Limitations of Helical Screw Anchors for Offshore Structures

Abstract

AbstractHelical anchors have been used since the mid 1800’s to secure vessels and structures offshore. There has recently been renewed interest in this technology for anchoring offshore floating and submerged structures such as large floating wind generators and submerged current or tidal generators. Helical anchors may offer a number of distinct advantages over other types of anchors for these applications. They can be designed with a round or square central shaft and can have a single helical plate or multiple helical plates depending on the design load requirements. They may be removed easily if needed, as in the case of temporary works or decommisioning, they have a low carbon footprint, and installation generally produces low noise and vibration levels. However, screw anchors may also have limitations that need to be clearly recognized in order to make efficient and cost-effective use of the technology. Estimating the required installation torque for different geometries at specific sites may be challenging. Potential limitations of using helical anchors offshore are discussed.KeywordsHelicalAnchorsOffshore