Experiment aided development of a hybrid mooring and foundation concept for marine energy applications

In this work, the authors present a hybrid gravity-embedment mooring and anchoring solution for the safe and cost-effective station keeping of offshore renewable devices in soft seabed conditions. This is constituted by a series of clump weights of variable mass and size, interconnected through sections of synthetic material. The present study aims at investigating the holding capability of a 1:15 scale single mooring leg in controlled conditions. Tests are conducted in a current flume equipped with a sediment pit, and loads measured by means of a purpose-built frame with pulley and winch. A series of trials testing different configurations of the mooring line is used in order to optimize the design parameters and derive suggestions for future improvements. The paper presents and discusses the failure mechanisms and the failure loads which indicate the holding capability of the proposed design. The study will be of interest to researchers and practitioners considering hybrid mooring configurations.