Nonlinear Hydrodynamic Analysis of Ships Moored in a VLFS Service Basin in the East Mediterranean Sea

Roy Gafter,Nitai Drimer

doi:10.3390/jmse10030382

Abstract

Very large floating structure (VLFS) is an environmentally sensitive technology which creates artificial land at sea. Designated for the open sea, the Delta is a new type of VLFS. Formed, inherently, by the innovative geometry, the sheltered basin is a unique feature of the Delta. Its year-round operability as the gateway of the structure directly affects the Delta’s utilization. This study examines the basin in terms of its operability as a service port. Relying on potential flow theory and applying the boundary element method, we conducted a nonlinear hydrodynamic analysis of a moored vessel at the basin. It consists of a time-domain simulation of a tanker, berthed via nonlinear mooring system along the Delta’s side hull under severe wave conditions typical to the East Mediterranean Sea. The system is evaluated in terms of acceptable motion of the ship and permissible load on the mooring system. The favorable results indicate that the basin enables most cargo handling operations under waves conditions of Hmo=2.5 m, and minimal downtime of less than 6% of the year. In this paper we present the analysis procedure, the evaluation criteria, and the mooring system’s design. The study results and their significance are presented and discussed as well.

Highlights

Overexploitation of the land, enhanced by the constant rise of population density in coastal regions is a major global concern [1–3]
very large floating structure (VLFS) types are traditionally categorized by their hull configurations into the pontoon or the semisubmersible types [8,9]
It is designed to operate at intermediate open sea condition and to withstand severe weather conditions with minimal downtime

Summary

Introduction

Overexploitation of the land, enhanced by the constant rise of population density in coastal regions is a major global concern [1–3]. Offering broad space and high stability, it can be utilized for the accommodation of landbased operations out at sea. It may provide a much-needed relief and enable a more sustainable development in coastal regions. This study focuses on the sheltered basin and examines its operability as a service port and, as an expansion to the mentioned hydrodynamic study, we constructed an analysis procedure so it may be utilized as a design evaluation tool. While the same practice is common to the development of harbors, by means of numerical or physical agitation models, we here applied it to assess an innovative concept of VLFS, to extend the use of the open sea

Methods

Results

Conclusion