China Deploys Sihang Yongsheng Heavy-Lift Crane Vessel

Naval architecture achieved a significant milestone with the official delivery of the Sihang Yongsheng in Jiangmen, located in China’s Guangdong province. Constructed by Jiangmen Hengtong Shipbuilding—a subsidiary of CCCC Fourth Harbor Engineering—the vessel arrives as the largest full-circle slewing semi-submersible crane vessel in China by lifting power.

Engineering Specifications of the Sihang Yongsheng

The vessel operates as a non-self-propelled semi-submersible platform measuring 110 meters in length and 43.8 meters in breadth. It features a continuous deck spanning a large area, built specifically to transport oversized components. At the stern sits its most defining feature: a full-circle slewing jib crane equipped with a 149-meter boom.

When anchored, the crane can rotate a full 360 degrees while lifting heavy structures up to a maximum height of 172.5 meters, comparable to a building of more than 50 stories. During fixed-position maneuvers, the system lifts up to 2,200 metric tons, translating to approximately equivalent U.S. tons in a single lift. Project chief engineer Huang Chenguang noted that the system was engineered to handle extraordinary structural dimensions in marine environments where wave action, workspace limitations, and strict precision make operations difficult.

Semi-Submersible Deck Operations and Automated Stability

Beyond its heavy lifting capacity, the vessel functions as a heavy transporter. Its unobstructed deck accommodates components weighing up to massive limits. The hull can partially submerge to adopt a semi-submersible configuration, simplifying the loading and offloading of bulky marine equipment.

This dual capability allows a single platform to alternate between heavy transport and offshore installation. To manage the immense weights involved in shifting maritime conditions, the vessel incorporates an intelligent load-adjustment system. This automated technology calculates operational parameters and maintains vessel balance without requiring constant manual intervention.

Industrial Applications and Manufacturing Requirements

Following its delivery, the megacrane vessel is scheduled to participate in maritime bridge construction, port installations, offshore wind farms, marine ranches, and deep-water exploration initiatives. Lin Boqiang, director of the China Center for Energy Economics Research at Xiamen University, pointed out that constructing vessels of this scale demands advanced integrated design, specialized materials, refined manufacturing processes, and a robust industrial chain capable of producing large-scale equipment.