Space reservation and remarshalling operations for outbound containers in marine terminals

Outbound containers begin to arrive 7-15 days before the corresponding vessel. To reduce the use of yard space, they are stacked in a temporary storage area in the early stages of arrival, and a permanent storage area is subsequently allocated to all containers to be loaded on a certain vessel. Containers arriving before the allocation are moved to the allocated permanent storage area, which is called "remarshalling". This paper proposes a method to determine the right time to remarshal outbound containers, as well as the amount of space reservation required, considering the handling effort for remarshalling and the efficiency of the loading operation. Mathematical formulations and solution algorithms are developed both for a single vessel and for multiple vessels. A simple procedure is proposed for the problem involving only a single vessel, and a genetic algorithm is developed for the multiple vessel problem. Through numerical experiments, it is found that as the remarshalling cost per container increases, ship operating and total costs tend to increase, too, while remarshalling costs do not show any conclusive trend. We also find that an increase in the available space, relative to space requirements, has a higher impact on the reduction of remarshalling costs than on the reduction of ship operating costs. Our results can support yard managers in container terminals to manage efficiently space reservations and remarshalling operations.