Stena Line berth
- Molem Marine Works Ltd.
- Port of Holyhead, UK
- Berth piles
- PBA 815, PBA 306
In 2003 Stena Line Ports Ltd has built a new 315m long berth at the Port of Holyhead to provide facilities for the new ships. It included 6 berthing dolphins 2,4m to 3m diameter drilled and installed in the bedrock.
To support the link span another 23 monopiles 0,8m diameter are drilled and installed. All monopiles are installed from jack-up barges and drilled by DDC. The job was executed with the Wirth PBA815 & PBA306 pile top drill rig using drill bits of 650mm and 3000mm diameter.
The PBA815 & PBA306 are hydraulically driven by a power pack and works with the reversed airlift drilling principal for soil removal. Compressed air is injected in the drill pipe just above the cutting head, creating a differential pressure and differential density between the fluid inside and outside the drill pipe. Solids will therefor pass the suction opening and rise up through the drill pipe.