Estimating the Voyage Duration of Transoceanic LNG Transports

A study was made to estimate the transit time of time-critical cargo (LNG) from Western Australia to the Far East (e.g. Japan) or the southern U.S. west coast. Unexpected delays during transit can result in stiff financial penalties imposed by LNG buyers. Conversely, quicker than expected voyages will underutilize expensive tankers. Since there was no prior experience along the two routes using the proposed new-build vessels, the SafeTrans computer simulation program was used to calculate the voyage duration. SafeTrans is a comprehensive routing simulator that accounts for weather routing, ship dynamics, and weather forecast errors. Basic voyage duration statistics are presented and indicate important differences between a) outgoing and returning voyages, b) the two routes, and c) weather-routed and non-weather-routed scenarios. These differences are examined and reveal that voyage duration estimate is significantly impacted by weather routing, and a comprehensive ship motion model and weather database. Finally, our results demonstrate an application of SafeTrans that goes beyond the original purposes of the program, and suggests it might well be useful for estimating the voyage duration for other types of time-critical cargo.Copyright © 2005 by ASME