According to AIS data, the research vessel Zhong Shan Da Xue sailed through the South China Sea from May to June 2025. However, Sun Yat-sen University declared that the vessel was active in the South China Sea in August 2025, which contradicts the AIS data. The announcement stated that Sun Yat-sen University had conducted sea-trials of Haiqin, a remotely operated vehicle (ROV) capable of operating at depths of up to 6,000 meters, and that Zhong Shan Da Xue had deployed the Haidou-1 autonomous underwater vehicle (AUV) at the same time. This marked the first scientific survey conducted by coordinating two different unmanned vehicles via a single support ship¹⁴.

Surveying the Front Line of a Potential Conflict

Last February, a Chinese research ship named the Da Yang Hao sailed along Taiwan’s east coast, tracing a series of parallel lines over five days.

In the months that followed, five other Chinese research ships, including the Xiang Yang Hong 6, returned to the area, following similar routes. They often moved at slow speeds, typically 8 to 10 miles an hour, ideal for mapping undersea features using sonar and other techniques, a science known as bathymetry.