China Tests Deep-Sea Cable Cutter Technology

China has successfully tested a deep-sea cable-cutting device capable of operating at depths of 3,500 metres, a development that is drawing attention for both its industrial uses and its potential military implications.

The test took place during a recent mission by the research vessel Haiyang Dizhi 2, which completed a sea trial involving a compact electro-hydrostatic actuator designed to cut through underwater structures such as cables and pipelines. Chinese state media described the trial as bridging the “last mile” between development and real-world application, suggesting the technology could soon be ready for deployment.

The device combines a hydraulic system, electric motor, and control unit into a single compact unit, removing the need for large external piping systems. Engineers designed it to withstand extreme underwater pressure and corrosion, allowing it to operate accurately at depths of up to 3,500 metres.

While China says the technology could support civilian tasks such as repairing oil and gas pipelines, the timing of the test has heightened concerns about its potential use against critical undersea infrastructure. More than 95% of global internet traffic passes through submarine cables, many of which sit within the depth range this device can reach.

Security analysts have increasingly warned about the vulnerability of undersea networks, particularly as geopolitical tensions rise. Recent incidents involving damaged cables in the Baltic Sea and Red Sea have already demonstrated how disruptions to these systems can affect communications, financial markets, and military operations. China’s latest test suggests that reaching and severing deeper cables is no longer a theoretical capability.

The technology also reflects the speed of China’s progress in subsea engineering. Just a few years ago, cutting a damaged underwater pipeline could take several hours. More recent Chinese systems have reduced that process to minutes, while also operating at increasingly greater depths.

The broader concern is not only what the technology can do, but how difficult it could be to detect. Experts say the compact design means it could potentially be mounted on smaller unmanned underwater vehicles or research vessels, making covert operations harder to track.

Author: George Nathan Dulnuan