ABSTRACT
Mooring systems are widely employed by floating offshore structures such as ship-shape vessels and platforms for station keeping purposes. Over the last years the development of the offshore Wave Energy Converters brought a new field of employment of these systems. Unlike the other mentioned floating structures, WECs are classified as Near Shore Devices and are commonly installed in water depths up to around 80 m, but in general between 40 and 60 m. Their location, combined with their functional requirements, makes the mooring problem of these devices to be different and sometimes more complex from that of the other offshore structures. As a consequence the accumulated experience in the design of mooring systems for offshore platforms most of the times cannot be applied directly and new codes and standards have to be developed. The aim of this paper is to propose a semi-analytical static formulation able to solve a three-dimensional partially grounded multiline mooring system, which results could be used as framework for a more robust numerical formulation adapted specifically to the WECs’ systems design requirements. In fact, in spite additional loads, due to vortexes and current drifts, and the moorings’dynamic response were to be considered, most of the times for the purpose of preliminary design a quasi-static analysis is adequate and offers a significant reduction in computational cost.
