Secondary Steel Installation Tool – Hollandse Kust Zuid OWF

Seaway 7 is transporting and installing 140 TP-less monopile foundations for the Hollandse Kust Zuid OWF. The secondary steel of the monopile foundation will be attached to the monopile after installation.

To optimize operational time and minimize offshore lifts, TWD came up with an efficient Secondary Steel Installation Tool (SSIT). The SSIT can install a Boat Landing System (BLS) and an Air Tight Platform (ATP) simultaneously, with a 360° rotational freedom for easy alignment of the BLS. The tool has guides to centralize it precisely on the monopile with clamps holding it in position.

TWD also designed a storage tower with seafastenings for 4 BLSs, 4 ATPs and the SSIT.

Project highlights:

• Single lift to install BLS and ATP simultaneously
• Guides on SSIT make it possible to use a floating vessel
• SSIT is self-supported/powered (no cable from vessel needed)
• Storage tower allows for easy load-in and load-out of the secondary steel