Optimal reefer slot conversion for container freight transportation

ABSTRACT

Given a fleet of container ships of varying capacity, a cost-efficient approach for improving fleet utilization and reducing the number of delayed containers is to optimize the sequence of container ships in a given string, a problem which belongs to the large ship-deployment class. A string sequence with ‘uniformly’ distributed ship capacity is more likely to accommodate a random container shipment demand. The number of one’s total ship slots acts as a gauge of the capacity of the container ships. Meanwhile, there are two types of ship slots: dry slots and reefer slots. A dry slot only accommodates a dry container, while a reefer slot can accommodate either a dry or a reefer container. The numbers of dry and reefer slots for ships in a string are different. Therefore, in this study, we propose a model that considers both dry and reefer slots and use it to elucidate the optimal ship-deployment sequence. The objective is to minimize the delay of dry and reefer containers when the demand is uncertain. Furthermore, based on the optimal sequence deduced, the study also investigates the need to convert some dry slots to reefer slots for the container ships.

KEYWORDS:

• Ship slots
• fleet deployment planning
• sequence of ships
• strings
• uncertainty

Acknowledgments

This work was supported by the Projects of International Cooperation and Exchange: [Grant Number 51561135003], Key Projects: [Grant Number 51638004], and Youth Program: [Grant Number 71501038] of the National Natural Science Foundation of China.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Projects of International Cooperation and Exchange: [Grant Number 51561135003], Key Projects: [Grant Number 51638004], and Youth Program: [Grant Number 71501038] of the National Natural Science Foundation of China.