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

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.