A compact, deep-sea, cable-cutting device, capable of severing the world’s most fortified underwater communication or power lines, has been unveiled by China – and it could shake up global maritime power dynamics.
The revelation marks the first time any country has officially disclosed that it has such an asset, capable of disrupting critical undersea networks.
The tool, which is able to cut lines at depths of up to 4,000 metres (13,123 feet) – twice the maximum operational range of existing subsea communication infrastructure – has been designed specifically for integration with China’s advanced crewed and uncrewed submersibles like the Fendouzhe, or Striver, and the Haidou series.
Developed by the China Ship Scientific Research Centre (CSSRC) and its affiliated State Key Laboratory of Deep-sea Manned Vehicles, the device targets armoured cables – layered with steel, rubber and polymer sheaths – that underpin 95 per cent of global data transmission.
While it was created as a tool for civilian salvage and seabed mining, the dual-use potential of the tool could send alarm bells ringing for other nations.
For example, cutting cables near strategic chokepoints such as Guam, which is a linchpin of the US military’s second island chain, a defence strategy used to contain China, the tool could essentially destabilise global communications during a geopolitical crisis.
The cutting tool’s design has overcome several formidable technical challenges arising from the deep, according to the team led by engineer Hu Haolong in a peer-reviewed paper published in Chinese-language journal Mechanical Engineer on February 24.
At 4,000 metres, water pressure exceeds 400 atmospheres. The device’s titanium alloy shell and oil-compensated seals prevent implosion, even under sustained use.
Traditional blades also falter against steel-reinforced cables. The solution, according to Hu and his colleagues, was a 150mm (six-inch) diamond-coated grinding wheel spinning at 1,600rpm – enough force to shatter steel while minimising marine sediment disturbance.
Mounted on submersibles with constrained power budgets, the tool’s one kilowatt motor and 8:1 gear reducer balance torque (six Newton-metres) with efficiency, though prolonged cuts risk overheating.
Operated by robotic arms in near-zero visibility, the tool is also designed to work with advanced positioning technology to avoid misalignment.
The debut of the device comes as China’s foothold in undersea infrastructure is expanding.
Beijing now operates the world’s largest fleet of crewed and uncrewed submersibles, capable of reaching any part of the world’s oceans.
Construction of a 2,000-metre-deep “space station” on the floor of the South China Sea started last month to support at least six people staying for a month.
Meanwhile, America’s ageing deep-sea fleet is struggling to keep pace. And Japan’s sole crewed submersible, Shinkai 6500, faces retirement in a few years without a successor.
Guam remains a cornerstone of the US Indo-Pacific strategy, hosting more than a dozen fibre-optic cables that serve both military and civilian clients, including Google.
China’s tool, operable from stealthy unmanned platforms, could exploit such bottlenecks without surfacing – a scenario that has drawn increasing discussions in military research communities since Russia’s seabed natural gas pipeline was blown up by unknown players during the war with Ukraine.
But Hu’s team insists that the tool, which has undergone successful trials slicing 60mm-thick cables in ground experiments, aids “marine resource development”.
“Nations are now compelled to redirect their resource exploitation focus towards the seas,” they wrote.
“The 21st century is the century of the oceans. Enhancing marine resource development capabilities, advancing the blue economy and building China into a maritime powerhouse constitute critical components of realising the Chinese dream.”
