Delta-type VLFS–hydrodynamic aspects

A Very Large Floating Structure (VLFS) is a promising concept for the utilisation of the sea. Currently, VLFSs are classified into two broad categories: the pontoon-type, limited to sheltered water, and the semi-submersible type, for open-ocean. We present a new concept, the delta-type, an important feature of which is the formation of a sheltered basin, providing accessibility in most weather conditions. Initiating the development of this concept, we study its hydrodynamic aspects: basin efficiency, motion, comfort and mooring. We present a case study, for which we compare the hydrodynamic aspects for four configurations of equal utilisation areas. The agitation in the basin and the motion are solved linearly for regular and irregular seas. A single-point mooring system is designed and solved in the time-domain, considering the second-order slow-drift motion that is critical to the mooring loads. We obtained promising results that justify the next stage of the study–structural aspects.