Tramp Ship Routing And Scheduling With Random Factors

Tramp shipping is the main transportation mode for dry bulk cargoes which is possible to be affected by some stochastic factors. On one hand, the demands for dry bulk cargoes show an obvious seasonality. Different quantities and flows of such cargo demands in different times and different routes are fluctuant, which is related to whether it is the peak season. On the other hand, technical characteristics of international shipping lines in each period of a year are different. If the rout segment is unavailable (e.g., unseaworthy conditions), ships sailing in it will be easy to be delayed and increase extra costs. Therefore, for bulk shipping companies, it’s important to discuss when and where to make the ship in ballast, since a reasonable scheme can help to increase profit.This paper studies the tramp ship routing and scheduling problem (TPSRP) by taking into account seasonal fluctuation of demand and unseaworthy condition caused by weather factors. A mathematical model is proposed which attempts to maximize the total voyage profit of shipping company in the planning period. Since the problem is an NP-hard problem, a genetic algorithm-based heuristic is developed to solve the problem. The operation data of a Chinese tramp shipping company are used to validate the model and method.The empirical studies demonstrate the heuristic provides good ship routing and scheduling solutions to real-instances. It can consider both the uncertainty of transportation demands and the seasonal factors of shipping routes. Moreover, the results also show that the voyage arrangement with the consideration of seasonality and weather factors is an efficient way for tramp ship scheduling.