Characterization of anchor penetration behaviour for Cable burial risk assessment

Offshore wind (OSW) power cable failure currently accounts for 75% of the cost of all insurance claims as-sociated with OSW projects and faults typically take 100+ days to rectify. The most effective method for protecting the cables from anchor damage is to bury them in the seabed, but current guidance on how deep they should be buried is ambiguous. There are a number of variables that influence the penetration depth of anchors, such as the anchor size (considered as the weight in kg), fluke length, fluke angle and the soil type and properties. The fluke length and angle vary depending on anchor size, the type of anchor and the manu-facturer. Current industrial guidance suggests that an anchor’s penetration behaviour can be predicted based upon its fluke length and vessel displacement and the soil type but this does not consider the physical proper-ties of the soil. In this paper the penetration behaviour of a Class F (AC-14) anchor has been investigated in sand soil beds of varying relative densities. The results indicate that the penetration depth of the anchor is density dependent and that the anchor penetrates deeper than may be anticipated in very loose sands.