A ship weather-routing tool for route evaluation and selection: influence of the wave spectrum

A tool has been developed to assess safety and efficiency of shipping routes across the Mediterranean Sea. The tool is based on combining the strip-theory programme PDSTRIP with the Wave-watch III operational model run at DICCA, University of Genoa, to assess safety, efficiency and comfort parameters of vessels and assist in route selection and optimisation. In this paper, the focus is on analysing the effect of parametric versus full wave spectra on the response of the vessel and the consequent route selection. The influence of the wave spectrum is demonstrated initially for an example sea-state localised in Eastern Liguria, and subsequently for a route from Genoa, Italy to Tangier, Morocco, with three predetermined route variations. A typical passenger ferry is considered with an operational ship speed of 15 kn, corresponding to a Froude number of 0.22. It is shown that using standard parametric formulations for the wave spectrum versus the full (numerically forecasted) directional spectrum can affect the route evaluation and potentially lead to a different optimum route choice.