NANJING -- China's new self-developed pile-driving vessel, the world's largest of its kind, has been delivered in the eastern province of Jiangsu. This marks a milestone in the country's marine engineering equipment manufacturing industry.

The record-breaking vessel "Erhang Changqing" features the world's highest derrick at the stern, with the largest piling capacity and strongest resistance to wind and waves, its developer the Second Harbor Engineering Co, Ltd under China Communications Construction Co, Ltd told Xinhua on Monday.

The vessel, built by the Shanghai Zhenhua Heavy Industries Co Ltd, measures 130.5 meters in length, 40.8 meters in width, and 8.4 meters in depth. It is equipped with a 150-meter-high derrick, capable of handling massive pile foundations weighing up to 700 tonnes with a diameter of seven meters.

The former record holder, "Yihang Jinzhuang," also built by the ZPMC, was delivered to CCCC First Harbor Engineering Co Ltd in 2022 with a slightly shorter derrick, 142 meters.

China leads the production of large offshore wind turbines worldwide, making these giant vessels essential for foundation and turbine installations.

In the construction of large bridges and offshore wind farms, multiple steel pipes must be driven into the seabed to form a pile foundation, a task performed by pile-driving vessels.

A pile-driving vessel consists of three main components — the hull, derrick and oil cylinder. The hull serves as the platform, the derrick provides support, and the cylinder acts as the vessel's "heart" to power the moves of the pile frame.

A technological breakthrough made by the CCCC Second Harbor Engineering Co, Ltd is the critical component of an oil cylinder. The one on the new vessel is fully self-developed and weighs 385 tonnes, with a nearly two-meter diameter and a world record-breaking length of 28 meters.

The oil cylinder is the heaviest and tallest in the world, standing as tall as a 10-story building.

Historically, the manufacturing of large oil cylinders in China faces challenges as their components, such as sealing rings, bearing lubrication pads and corrosion-resistant materials, are mainly imported with complicated procurement and high costs, said Yang Xiuli, deputy chief engineer of the CCCC Second Harbor Engineering Co Ltd.

In collaboration with six leading related domestic enterprises and four universities including the prestigious Tsinghua University and Tongji University, "we have successively developed domestic sealing rings, bearing lubrication pads, and corrosion-resistant materials, achieving the goal of localizing super-large and super-long oil cylinders," said Yang.

In addition, the vessel's advanced position system ensures incredible precision, placing piles within just a few centimeters of their designated location on the seabed.

The "Erhang Changqing" is designed to be more environmentally friendly and intelligent than traditional piling vessels.

It utilizes supercapacitors and energy storage batteries to smooth power fluctuations in the grid, paired with a high-efficiency permanent magnet motor for hoisting, resulting in lower fuel consumption and significantly reduced carbon emissions.

Before piling operations, the computer automatically calculates the positioning precision of the piles, while during the piling operation, it will conduct real-time safety monitoring, automatically detect operational processes and generate construction reports, said Yang.