Creative Destruction: PRC Undersea Cable Technology

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Map of undersea cables surrounding Taiwan. (Source: screenshot, submarinecablemap.com)

Executive Summary:

  • Taiwan has suffered an annual average of 7–8 undersea cable disruptions over the past three years, most of which it attributes to vessels from the People’s Republic of China (PRC). Undersea cables carry 95 percent of global internet traffic.
  • Recent PRC research and patented technologies includes tools to locate and sever undersea cables. Ostensibly for civilian use, these tools have clear dual-use potential, and could be deployed in military applications in contested waters like the Taiwan Strait.
  • Military universities, “Sevens Sons of National Defense” universities, and companies that are part of the PRC’s defense industrial base are behind much of this research and development.

On January 3, a vessel owned by a company registered in Hong Kong severed an undersea communications cable near Taiwan, disrupting data traffic and heightening concerns about critical infrastructure vulnerabilities (Taiwan Coast Guard Administration, Ocean Affairs Council [CGA], January 6). This is not an isolated incident. According to Taiwan’s National Security Bureau, the island has experienced an average of 7–8 undersea cable disruptions annually over the past three years, most of which it attributes to vessels from the People’s Republic of China (PRC) (Taiwan Public Television Service, January 16).

This latest incident could be another gray zone tactic designed to destabilize without triggering open conflict, as the Ocean Affairs Council, which oversees Taiwan’s Coast Guard Administration, acknowledged (CGA, January 7). This possibility is supported by evidence of PRC advancements in undersea cable technology. Technology patented in the PRC such as tools to cut undersea cables is ostensibly focused on maintenance and repair, but also carries dual-use potential.

PRC Research on Undersea Technology

Evolving Algorithms for Submarine Cable Localization

Cutting-edge research conducted in the PRC in recent years has focused on developing undersea cable technology. This includes work on algorithmically enhanced robotics. A study funded by the National Natural Science Foundation of China and published in May 2024 is titled Submarine Cable Localization Algorithm for Underwater Robots Based on Improved Grey Wolf Optimization Algorithm. It details a robotic tool that uses novel magnetic induction techniques and is powered by an algorithm developed by the researchers to improve the precision and reliability with which cable routes and faults can be detected. [1]

Primarily framed as being designed for routine inspections and repairs, these tools also lend themselves to military applications, including damaging or disrupting cables. Huang Wen-chao (黄文超), the principal author of the research, was affiliated with the Harbin Engineering University (哈尔滨工程大学), one of the Seven Sons of National Defense. [2] He also heads a project on the “Development of a Non-Contact Intelligent High-Precision Positioning System for Submarine Cable Routing and Fault Points,” which is a key project of the Fujian Provincial Department of Science and Technology (College of Electrical Engineering and Automation of Fuzhou University, December 18, 2017). Such dual-use capabilities align with the PRC’s broader strategy of leveraging civilian technologies for potential military advantage in contested regions.

Advanced Sonar Systems for Submarine Cable Break Detection

Additional research published in the last year focuses on using sonar to locate breaks in submarine cables. A study by researchers at the Ocean University of China, combines two kinds of sonar technology to enhance detection capabilities, including by helping to resolve the challenge of locating buried cables. The researchers also highlight the utility of ultra-short baseline positioning systems for repair teams navigating to damaged sites. [3]

These innovations are also designed for civilian applications, in this case maintaining offshore wind farms and energy infrastructure. However, this also does not preclude their use in military applications. The ability to swiftly locate and manipulate submarine cables in contested waters could be leveraged for offensive actions, including sabotaging critical communication networks.

Patented Technologies Have Dual-Use Potential

Over the past decade, a number of patents filed by PRC institutions and companies have focused on precise, rapid, and cost-efficient manipulation of undersea cables. For instance, in 2013, the Institute of Communication Application under the People’s Liberation Army (PLA) Navy (中国人民解放军海军通信应用研究所) filed a patent for a deep-sea optical cable shear and retrieval device (CN102358407B). In other words, a tool for cutting submarine cables (Google Patents, accessed January 10). The provenance of the patent, a military institution, suggests that it was likely designed for covert operations and sabotage.

In 2022, the PLA Naval University of Engineering (中国人民解放军海军工程大学) filed a patent for an optical cable retrieval system (CN115258102A). This system incorporates tools for severing cables and securing both ends of severed cables simultaneously, among other features (Google Patents, accessed January 10). PLA involvement in undersea cable technology raises red flags, as management of such cables typically falls under civilian jurisdiction according to PRC law.

Civilian institutions have also contributed similar tools. In 2020, Lishui University (丽水学院) filed a patent for a cable cutting device that can be towed behind a vessel (CN111203499A), citing the need for a low-cost, efficient solution for severing cables during emergencies (Google Patents, accessed January 10). The patent critiques traditional methods as expensive and operationally complex, framing the innovation as a practical alternative. However, such an “emergency” tool could be deployed with equal applicability in geopolitical crises or non-civilian contexts.

Most recently, in January 2025, the PRC firm Zhuhai Yunzhou Intelligence Technology (珠海云洲智能科技) secured a patent for an undersea cutting device and towed cutting system (CN222242405U). (Baijiahao, January 3). According to its website, the company specializes in maritime engineering, smart water management, and public safety. The mission of the company is to “leverage smart technology to explore, protect, and manage the oceans, and strive to realize the dream of becoming a strong maritime nation driven by technology (用智能科技探索海洋、保护海洋、经略海洋，践行海洋科技强国梦).” According to PRC President Xi Jinping, this is an integral part of the country’s maritime strategy (Yunzhou, accessed January 16; Qstheory, August 31, 2017). At the 15th China International Aviation and Aerospace Exhibition (第十五届中国航展) in November 2024, Yunzhou showcased its unmanned boat formations, known as “Sea Sentinels (海上哨兵),” promoting their utility for maritime patrol and reconnaissance (Yunzhou, accessed January 10).

Conclusion

There is no conclusive evidence to date that the PRC has intentionally targeted and sabotaged undersea cables around Taiwan. However, clear technological advances in undersea cable technology, and numerous cases of cables around Taiwan being cut in recent years, and a dramatic increase in PRC efforts to enforce its territorial claims and engage in gray zone activities constitute strong circumstantial evidence.

It is important to scrutinize whether these developments address practical needs or signal preparation for coercive actions, given the PRC’s pattern of integrating civilian and military technologies. Regardless of intent, the growing disparity in undersea cable capabilities requires international attention. Enhancing cable security, deploying advanced monitoring systems, and establishing global norms to deter misuse are critical steps to ensure these systems remain tools for connection rather than instruments of conflict.

Notes

[1] Huang, W., Wen, J., & Xu, Z, Submarine Cable Localization Algorithm for Underwater Robots Based on Improved Grey Wolf Optimization Algorithm. Control and Decision, May 2024.

[2] The Seven Sons of National Defense are a group of seven universities with close ties to the People’s Liberation Army. Students tend to focus on research that has military applications, and graduates often go on to work in the PRC’s defense industry. The seven institutions are: Beijing University of Aeronautics and Astronautics (北京航空航天大学), Beijing Institute of Technology (北京理工大学), Nanjing University of Aeronautics and Astronautics (南京航空航天大学), Nanjing University of Science and Technology (南京理工大学), Northwestern Polytechnical University (西北工业大学), Harbin Institute of Technology (哈尔滨工业大学), and Harbin Engineering University (哈尔滨工程大学).

[3] Zhao, Y, Research and Application of Submarine Cable Break Point Positioning Technology. China Water Transport, December 2024.