Bulk ship routing and scheduling: solving practical problems may provide better results

摘要

Scheduling shipments of bulk cargoes when multiple cargoes may be on board a vessel simultaneously is an especially complicated task. Most research on such bulk ship routing and scheduling problems has focused on solving a simplified version of the real problem, which we denote as the basic problem. However, practical problems often pose additional complexities and opportunities that are not considered in the basic problem. We present the basic bulk ship routing and scheduling problem and three practical extensions to it: (1) flexible cargo quantities, (2) split cargoes, and (3) sailing speed optimization. Consolidating results from various sources we show that, although the problems become harder to solve when introducing these practical extensions, significantly better solutions can be obtained by using advanced heuristics. Each of these extensions may increase profit contribution by 5-25% compared to solutions of the basic problem. These methods have been incorporated into a commercial software product used by several shipping companies. Thus, such fleet operators have the opportunity to significantly improve their financial results.