China tests deep-sea electro-hydrostatic actuator that can cut undersea cables at a depth of 3,500 meters — state hails successful trial and hints at deployment readiness

undersea cable cross section
(Image credit: Getty Images)

China has reportedly conducted a successful test of a 'deep-sea electro-hydrostatic actuator' that can be used to cut through undersea cables up to a depth of 3,500 meters. SCMP reports the device was launched from a research vessel last weekend, and that the state hailed a successful test and the bridging of the gap between development and application, hinting at its readiness for deployment.

According to the report, the 'Haiyang Dizhi 2' completed the first deep-sea mission of the year on April 11. The electro-hydrostatic actuator (EHA), uses hydraulics, an electric motor, and a control unit combined into a single device, jettisoning the requirement for lengthy and cumbersome external oil piping. The device was reportedly further strengthened against deep-sea pressure and corrosion, enabling "precise mechanical tasks" at very low depths. A September report cited by the article notes that this technology has previously been touted "for cutting subsea cables and operating deep-sea grabs."

The project isn't purely destructive in nature, with obvious applications in the repair and building of underwater oil and gas pipelines. However, given the global context and the timing, the implications for military and nefarious use are obvious. Several projects from China's undersea initiative have reportedly drastically improved the effectiveness of such tasks. A 2022 offshore pipeline repair took crews five hours "just to make a single cut" on an 18-inch section of damaged pipe. Just one year later, homegrown vessels operated remotely could cut pipes up to 38 inches in diameter at a depth of 2,000 feet, including one repair where an eight-inch pipe was cut through in just 20 minutes. The latest testing extends these capabilities to at least 3,500 meters, almost 11,500 feet.

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The news comes at a time when undersea infrastructure is coming into sharp focus as a new flashpoint in geopolitical machinations. These cables carry data along the sea floor, connecting global economies and nations via an extensive array of fiber-optic cables. Indeed, in recent years, undersea cables have been the center of disputes, with Russia one of the primary antagonists thought to be monitoring networks and loitering over transatlantic data cables. Earlier this month, it was revealed that the UK navy had tracked three Russian submarines near vital undersea infrastructure. Multiple undersea cables were cut in the Red Sea last year, and a Russian shadow fleet tanker was reported to have dragged its anchor 56 miles along the sea floor in a bid to sever cables in the Baltic Sea.

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Stephen Warwick
News Editor

Stephen is Tom's Hardware's News Editor with almost a decade of industry experience covering technology, having worked at TechRadar, iMore, and even Apple over the years. He has covered the world of consumer tech from nearly every angle, including supply chain rumors, patents, and litigation, and more. When he's not at work, he loves reading about history and playing video games.

  • Scott_Tx
    You dont need a fancy cutter to destroy cables, just drag an anchor like russia does.
    Reply
  • Spuwho
    The US DoD has been installing miles of fiber between the various islands in the Pacific in the Marianas to support its new defense grid. So this announcement is not surprising.

    As for dragging an anchor, the Baltic is much more shallow and regular than the Pacific, so dropping an anchor 3500 meters for a dragging op, may not be feasible, especially since their are crevasses and massives throughout that region.
    Reply
  • derekullo
    Spuwho said:
    The US DoD has been installing miles of fiber between the various islands in the Pacific in the Marianas to support its new defense grid. So this announcement is not surprising.

    As for dragging an anchor, the Baltic is much more shallow and regular than the Pacific, so dropping an anchor 3500 meters for a dragging op, may not be feasible, especially since their are crevasses and massives throughout that region.
    Not to give them ideas, but there are literal maps showing where the cables are ... presumably so you don't accidentally hit them.
    Reply
  • DingusDog
    Scott_Tx said:
    You dont need a fancy cutter to destroy cables, just drag an anchor like russia does.
    Last I checked ships can't drag their anchors at 3,500 feet.
    Reply
  • TechieTwo
    One nuke and any ship is history. :astonished:
    Reply
  • Ktbpylon
    Best China government says best China invention works flawlessly and is the best thing ever.

    Please. Stop. Believing. What. China. Says.
    Reply
  • JamesJones44
    Ktbpylon said:
    Best China government says best China invention works flawlessly and is the best thing ever.

    Please. Stop. Believing. What. China. Says.
    I think I saw they have already developed a way to put laser beams on sharks!
    Reply
  • vinay2070
    Ktbpylon said:
    Best China government says best China invention works flawlessly and is the best thing ever.

    Please. Stop. Believing. What. China. Says.
    The China we had 15 years ago and the China we have now are 2 different beasts. They might be slow in chip production department, but look, they have the best smartphones, fastest cars, best vacuum cleaners, fastest rampup on anything you want to manufacture at the cheapeast of the prices, Car battery replacement network, fastest infrastructure expansion, trying to grow forests in deserts and the list goes on.
    They are moving at a pace that no other country is moving.

    Corruption, low quality manufacturing etc exists in all countries where budget needs to be cut.
    Reply
  • shady28
    vinay2070 said:
    The China we had 15 years ago and the China we have now are 2 different beasts. They might be slow in chip production department, but look, they have the best smartphones, fastest cars, best vacuum cleaners, fastest rampup on anything you want to manufacture at the cheapeast of the prices, Car battery replacement network, fastest infrastructure expansion, trying to grow forests in deserts and the list goes on.
    They are moving at a pace that no other country is moving.

    Corruption, low quality manufacturing etc exists in all countries where budget needs to be cut.

    I'd just point out...

    A few weeks the US used quantum magnetometry to track the location of a lost pilot based on the electromagnetic signature of his heartbeat.

    https://thediplomaticinsight.com/quantum-magnetometry-ai-modern-warfare/
    This was right after flying through Chinese made SAMs that were supposed to be able to see stealth planes.

    https://www.india.com/news/world/chinese-air-defence-systems-fail-miserably-to-defend-iran-how-will-beijing-salvage-its-reputation-usa-israel-china-tehran-shanghai-cooperation-organization-sco-russia-india-brics-8325871/
    And shortly after that, 52 Chinese anti shipping missiles - well they didn't :

    https://www.globaldefensecorp.com/2026/03/18/the-failure-of-the-chinese-cm-302-anti-ship-missile-in-iran-is-a-significant-setback-for-the-chinese-navy/
    And before that in Venezuela, a huge anti-stealth Chinese radar system...

    https://www.eurasiantimes.com/chinas-anti-stealth-jy-27-radar-flops-in-venezuela/

    While China may be moving along, they have a lot farther to go than their propaganda has led people to believe over the past decade or so.

    And this kind of deception has been repeated for years now, wrt their chip making capabilities.
    Reply
  • Pierce2623
    vinay2070 said:
    The China we had 15 years ago and the China we have now are 2 different beasts. They might be slow in chip production department, but look, they have the best smartphones, fastest cars, best vacuum cleaners, fastest rampup on anything you want to manufacture at the cheapeast of the prices, Car battery replacement network, fastest infrastructure expansion, trying to grow forests in deserts and the list goes on.
    They are moving at a pace that no other country is moving.

    Corruption, low quality manufacturing etc exists in all countries where budget needs to be cut.
    Best smartphones? Yeah….no.
    Reply