A newly spotted Chinese submarine with an advanced rudder design signals China’s rapid advancements in submarine technology, potentially shifting the balance of power in underwater warfare vis-à-vis the US.
Last month, The War Zone reported that a Chinese submarine featuring an innovative X-form rudder has been identified at the Wuchang Shipyard in central Wuhan.
The War Zone mentions that the discovery was made by Tom Shugart, a retired US Navy submarine warfare officer and adjunct senior fellow at the Center for a New American Security (CNAS), who analyzed satellite imagery from this April.
The report says the images revealed the new Chinese submarine and a Hangor II class submarine being constructed for Pakistan. It notes that the new vessel appears significantly longer than the existing Type 039A Yuan class submarines, with an estimated length of 272-279 feet and a displacement of approximately 3,600 tons.
The War Zone report suggests that the extended hull could accommodate vertical launch system (VLS) cells, a feature rare in conventionally powered submarines but seen in other nations’ fleets, such as Israel’s Dakar class and South Korea’s Dosan Ahn Changho class.
As for the X-form rudder, the report says the design enhances maneuverability, efficiency and safety, and reduces acoustic signatures, making it particularly suitable for operations in littoral areas like the contested South China Sea.
China’s X-form rudder submarine may mark an evolution in its conventional submarine design, which is based on the Yuan-class SSK. It has previously introduced an angled sail design, which reduces detectability against active sonar.
China has been steadily advancing its underwater warfare capabilities, with conventional submarines being a significant area of focus.
The US Department of Defense’s (DOD) 2023 China Military Power report notes that the People’s Liberation Army-Navy (PLA-N) operates a mix of nuclear-powered ballistic missile submarines (SSBNs), nuclear-powered attack submarines (SSNs) and diesel-powered/air-independent attack submarines (SSKs).
It says the PLA-N submarine fleet is anticipated to expand considerably, with estimates suggesting an increase to 65 units by 2025 and 80 units by 2035. The report attributes this growth to China’s growing submarine construction capacity and the introduction of advanced anti-ship cruise missiles (ASCMs) on conventional submarines.
Further, Sarah Kirchberger says in a September 2023 China Maritime Studies Institute (CMSI) report that China persists in developing conventional submarines with advanced Air-Independent Propulsion (AIP) systems despite China’s capability to build nuclear submarines.
Kirchberger assesses that the rationale behind this strategy is rooted in the geographical challenges posed by China’s littoral waters, which are more navigable for smaller, quieter submarines operating in an area denial role.
She says that AIP technology is particularly advantageous in these environments, enabling conventional submarines to operate more effectively against adversaries’ sophisticated anti-submarine warfare assets, such as those of the US and Japan.
Kirchberger highlights China’s commitment to enhancing its submarine fleet’s endurance and stealth, with AIP systems providing a critical edge in China’s littoral waters.
She says that China’s focus on conventional submarine development, despite the availability of nuclear options, reflects a strategic approach tailored to the unique operational demands of China’s maritime environment.
Edward Feltham mentions In an October 2023 paper for the Naval Association of Canada that Chinese conventional attack submarines (SSKs) would be primarily used to defend Chinese maritime approaches, likely through a sea denial strategy employing torpedoes and anti-ship cruise missiles (ASCMs).
Feltham says that China can deploy its SSKs to maintain control over the Taiwan Strait and fend off any hostile attempts to impede Chinese forces.
However, Feltham points out that an SSK’s limited speed is a significant factor in China’s calculations. He says that while SSKs can maneuver quickly for a short time, that ability is limited to several hours due to battery capacity and maximum recharge rates.
While he says China can deploy SSKs outside its territorial waters, their transit time is longer than SSNs, reducing the time SSKs could be on patrol without local resupply.
Aside from implementing a sea denial strategy, he adds that China’s SSKs could perform intelligence, surveillance and reconnaissance (ISR) tasks and covertly insert special operations forces (SOF) before an invasion of Taiwan.
While the US has not built any SSKs since the late 1950s Barbel-class and decommissioned its last SSK in October 1990 in favor of an all-nuclear submarine fleet, there are arguments for and against returning SSKs into US service.
In a June 2018 US Naval Institute (USNI) article, Michael Walker and Austin Krusz argue that despite nuclear submarines’ technological superiority, the US Navy should augment its fleet with conventional submarines due to strategic and fiscal challenges.
Walker and Krusz say that while nuclear submarines offer unmatched endurance and stealth, their high costs and the industrial strain of producing them make a purely nuclear fleet unsustainable.
They mention that SSKs, particularly those with AIP, have become stealthier and more capable, offering a cost-effective alternative. They add that SSKs are especially useful in littoral combat, where their quiet operation and advancements in battery technology allow them to excel.
Additionally, Walker and Krusz mention that SSKs can be produced faster and in more significant numbers, enabling the US to keep pace with the submarine expansions of near-peer competitors like China and Russia.
They suggest a mixed fleet of nuclear and conventional submarines would provide the US Navy with a broader range of capabilities, increased numbers and fiscal sustainability.
In a 2018 article for The National Interest (TNI), James Holtz suggests that SSKs could form the core of an allied fleet with the Japan Maritime Self-Defense Force (JMSDF), reinforcing the US commitment to defending Japan.
Holmes says SSKs are well-suited for the strategic environment, particularly for bottling up Chinese or Russian shipping within the First Island Chain. He argues that despite the advantages of nuclear submarines, SSKs need only to be good enough for the job and affordable enough to buy in bulk.
Holmes emphasizes the need for the US Navy to regenerate its combat power swiftly during wartime, suggesting that mass-producing new submarines would be more feasible with conventional propulsion.
However, despite these arguments in favor of the US again building SSKs, Sebastien Roblin argues in a May 2021 TNI article that SSKs may not fit the US Navy’s global force projection posture, as it operates in the Atlantic, Pacific and Indian Oceans simultaneously.
Roblin notes that navies operating SSKs typically operate within coastal waters, with nearby ports for resupply offsetting the endurance disadvantage of SSKs versus SSNs.