Rough weather conditions can significantly affect the ship's operational capabilities, in terms of energy efficiency, safety, and comfort on board. With the aim to improve both the ship energy efficiency and the operability, the authors developed a voyage optimization methodology based on real weather forecast maps. This paper presents an overview of the different aspects of the voyage optimization, focusing on the operational implications of the developed method. The routing problem is parameterized in a discrete space-time domain, and the minimum fuel consumption routing solution is selected by means of a dynamic programming optimization algorithm, in compliance with the existing geographical, propulsive and operability constraints. Ship seakeeping and propulsion system is modelled to realistically estimate the propulsion performances and fuel consumption, as well as a number of ship motions-related operability indices, associated with a given sea state and wind condition. Eventually, a case study is shown, and a number of simulations in different operating scenarios are critically discussed.
Maritime voyages are significantly influenced by the weather conditions: in the recent years, the reliability of weather forecast models has significantly improved the safety of ship voyages, allowing operators to plan convenient routes to avoid rough weather and to estimate the costs associated with the voyages.
Moreover, increased attention is paid nowadays to seakeeping abilities of ships, thus increasing the ship safety also in rough weather conditions, as well as the operability in medium intensity weather conditions that can affect fuel consumption and comfort on board.
The concurrent addressing of ship efficiency, ship routing, ship safety and comfort issues can be handled numerically, in real-time, providing a relevant decision support tool. In this framework, optimization algorithms find their application, in order to provide a significant support to the decision making process; they allow the integration of multiple aspects of a process and to optimally select with respect to the objective. Ship and human safety, fuel consumption, energy efficiency, crew and passenger's comfort, voyage time, control of delays - these are all different aspects that contribute to formulate the overall objective (cost function) of the ship voyage. The "optimal voyage" is the one associated to the minimum value of the cost function, within the constraints of the problem.
