VESSEL REVIEW | Erhang Changqing – Chinese piling vessel built for offshore installation and bridge construction

China Communications Construction Company (CCCC) has taken delivery of a new offshore piling vessel built by local shipyard Shanghai Zhenhua Heavy Industries (ZPMC).

Erhang Changqing (二航长青; "Second Voyage Evergreen") will be operated by CCCC Second Harbour Engineering Bureau. Construction of the vessel was completed in compliance with China Classification Society rules.

The newbuild has an LOA of 130.5 metres (428.1 feet), a beam of 40.8 metres (134 feet), a depth of 8.4 metres (28 feet), and a hybrid diesel-electric propulsion consisting of three generators, two supercapacitors and a lithium iron phosphate battery pack with peak shaving.

The vessel consists of three major components: the hull as the main platform, the pile frame to provide support, and the oil cylinder. The cylinder weighs 385 tonnes and has a diameter of nearly two metres (6.6 feet).

Versatile construction platform

The vessel can raise pile foundations of seven metres (23 feet) in diameter and up to 700 tonnes each to a maximum height of 150 metres (490 feet) with the aid of a 5,000-tonne thrust cylinder. The piling capacity thus makes the vessel ideal for a range of applications including the installation of offshore wind turbine generators and large support pillars for the construction of ports and large bridges.

Key features include a piling positioning system, which can monitor and control the plane and the verticality of the pile in real time and help ensure centimetre-level accuracy during piling even in offshore waters; and a piling operation management system, which gathers data on hydrological parameters to ensure safe and secure piling under a range of sea conditions. The vessel's safety equipment meanwhile includes a fixed firefighting system.

Streamlined manufacture through the use of locally built components

Construction of the large thrust cylinder was made possible through the availability of locally manufactured components, whereas earlier cylinders relied partly on importation. Six local enterprises and four universities collaborated and jointly developed the necessary components such as the sealing rigs, the lubricating pads, and the corrosion-resistant material.

Compared with traditional piling vessels, Erhang Changqing is also more environment-friendly and intelligent in design and use. It adopts DC busbar networking technology linking the main generator with the energy storage system and the permanent magnet motor that is used for lifting. The carbon emissions are also significantly reduced.