1 | Introduction
Ship speed has merited consideration for as long as ships have been employed as the vehicle for maritime transportation, in view of its bearing on fuel costs, and consequently on the competitive position of maritime tranportation vis-a-vis other modes of transportation, such as road and rail. As Lavon and Shneerson1 have pointed out, ship speed is considered in two distinct time instants of ship lifetime: ship design and ship operation. The role of ship speed in ship design is treated analytically by Jansson and Shneerson2 in the context of liner shipping. The concern of the work reported in this paper is confined to the role of ship speed in ship operation, and as such, the focus of this paper is on the role that ship speed plays in maritime transportation planning. As stated by Chistiansen et.al.3, “maritime transportation planning problems can be classified in the traditional manner according to the planning horizon into strategic, tactical and operational problems”. In view of the temporal variation of cargo transport demand, port bunker fuel price variation, market competition between ship operators, ship route planning, ship fleet sizing and deployment, and increasing environmental concern with regard to greenhouse gas emissions, the role of the ship speed optimisation problem in maritime transportation planning has been been greatly enhanced. This has resulted in the formulation of several ship speed optimisation problem variants4,5, as well as the development of a varirty of solution methods6.