A multi-objective fleet routing optimization for passenger shipping among islands

In the last few years the statistical analysis on maritime freight and passenger transport highlights a positive trend of demand and for the next future, given the stressing congestion characterizing the road transport, a further increase both on the deep-sea-shipping and the short-sea-shipping is predicted. Given that, the navigation companies are called to improve their own services to assure a high quality and efficient customers transport, deriving at the same time their own benefits by minimizing the operating costs. Hence, an efficient and careful routes planning activity plays a meaningful role on navigation company productivity and income. Furthermore, the fleet deployment also constitutes a company critical aspect from both the management and maintenance system point of view. Starting from a real case of maritime hydrofoil passengers transport, the tackled problem consists in determining the optimal fleet deployment and the minimum cost routes of a priori known fast vessels fleet in order to satisfy the passengers requests. The passengers splitting is here allowed and, also, vessels are permitted to perform sub-cycles, therefore each port can be reached more than once even by the same vessel. An integer nonlinear multi-objective mathematical programming model is formulated for the fleet deployment and routing design and solved by the Goal Programming Method in order to previously find the minimum size of fleet, successively, the optimal routes and finally minimizing the passengers ride-time. A case study is solved by a commercial software and the results are reported