Joint optimization of strategic fleet planning and contract analysis in tramp shipping

Maritime transportation is one of the most capital-intensive industries. Fleet planning is vital but challenging to shipowners because the industry is extremely volatile. Relatively few papers have studied strategic fleet planning in tramp shipping, which is intertwined with contract analysis and different from that in industrial or liner shipping. This article develops a mixed-integer programming model, and it is the first of its kind that jointly optimizes strategic fleet planning and the selections of long-term and spot contracts in tramp shipping. The model can be used to determine the best mix of long-term and spot contracts for a given fleet and/or to find the optimal fleet size and mix for a set of contracts. It can be used as a basis for a fleet renewal programme, informing decisions on when to sell, whether to buy old or new ships, and when to charter in or out vessels. A numerical example is given to illustrate how to use the model to evaluate different operations strategies.