## 2 Background
[36] compared multi-port-calling (MPC) and H&S strategies for containerships and concluded that H&S benefits the European shipping environment more. [PERSON] et al. [37] investigated the spatial pattern of the worldwide container shipping network and stated its transformation from a multi-port calling system to a multiple regional H&S system, especially for the northern hemisphere. [PERSON] et al. [38] proposed an MILP formulation for solving the liner shipping network hub-location problem in a highly competitive environment. At the same time, [PERSON] and [PERSON] [39] developed an MILP model design of network and fleet deployment of a deep-sea liner service provider incorporating several constraints commonly met in practice. [PERSON] et al. [40] introduced the concept of a main port and several container-shipment-related constants, conjoining a non-convex multi-linear MIP model with genetic algorithms for implementation. [PERSON] et al. [41] established a two-stage logistical gravity model for the H&S logistics network that connects the Chinese insular regions with dry ports in the Belt and Road Initiative context, and [PERSON] and [PERSON] [42] illustrated an MILP model for the H&S network and liner ship fleet planning and applied a Lagrange Heuristic Algorithm to solve the case. Regarding other similar studies in marine transportation, an H&S Roll-on Roll-off freight transport methodology was developed by [PERSON] et al. [43] for interconnecting the shores of the Mediterranean Basin. In a similar direction, [PERSON] [44] presented a mathematical formulation for intermodal chains for handling multiple or conflicting objectives adapted to sea transportation particularities in Chile. Finally, [PERSON] et al. [45] proposed an integrated MIP methodology for the short-sea feeder network design based on the concept of transhipping cargo between main (mother) and secondary (daughter) vessels adapted to the Norwegian sea transportation conditions and needs. Finally, other studies have provided insight for different types of maritime transport operations, such as Arctic Ocean Transportation route planning [46; 47]. Most previous research efforts deal with the conventional H&S problem, adapted mainly to the aviation or cargo transportation fields with the primary characteristic of movement of passengers or cargo between pairs of nodes. In previous works, the optimization goal is typically to minimize the carrier transportation cost, while no specific reference to passenger time and comfort is made. The Short Sea Shipping transportation problem presents specific structural differences from the conventional H&S structure and still remains unexplored. In this problem, serial routes must be designed to serve several nodes (islands) and passenger flows. Passenger-related characteristics like travel time and comfort are considered equally important to transportation costs. This work includes all these elements in a multi-objective optimization approach for the SSS H&S problem. Short Sea Shipping transportation is adapted mainly to the passenger movement particularities of scatter-distributed island regions, such as the Aegean Sea, the Caribbean, Indonesia, the Baltic Sea, etc. Such an SSS network involves short irregular-shaped routes with several intermediate stops prioritizing popular destinations. This network development is similar in principle but different in application from the corresponding one for Artic waterways, which refers mainly to liner shipping networks involving long-distance and rather linear routes within limited navigable waters due to ice.