On February 23, China's independently developed fourth-generation offshore engineering installation vessels, the "Zhigao" and the "Zhiyuan," were successfully completed in Nantong, Jiangsu. The main task of these two vessels is to transport wind turbines—commonly known as "big windmills"—to deep and distant seas and carry out installation and other construction operations. The completion of these two engineering installation vessels is of great significance for promoting the large-scale development of deep-sea wind power and accelerating the green and low-carbon transformation of energy.

According to the reporter, next to China's fourth-generation offshore engineering installation vessel "Zhiyuan" is the offshore engineering crane vessel "Zhigao," completed at the same time. The two vessels were designed together and work in coordination, forming China's optimal combination for offshore engineering installation. They can operate in waters 100 kilometers offshore, providing strong support for China's offshore wind power to advance into deep and distant seas.

This offshore wind power "Gemini" installation vessel is China's fourth-generation wind power offshore engineering equipment and also the world's latest-generation wind power installation vessel. Compared with third-generation offshore engineering equipment, it has achieved a qualitative improvement in technology and performance. This offshore engineering "Gemini" combination is one of the wind power installation vessel combinations with the strongest wind and wave resistance, the best comprehensive installation capability, and the highest operating efficiency and intelligent level in China.

Chief Engineer Zhang Weifeng introduced that the two vessels require only two to three days to complete the installation of one offshore wind turbine, 30% faster than third-generation wind power installation vessels, and can withstand Level 16 gales and 12-meter waves. They will become core equipment for China to promote the large-scale development of deep-sea wind power.

The "Popeye" and "Deep-Sea Giant" of offshore wind turbine installation

As China's fourth-generation offshore engineering installation vessels, the "Zhigao" and the "Zhiyuan" have outstanding operational capabilities in deep-sea lifting, pile driving, and other areas. What unique designs and advanced technologies do they have? Next, follow the reporter aboard to learn up close about these two major offshore wind power installation tools.

According to the reporter, these two vessels are the best partners for offshore engineering equipment installation, each with its own strengths. The main function of the "Zhigao" is lifting and foundation pile driving; it is like a "Popeye" with immensely powerful "arms." The giant red bucket pile at the stern, together with the 130-meter-long boom on top, forms its main lifting system. The huge anchor-shaped object here is its main hook, like a person's grip, capable of lifting 3,600 tons of cargo, equivalent to lifting 2,500 family cars at once. It can rotate 360 degrees, and compared with the previous generation of offshore engineering installation vessels, its rotation speed has doubled.

Boarding the "Zhiyuan," the reporter found that its biggest difference from the "Zhigao," which floats on the sea surface during operations, is that this vessel has four additional 125-meter "long legs"—the gray frame structures behind the reporter. This enables it to penetrate deep into the seabed and carry out offshore wind turbine installation operations in waters 70 meters deep. The red column-shaped tower is the crane of the Zhiyuan, which can lift cargo to a height of 170 meters, equivalent to a 58-story building. The final installation work of offshore units, especially the installation of the wind turbine nacelle and blades, is completed by it.

So how do the "Zhigao" and "Zhiyuan" work together to complete the installation of one wind turbine? First, the "Zhigao" uses its "big iron arm" to lift the steel pipe pile and insert it into the water, lifts the pile hammer, and drives the steel pipe pile into the seabed to complete foundation pile driving. Then, the "Zhiyuan" uses its "long legs" to firmly penetrate the seabed and raises its hull to provide a stable platform for offshore installation. It lifts the tower onto the foundation and installs the wind turbine nacelle and blades one by one atop the tower, and the wind turbine is thus installed. Working closely together, the two vessels can meet the needs of efficient integrated offshore wind power construction operations in deep and distant seas for units with a single-unit capacity of 25 megawatts.