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Condensation inside marine containers occurs during voyages owing to weather changes. In this study, we define the condensation probability along one of the major routes for container ships between Asia and Europe. First, the inside and outside air conditions were measured on land in Japan, and a correlation analysis was conducted to derive their relationship. Second, onboard measurements were conducted for 20,000 twenty-foot equivalent unit (TEU) ships to determine the variation in outside air conditions. Complicated patterns of weather change were observed with changes in latitude, sea area, and season. Third, condensation probability was estimated based on a multi-regression analysis with land and onboard measured data. The maximum condensation probability in westbound or eastbound voyages in winter was found to be approximately 50%. The condensation probability estimation method established in this study can contribute to the quantification of cargo damage risks for the planning of marine container transportation voyages. [ABSTRACT FROM AUTHOR]

Maritime transportation is becoming increasingly complex owing to the fluctuation of oil prices, the introduction of environmental guidelines, and the onset of climate change. Although optimal routing has been researched for decades, few studies have investigated speed loss in rough waves for ships with blunt shape and low speed. Onboard measurement of a 28,000DWT bulk carrier has been conducted for six years in rough sea voyages in the Southern Hemisphere. It is necessary to validate the wave and wind conditions in order to discuss speed loss in these situations. Here, numerical simulation of speed loss is developed and conducted for each estimated wave condition. The speed losses under different numerical models of added resistance are quantitatively compared in two rough sea voyages. The simulated results of speed loss are in good agreement with the measured results if the estimated wave is accurate and the wave direction is properly defined. The speed loss accuracy is significantly influenced by the wave estimation accuracy or wave direction setting compared to that in the numerical models of added resistance in actual seas. Simulated results provide important information to evaluate the performance of a ship with blunt shape in rough waves. [ABSTRACT FROM AUTHOR]

The analysis of ocean surface waves is essential to ensure safe navigation. Since 2010, different on-board observation data from bulk carriers, including those navigating high-risk shipping regions in the southern hemisphere with strong ocean currents, have been collected for 6 years. High-resolution numerical simulations of ocean waves for four rough sea cases, considering the effect of wave-current interaction on ship navigation, have been performed using the WAVEWATCH III model. The simulations considered the ocean surface wind force from the widely used reanalysis database of the National Centers for Environmental Prediction Final and European Center for Medium-range Weather Forecasts Interim Reanalysis. To provide practical suggestions for safe navigation by avoiding possible high-risk ocean regions and construct a more effective and efficient optimum ship routing system, the model results were validated based on on-board observations, followed by discussions on the responses of ship motion and navigation to sea states at different levels. Finally, early warning criteria, including various operational ocean parameters for ballast and loaded ships sailing in rough seas were identified. • Shipboard measurement data with detailed navigation information has been collected for two different years and ship loading conditions. • Four rough seas have been focused on covering important maritime transportation ocean regions. • Wave simulations have been done with a high resolution to obtain detailed sea states. • Statistical approaches has been used to quantitatively study the ship responses to ocean waves. • Ship responses to ocean states are given, quantitatively showing the relationship among ship navigational parameters with ocean parameters. [ABSTRACT FROM AUTHOR]