Extreme behaviour in shallow water explains why large containerships can lose containers above the Dutch Wadden Islands

摘要

On the night of January 1-2, 2019, the ULCS MSC Zoe was sailing eastbound on the southerly route along the Dutch Wadden Islands when she got caught in a north-westerly storm. The ship eventually lost 342 containers during the storm. This led to large-scale pollution of the sea and of the Wadden Islands, which are a UNESCO World Heritage site. Combining simulations and available bathymetric models, Deltares was able to determine the wind, current, water depth and wave conditions along the route. The water depth was estimated to be between 21 and 26 m, considering tidal effects. When the incident happened a north-westerly storm was present over the North Sea, with a wind force up to Beaufort 8 and waves of a significant height of 6.5 m with extreme heights up to 11 m. The wind and wave direction was nearly perpendicular to the route. According to Deltares these storm conditions are not exceptional, occurring once or twice every year in this area.