China may be preparing to deploy its massive new unmanned subs in the South China Sea, as recently released satellite photos would seem to indicate. However, China’s intentions for the new subs is still unclear, sparking speculation among analysts on how it may use the platforms in future naval operations.
Naval News reported this month that satellite imagery showed two of China’s extra-large uncrewed underwater vehicles (XLUUV) at Sanya Naval Base on Hainan Island, which geographically juts into the contested South China Sea.
The report notes that the two vehicles have been present at the base since March and April 2021 but have only been spotted now. It also mentions that the two XLUUVs have been seen near an area where China has previously based its midget submarines, indicating trials or testing.
Writing for Naval News, defense analyst H I Sutton notes that the first XLUUV is around 16 meters long and two meters across. It features a streamlined bow and appears to have two side-by-side tail propellers, indicating that the vessel may be related to the HSU-001 Large Displacement Unmanned Underwater Vehicle (LDUUV), which was first unveiled in 2019.
Sutton notes in Covert Shores that the HSU-001 LDUUV is large enough to carry smaller UUVs, sensors and naval mines, and that it appears to be designed primarily for Intelligence, Surveillance, and Reconnaissance (ISR) purposes.
Its twin propellers, meanwhile, suggest that it is optimized for near-surface low-speed cruising instead of deep-diving. It also features vertical and horizontal thrusters fore and aft, launch and recovery lugs on top and what appears to be attachment hardpoints across the sides of its hull.
However, Sutton mentions in Naval News that the first XLUUV is twice the size of the HSU-001 LDUUV and has many features in common with the US Navy’s Boeing Orca XLUUV. In addition, he notes that China has had XLUUVs in the water since 2021 while the US commissioned its first Orca this April, suggesting China’s lead in the technology.
Naval Technology notes that Boeing’s Orca is based on the Echo Voyager prototype, which is 26 meters long, including an added modular payload bay. The Orca can operate for months at sea and may be launched and recovered without the help of support ships.
The Orca’s modular payload bay can carry up to eight tons of dry weight alongside external payloads. It is designed to cruise with an optimal speed of 2-3 kilometers per hour, an 8-kilometer per hour max speed and an operational range of 6,500 nautical miles.
For China’s second XLUUV spotted in the satellite photos, Sutton mentions in Naval News that it is outwardly slimmer in form but longer at around 18 meters. In addition, he notes that China’s second XLUUV is reminiscent of Lockheed Martin’s contender for the US Navy’s Orca program.
Although no details for Lockheed Martin’s Orca contender are available, Sutton mentions in Covert Shores that its torpedo-like design features modularity with an open architecture to allow multiple payload configurations.
Regarding operational use, Sutton says in Naval News that XLUUVs are capable of performing ISR missions. In addition, their larger size translates into longer sea endurance, which enables them to be used for offensive operations such as minelaying, anti-submarine warfare and special operations.
More broadly, China’s introduction of XLUUVs points to the growing dronification of underwater warfare. Asia Times has previously reported on this trend, noting that the South China Sea may be an ideal operating environment for XLUUVs, as its unmapped underwater features and shallows make navigation hazardous for manned naval combatants.
At the same time, the contested sea’s features, shallows and high shipping traffic could allow XLUUVs to remain undetected for long periods by using these environmental factors. They could also be used for bathymetric mapping, finding underwater blind spots where submarines can navigate undetected and hide for prolonged periods.
China’s XLUUVs substantially add to its growing unmanned naval warfare capabilities. This June, Asia Times reported on China’s unmanned AI-powered drone mothership, which is the first of its kind in service. The ship’s domestically-developed custom AI allows it to operate 50 aerial, surface and submersible drones that are capable of forming a network to observe targets.
China is also known to be testing unmanned drone motherships for combat operations. For example, Yunzhou Tech, its most successful autonomous vessel company, is working on an unmanned drone ship that will carry six smaller drones to attack surface ships using swarm tactics.
However, the increasing dronification of underwater warfare comes with significant caveats. An August report from the US Congressional Research Service (CRS) notes the potential for miscalculation and escalation with unmanned vessels, mentioning that they make tempting targets.
Due to the lack of human crews, they are viewed as expendable. Because of this, commanders may feel emboldened to strike at them, lowering the threshold for military action.
The CRS report also notes the lack of norms governing the use of these unmanned systems, and mentions the need for an expanded right-of-way hierarchy and non-interference standards to clarify how manned ships and aircraft should interact with their unmanned counterparts.
The report emphasizes that without human guidance of unmanned systems, the risk of escalation increases, with an incident without any immediate human presence or losses potentially sparking a wider conflict at sea and beyond.