China's sail-less mini-sub a new menace for Taiwan

Asia Times

05-02-2025

China's unveiling of a sleek, sail-less mini-submarine signals a bold leap in stealth warfare. At the same time, it raises questions about the vessel's value in a potential Taiwan blockade and whether sheer quantity can outweigh quality concerns in undersea combat.
This month, Naval News reported that China has just unveiled a new type of submarine spotted at the Guangzhou Shipyard, a facility unknown for submarine construction.
The vessel features a distinctive, ultra-modern design with large X-form rudders and no sail. This development, revealed through satellite imagery, underscores China's ability to build submarines in secrecy, contrasting with the transparency of Western naval projects.
The submarine, approximately 45 meters long and 5 meters wide, differs from the Type 041 mini nuclear submarine and the 'Olympic' mini-submarine.
Its design suggests it could be an extra-large uncrewed underwater vehicle (XLUUV), potentially the world's largest, or a crewed vessel optimized for shallow water operations.
China is known to have built a sail-less mini-submarine in 2018, although that unit appears to be larger at an estimated 50 meters long and has no torpedo tubes, suggesting it may be a test prototype.
The absence of a sail, the presence of torpedo tubes and a possible towed sonar array indicate advanced stealth and combat capabilities.
Removing the traditional sail from a submarine minimizes its radar and sonar visibility. It also lowers its profile to reduce hydrodynamic drag, turbulence and noise while enhancing its speed and operational efficiency.
Further, using large X-form rudders boosts maneuverability, providing agility and stability for navigating complex underwater environments while supporting stealth.
Regarding armament, China's new submarine features torpedo tubes for engaging enemy vessels and potentially housing missile launch systems against surface and land targets.
It may also be capable of minelaying to disrupt enemy navigation, supply routes, intelligence, surveillance, reconnaissance (ISR) and insert special forces into Taiwan's frontline islands of Kinmen and Matsu or on secluded beaches on the main island.
Small submarines like China's new model may confer operational advantages in the Taiwan Strait, which is almost less than 150 meters deep and 180 kilometers across.
In a December 2023 Proceedings article, William Toti mentions that the Taiwan Strait restricts submarines' ability to maneuver vertically, making them more susceptible to detection and attacks, complicating evasive actions and limiting the effectiveness of traditional submarine tactics.
Further, the strait's narrowness positions submarines close to anti-submarine warfare (ASW) assets, heightening detection risks amid escalating naval capabilities and military exercises.
Despite those constraints, small submarines thrive in shallow waters thanks to their stealth, agility and ability to merge with seabed clutter, says Liborio Palombella in a June 2024 Naval Review article.
Palombella states that the reduced size of these submarines results in quieter acoustic signatures, allowing them to evade sonar detection while enabling close navigation to the ocean floor and improved maneuverability in narrow waters.
He mentions that this stealth and agility offer a considerable tactical advantage over larger conventional submarines, which find operating effectively in environments such as the Taiwan Strait challenging.
Further, small submarines may cost less to build than larger models, increasing the number of undersea threats without the cost of larger vessels. China's massive shipbuilding base lends itself to the maxim that 'quantity has a quality of its own.'
Sarah Kirchberger, in a September 2023 China Maritime Studies Institute (CMSI) report, says that China's submarine industrial base has significantly modernized, enabling larger-scale production of conventional submarines, particularly at the Wuchang and Jiangnan shipyards.
Kirchberger says China's investments in modular construction, advanced shipyard expansions and integration of military-civil fusion strategies have enhanced output.
However, she notes that weaknesses in propulsion systems and submarine quieting remain, limiting China's ability to match Western and Russian designs. However, she notes that closer ties with Russia may help China bridge these gaps.
China's new small submarine, along with its larger conventional and nuclear-powered ones, may play a critical role in a possible blockade of Taiwan to starve the self-governing island into submission.
In an August 2024 report for the Center for Strategic and International Studies (CSIS), Bonny Lin and other writers mention that China could use submarines to blockade Taiwan by deploying them to lay sea mines at the entrances of Taiwan's major ports, disrupting maritime traffic.
Further, Marek Jestrab mentions in a December 2023 Atlantic Council paper that to make a warning, Chinese submarines could covertly attack Taiwanese-owned merchant vessels sailing through the South China Sea and then deny involvement in the attack.
Such an action, Jestrab says, could swiftly sink the target and instill fear in the shipping industry due to potential losses and risks.
However, China's rapid submarine production may lack the rigorous quality assurance standards of the US Navy's SUBSAFE program, raising concerns about reliability and survivability.
The US Department of Defense's (DOD) 2024 China Military Report mentions that despite the ongoing retirement of older hulls, China's submarine force is expected to grow by 65 units in 2025 and 80 units in 2035, thanks to a massive increase in construction capacity.
This issue was underscored by reports of a possible pier-side sinking of a Type 041 nuclear-powered submarine in June 2024, highlighting potential design, construction or maintenance flaws.
The same concerns may extend to China's mass production of small, conventionally powered submarines, which, though produced in large numbers, may suffer from similar oversight gaps.
Moreover, China still has to account for Taiwan's ASW capabilities. For maritime domain awareness (MDA), Ian Easton and Randall Schriver mention in a December 2014 report for Project 2049 that Taiwan is believed to have a network of seabed sonar listening posts co-developed with the US.
Easton and Schriver say these posts are similar to the US SOSUS system, covering Taiwan's northeast coast up to the Senkaku Islands and its southern coast up to the Bashi Channel to the Philippines.
According to them, these underwater sensors are linked to the US Navy and Japan Maritime Self-Defense Force (JMSDF) for tracking ship and submarine movements through the First Island Chain.
Taiwan is also building an ASW fleet, with plans for six ASW frigates and an indigenous submarine force. Its first submarine, the ROCS Hai Kun, is undergoing testing and seven units will be built.
As China ramps up the construction of stealthy new mini-submarines, the real test isn't just numbers—it's whether these vessels can evade Taiwan's defenses and the US' ASW capabilities and survive the fast-evolving realities of modern undersea warfare.