A methodology to assess vessel berthing and speed optimization policies

Standard ocean shipping contracts stipulate that a chartered vessel must sail at ‘utmost despatch’, with no consideration for the availability of berths at the destination port. The berthing policies used at many ports, which admit vessels on a first-come, first-served basis, provide an additional incentive for the master to sail at full speed. These legacy contracts and berthing policies constitute a major driver of harbour congestion and marine fuel consumption, with adverse economic, safety, and environmental consequences. We propose a methodology to evaluate the potential benefits of new berthing policies and ocean shipping contracts. Given the importance of stochasticity on the performance of maritime transport systems, and the need to represent the efficient allocation of terminal resources, we have chosen a hybrid simulation-optimization approach. Our discrete event simulation model represents vessels and their principal economic and physical characteristics, the spatial layout of the terminal, performance of the land-side equipment, contractual agreements and associated penalties, and berthing policies. The proposed optimization model – a substantial extension of the traditional berth assignment problem – represents the logic of the terminal planner. The simulation program solves multiple instances of the optimization model successively in order to represent the progression of planning activities at the terminal.