The Blubber

China Develops Deep-Sea Cable Cutting Tool with Dual-Use Potential

The China Ship Scientific Research Centre (CSSRC) and its State Key Laboratory of Deep-sea Manned Vehicles have developed an advanced deep-sea cable cutting tool capable of severing armored subsea communication cables. These cables—constructed from steel, rubber, and polymer—carry approximately 95% of global data transmissions.

Technical Capabilities

The new tool can cut underwater cables at depths of up to 4,000 meters (13,123 feet)—twice the depth of current subsea communication infrastructure. Designed for integration with China’s crewed and uncrewed submersibles, including the Fendouzhe (Striver) and Haidou series, the device represents a technological advancement in deep-sea operations.

Security and Geopolitical Concerns

Originally developed for civilian applications such as salvage operations and seabed mining, the tool’s dual-use potential has raised concerns about global security and communication stability. The South China Morning Post reports that its use near strategic chokepoints—such as Guam, a key location in the U.S. military’s second island chain defense strategy—could significantly disrupt international communications, potentially leading to a geopolitical crisis.

Engineering and Design Innovations

A team led by engineer Hu Haolong detailed the tool’s capabilities in a peer-reviewed paper published in the Chinese-language journal Mechanical Engineer on February 24. The tool overcomes several technical challenges associated with deep-sea conditions:

• Pressure Resistance: The device's titanium alloy shell and oil-compensated seals enable operation under extreme pressures exceeding 400 atmospheres, preventing implosion.
• Cutting Mechanism: Conventional blades struggle against steel-reinforced cables, so the team developed a 150mm (six-inch) diamond-coated grinding wheel rotating at 1,600 rpm. This high-speed mechanism shatters steel fibers while minimizing marine sediment disturbance.
• Power Efficiency: Designed for submersibles with limited energy resources, the device features a one-kilowatt motor and an 8:1 gear reducer, balancing torque (six Newton-meters) with operational efficiency. However, prolonged use may cause overheating.
• Precision in Low Visibility: The tool is operated by robotic arms and incorporates advanced positioning technology to ensure precise alignment in near-zero visibility conditions.

China’s Expanding Undersea Capabilities

The development of this tool aligns with China’s broader expansion in undersea infrastructure. Beijing now operates the largest fleet of crewed and uncrewed submersibles in the world, with the ability to access all ocean regions.

Because the cable-cutting tool can be deployed from stealthy unmanned platforms, it raises strategic concerns. This has led to discussions within military research communities, particularly after the destruction of Russia’s seabed natural gas pipeline by unidentified actors during the Ukraine conflict.

Despite these concerns, Chinese scientists maintain that the tool is intended for marine resource development. In ground trials, it successfully cut through 60mm-thick cables, supporting the increasing global shift toward deep-sea resource exploitation.