Research by the Dutch Safety Board has revealed that the shipping routes above the Wadden Islands during periods of northwestern storm form a risk for large, wide containerships.
The board concludes that due to the value of the Wadden area, it is undesirable that these containerships choose the southern shipping route past the Wadden coast during a northwestern storm.
MSC Zoe
On the night (local time) of January 1, 2019, the Panamanian-flagged containership MSC Zoe with more than 8,000 containers on board was travelling from Sines in Portugal to Bremerhaven in Germany. North of the Dutch Wadden Islands, the vessel found itself in severe weather, and it subsequently lost 342 containers carrying an estimated three million kilograms of cargo into the waters of the North Sea.
The cargo comprised a wide range of items and packaging materials that ultimately washed ashore on the coastline of the Wadden Islands (pictured).
This occurrence caused the board to initiate two investigations: a combined international investigation with Panama and Germany into the course of events of the accident and an investigation by the board itself into the risks on the shipping routes north of the Wadden area.
The latter investigation has revealed that MSC Zoe lost cargo at six locations. The extreme forces acting on the ship, the containers, and the lashing systems as a result of specific conditions on this shipping route were found to be the primary cause of the loss of containers.
Shipping route
Above the Wadden Islands there are two internationally designated shipping routes, a northern and a southern route. The investigation by the Dutch Safety Board has revealed that a combination of a number of phenomena means that on both the southern and northern shipping routes, there is a risk of loss of containers.
In storm-force northwesterly wind, vessels are confronted with high athwartships waves. As a consequence, large, wide containerships make extreme rolling movements.
On the relatively shallow southern shipping route, there is also a risk of grounding due to the combination of vertical and horizontal ship movements. Moreover, waves can slam against the ship, and seawater travelling at high speed along the side of the ship can be forced upwards against the containers.
These phenomena, individually and in combination, cause extreme forces to act on the ship, the containers, and the lashing systems used to retain the containers. As a consequence, containers can break free and be washed overboard.