During May and July 2019, SAL Heavy Lift demonstrated its offshore installation capabilities at the Greater Changhua Test Pile project, offshore Taiwan.
On behalf of Per Aarsleff, SAL utilised its DP2 installation vessel Lone for the pile installation and testing work, which formed part of the pre-piling phase of the Greater Changhua Offshore Windfarm project.
SAL was tasked with the installation of six piles (two sets of three), with unit weights of up to 140 tonnes.
This involved installing test foundations around the project site – located 50 km off the coast of Taiwan – in water depths of around 35-40 m to assess the seabed conditions. Six piles measuring up 80 m long were hammered into the seabed using a special pile guide frame.
In order to lift the long piles vertically, a jib extension for one of Lone’s cranes was designed, manufactured, installed and tested. The resulting fly jib extension made Lone's crane hook approximately 70 m tall – a 23 m extension.
The vessel also had to be equipped with temporary living quarters and additional lifeboats. To operate as an offshore installation vessel, with so many people on board, Lone had to change its certification from cargo vessel to special purpose ship (SPS).
After the installation, the second phase of the project began in August 2019. This involved static and dynamic testing on selected piles on the seabed. These tests provided engineers from Ørsted, the project developer, with the necessary data to optimise pile design for the wind farm.
The installed piles were subsequently decommissioned from the seabed, lifted back onto the deck of Lone and transported to shore for recycling.