The Dynamic RORO Stowage Planning Problem

The shipping industry's greenhouse gas emission reduction has received significant focus over the past years. One of the research areas is that of stowage planning for RORO vessels. Efficient stowage plans are necessary to reduce the turnaround time for vessels in a port. Reducing turnaround time results in prolonged sailing time, allowing vessels to reduce fuel consumption through slow steaming. When RORO vessels have calls at several ports, they handle cargo as an approximate FILO queue. Therefore, cargo can potentially become blocked when stowing cargo for later ports, behind cargo with an earlier discharge port. Planning the cargo assignment onboard the vessels also requires considering the arrival time of cargo at the port. Recent research assumes that all freight is available for stowage when the RORO vessels arrive at the port. However, this is not always the case. The unique elements of scheduling and generation of loading/discharge paths are therefore of academic interest. We propose a novel mathematical model with a weighted objective function that minimizes the relationship between the fuel consumption cost and the revenue gained from shipping cargo. The model schedules the cargo loading sequence to reduce time spent handling and re-handling cargo at each port. The problem is studied for a single deck layout for a vessel calling multiple ports. Results of the mathematical model and accompanying metaheuristic will be presented.