful signal to China about allied fortitude and prowess.

To deter Beijing from aggression, that is, the allies must menace its capacity to use the China seas and Western Pacific. Since the 1950s, Japanese submariners have made themselves expert at regulating east-west movement through the straits piercing the first island chain, as well as north-south movement along the Asian seaboard. Think about what a larger US-Japanese force employing such tactics could do.

This is where Taiwan comes in. If American and Japanese shipbuilders jointly manufactured a diesel sub design for the US Navy and Japan Maritime Self-Defense Force, why could it not manufacture eight more boats for the Taiwan (ROC) Navy? The George W. Bush administration offered Taipei eight diesel boats back in 2001. Yet, industrial capacity worries came into play. No American yard has constructed diesel-driven subs since the 1950s, and no foreign government was prepared to incur Beijing’s wrath by transferring such a craft. That, plus the vagaries of Taiwan’s domestic politics—mainly KMT stonewalling of Democratic Progressive Party (DPP) president Chen Shui-bian’s initiatives in the Legislative Yuan—relegated the deal to limbo.

This could be a unique moment to rescue the deal. China has erred. Its overbearing conduct in the East and South China Seas may be overcoming governments’ reluctance to peeve the Voldemort of Asian politics. Consider how the political stars have aligned: China is giving Asian countries reason to make a common cause. An administration devoted to rebuilding US naval might has taken office in Washington, where the president’s party also holds Congress. A government determined to restore Japan to the ranks of normal states holds power in Tokyo. Both the presidency and the legislature in Taiwan are now under DPP control in Taipei. Accordingly, proposals dismissed not long ago as whimsical for political reasons might get a fair hearing in allied and friendly capitals, as well as in Taipei itself.

To be sure, there are no guarantees that a combined fleet will soon be roaming the deep. Even if Washington and Tokyo agreed on the principle, myriad details would remain to be sorted out—what design to use, where the boats would be built, and so forth. Sorting them out could slow the process of fielding a combined fleet.

The US Navy, furthermore, could oppose any procurement of diesel subs, and thus indirectly scuttle any arrangement with Taiwan. That the US “silent service” should be an all-nuclear force has been an article of faith among submariners for decades. And lawmakers might view relatively cheap conventional submarines as a substitute—rather than a supplement—to the nuclear-powered fleet. Submariners, consequently, might view them as a threat to the acquisition of nuclear boats.

In light of such impediments, Taiwan must press ahead with President Tsai Ing-wen’s recently announced plan to design and build eight boats at Taiwanese yards. Cultivating multiple options only makes sense for Taiwan’s navy.

How would the ROC Navy use a subsurface contingent after acquiring one? Consider maritime strategy from local, then regional viewpoints: From the micro perspective, Taiwan’s armed forces need to deter Chinese aggression. A modern eight-boat contingent would advance that goal substantially. Today, the Taiwan Navy’s undersea flotilla consists of two Dutch-built boats of 1980s vintage and two World War II-era antiques that are no longer combat-capable. Indigenous Taiwanese subs remain years off at best, especially since this represents Taiwanese shipbuilders’ first foray into undersea warfare. Multiplying the number of battleworthy boats by four—and doing so sooner than Taiwan could on its own—would open new tactical and strategic horizons for naval commanders.

Considering the rigors of maintenance, overhaul, and crew training, a navy operating close to home can count on having roughly half its vessels ready for action at any time. With four subs ready for sea rather than one, Taiwan’s Navy could dispatch patrols outside the Taiwan Strait while still guarding the Strait against a People’s Liberation Army (PLA) amphibious assault. It could mount a forward defense off mainland seaports. It could even free up an enterprising skipper or two of those four to make trouble for Chinese shipping wherever they saw fit—and, by sowing uncertainty in Chinese minds, bolster prospects of deterrence.

In short, Taiwan could replicate China’s “anti-access/area-denial” (A2AD) strategy in the island’s nautical environs, ratcheting up the costs to China of aggression against the island—and it should! The logic of anti-access will work on Taipei’s behalf in maritime Asia, just as it works on Beijing’s behalf throughout the Western Pacific. Turnabout is fair play.

Now, the macro perspective: While it remains doubtful the allies will fully integrate their battle strategies with Taiwan’s, fielding a common submarine type up and down the first island chain would enhance the navies’ capacity to coordinate their endeavors while waging war separately. Common hardware, tactics, and methods for war in the depths—including communication hardware and methods—would help submariners work together quietly. For instance, knowing whose subs were prowling where would help navies manage their efforts in crowded waterspace. Assuring friendly navies assail hostile shipping while avoiding fratricide is no small thing.

Countless factors—an outcry within the United States against buying foreign military merchandise, inertia within the nuclear-only US submarine force, lingering worries about what China might do, and on and on—will work against a diesel-centric multinational fleet. But such a venture makes sense on the operational, strategic, and political levels; its day may have come.

The main point: China is giving Asian countries reason to make a common cause. American and Japanese shipbuilders should jointly manufacture a diesel sub design for the US Navy, Japan Maritime Self-Defense Force, and Taiwan Navy. Proposals dismissed not long ago as whimsical for political reasons may now get a fair hearing in allied and friendly capitals.