Skirting The Shores

Chinese sources insist the ship is meant solely for civilian research. However, satellite imagery and other open-source information show that the lines separating the Zhu Hai Yun and the People’s Liberation Army (PLA) are exceedingly blurred.

▲ On October 30, 2023, the Zhu Hai Yun set off from its home port in southern China toward Dalian in the north.

▲ In Dalian, the ship docked at a pier operated by the Dalian Institute of Measurement and Control Technology. One of the institute’s primary roles is studying ship vibration and acoustics for the Chinese navy.

▲ Instead of transiting back through the Taiwan Strait, the Zhu Hai Yun took a highly unusual route home.

▲ In the waters off Taiwan’s northern coast, it slowed to a crawl, indicating it likely conducted a research operation.

▲ It then sailed east of the island, an uncharacteristic path for a Chinese civilian research ship. Passing along Taiwan’s coast, the Zhu Hai Yun closely hugged (and appeared to briefly cross into) the island’s contiguous zone, just 24 nautical miles from the shore.

▲ Testing the island’s maritime boundaries while staying within the bounds of international law aligns with Beijing’s increasing use of gray zone tactics to diminish Taiwan’s strategic space.

The Zhu Hai Yun is just one of dozens of Chinese research vessels that scour the world’s oceans collecting data on the marine environment. That data is critical to civilian scientific and commercial research but can also support military intelligence.

Yet the capabilities of the Zhu Hai Yun stand out even among the most advanced ships in China’s research fleet. It is designed to serve as a “mothership” for over 50 unmanned air, surface, and undersea vehicles that can be deployed from its deck while underway.

With the Zhu Hai Yun as the hub, these smaller platforms can simultaneously survey a three-dimensional area spanning 160 kilometers across, 4,000 meters above, and 1,500 meters below the ocean’s surface.

According to Yunzhou Tech, a major unmanned surface vehicle (USV) manufacturer that helped design the Zhu Hai Yun, such autonomous systems can operate together in an “unmanned ship swarm” (无人船艇集群), acting as a force multiplier for survey operations.

▲ Unmanned Aerial Vehicles (UAVs): The Zhu Hai Yun is reported to carry rotary-wing (helicopter-style) UAVs, which can take off directly from two small helipads on the vessel’s deck. The ship may also operate some fixed-wing drones. UAVs can carry out several tasks including offshore inspection and surveillance patrols, as well as supporting resupply and search and rescue missions. They can be equipped with a wide range of advanced sensors, electronic receivers and transmitters, and other instrumentation used to monitor the maritime and air environment. Unmanned Surface Vehicles (USVs): The Zhu Hai Yun is known to carry small USVs, such as the L25C manufactured by Yunzhou Tech. These can be equipped with advanced underwater sensing technologies such as side-scan sonar, multibeam echo-sounders, and magnetic anomaly detection devices (among others), which can support undersea target detection. They also carry powerful towing equipment that can be used to transport large equipment or damaged vessels. Unmanned Underwater Vehicles (UUVs): UUVs can operate below the surface for extended periods, collecting information on undersea conditions in high-risk environments without detection. These assets can include autonomous undersea gliders, which range freely, and stationary “sonobuoys,” which listen for activity around a target area. Some UUVs can operate together to provide real-time situational awareness and detect undersea threats like mines or submarines.

While these technologies can support civilian scientific research, they also have dual-use applications. The USVs and undersea gliders carried on board the Zhu Hai Yun are equipped with advanced instrumentation such as side-scan sonar, which Chinese naval researchers have identified as useful for detecting undersea targets like mines and submarines. Other systems, like aerial drones, can be used to surveil or monitor target areas from the skies.

The vessel also offers a platform for China to live test networked drone swarm operations, an emerging focus area for military planners in both China and the United States. These tactics, which involve overwhelming enemy defenses with waves of low-cost unmanned vehicles, have already reshaped modern warfare in Ukraine. They are also likely to play a major role in a potential conflict over Taiwan.

▲ China boasts the world’s largest fleet of civilian research vessels. While they serve scientific and commercial purposes, they also further Beijing’s strategic goals. Read the full Hidden Reach report to learn more.

Setting it further apart, the vessel’s navigation and control systems are reportedly supported by advanced artificial intelligence software, enabling it to operate autonomously for extended periods without human intervention.

Autonomous navigation for large surface vessels remains a nascent technology, and few ships of the Zhu Hai Yun’s size and range can operate without human guidance. Within the U.S. Navy, the new Expeditionary Fast Transport vessel (EPF 13) is the largest vessel to boast autonomous capabilities. At 103 meters, it is only 14 meters longer than the Zhu Hai Yun.

Satellite imagery and publicly available evidence reveal close ties between the Zhu Hai Yun and the PLA. Construction on the vessel began in 2021 at the Huangpu Shipyard in Guangzhou, one of China’s most prolific naval shipyards.

▲ Imagery from July 24, 2022, shows the Zhu Hai Yun moored side by side with a Type 056A corvette, a modern PLA Navy warship designed for anti-submarine warfare. At least four other warships, in addition to two Type 056 corvettes likely transferred from the PLA Navy to the China Coast Guard, can also be seen nearby.

▲ More recent imagery from January 2023, taken just days before the vessel was delivered to its owner, shows it docked on its own in the same location. Under construction nearby are two Type 054A guided-missile frigates, with another unidentified hull protruding from the adjacent construction hall.

These close physical ties are indicative of the blurred lines between civilian and military shipbuilding in China.

Records indicate that the Zhu Hai Yun was built by the 704th Research Institute, a subsidiary of the massive state-owned defense contractor China State Shipbuilding Corporation. In 2020, the U.S. Commerce Department placed the 704th Research Institute on its Entity List for illegally acquiring U.S.-origin equipment to support the PLA.

The Zhu Hai Yun’s military connections extend beyond the shipyard. Its primary operator is the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), a lab owned by the Zhuhai municipal government and run by Sun Yat-sen University (SYSU).

SYSU is closely linked to the PLA. In 2015, the U.S. government blacklisted an entity within SYSU over its role in hosting the National University of Defense Technology’s Tianhe-2 supercomputer, which supports China’s nuclear weapons program. The SYSU Southern Marine Lab openly promotes both the Zhu Hai Yun and the Tianhe-2 supercomputer as key platforms for its work.

China’s own government has hinted at the vessel’s ties with the defense sector. The powerful State Administration of Science, Technology, and Industry for National Defence (SASTIND) lists updates about the Zhu Hai Yun under the “military science and technology” (军工科技) section of its website.

The evident linkages between the Zhu Hai Yun and China’s military ecosystem raise questions about its November 2023 voyage around Taiwan. The operation’s true purpose remains unknown, but its unique and carefully calculated route suggests it went beyond a standard research mission.

While China’s scientific research vessels frequently operate close to Taiwan (including within its claimed exclusive economic zone), most focus on the area southwest of the island near the disputed Pratas (Dongsha) Island. Activities along Taiwan’s eastern coast are historically rare but may be increasing as China gradually ramps up pressure on the island.

Data accessed from the Windward intelligence platform reveals that, besides the Zhu Hai Yun, only two other Chinese research vessels since 2015 have operated along Taiwan’s east coast in a manner that was not suggestive of either direct transit or surveying the seabed for deposits of natural resources. Just one of those vessels, operating in 2021, circled Taiwan in a route similar to the Zhu Hai Yun’s but did not venture nearly as close to the island.

The Zhu Hai Yun’s close approach to Taiwan’s 24-nautical mile (nm) contiguous zone is significant. In recent years, PLA planes and warships have increasingly pushed closer to the island’s contiguous zone to erode Taipei’s claims of sovereignty over its surrounding waters and airspace. During large-scale military exercises around Taiwan in April 2023, several PLA vessels intentionally intruded into Taiwan’s contiguous zone in a rare and provocative maneuver.

Taiwan’s military commanders have made clear that they will “strike back” against any PLA “entities” that enter Taiwan’s 12 nm territorial waters, but the larger contiguous zone is a murkier gray area.

Navigating along the border of Taiwan’s contiguous zone could also have allowed the Zhu Hai Yun to collect information about the location and activities of Taiwan’s military assets. Several of Taiwan’s major military facilities, including key air bases in Hualien and Taitung, are nestled against the island’s mountainous eastern coast.

The Zhu Hai Yun is just the latest of a set of modern capabilities that Beijing is rapidly testing and fielding that could give China new options for pursuing its military, political, and strategic objectives. While the vessel is not designed to fight with the PLA, it can carry out dual-use missions in key strategic regions of the seas without placing Beijing in hot water.

Matthew P. Funaiole is vice president of iDeas Lab, Andreas C. Dracopoulos Chair in Innovation and senior fellow of China Power Project at the Center for Strategic and International Studies (CSIS). He specializes in using data-driven research to unpack complex policy issues, specifically those related to Chinese foreign and security policy, cross-Strait relations, and maritime trade.

Aidan Powers-Riggs is a research associate for China analysis with the iDeas Lab at CSIS, where he primarily supports the Hidden Reach special initiative.

Brian Hart is a fellow with the China Power Project at CSIS. He also helps to lead Hidden Reach, a CSIS special initiative that shines light on underappreciated sources of China’s influence through open-source data and satellite imagery. Brian’s research focuses primarily on Chinese foreign and security policy, Chinese military modernization, U.S.-China relations, and Taiwan security issues.