The modelling of shipping freight markets. The application of the methodology of system dynamics to the modelling of behaviour in world shipping freight markets, and to decision-making in medium sized shipping companies.

Abstract

The world shipping freight market for the transportation of bulk cargo - liquid and dry - is characterised by the somewhat erratic and extreme fluctuations exhibited by many of the measures that can be used to describe the "state" of the market. Such 'measures' include the spot freight rates - the cost to the shipper of chartering a unit of shipping capacity 'on the spot' (that is, not reserving the vessel in advance), - the proportion of chartered tonnage at any time taken on a period (time) basis as opposed to a voyage (single) basis, and the rate at which orders for new vessels reach the shipyards. These factors are extremely variable, and have exhibited a similar form of behaviour for a large number of years. This present thesis describes an attempt to investigate the behaviour of the freight market (bulk cargo); the aim of the investigation being to identify the structure of the market system and to construct a System Dynamics model which describes the complex relationships in the market and which can be used to explore questions relating to present or future market behaviour. The construction of such a model is described, together with an exhaustive chapter on the analysis of the model, covering loop-analysis, the behaviour of the model under various test inputs, and the senstivity of the model to significant changes in parameter values. The final chapter considers the use of the model, and, in particular, describes its use in an investigation of the feasibility or desirability of introducing tonnagestabilization schemes into the market. Such schemes aim to prevent the freight rates from falling to unacceptably low values, by implementing a scheme whereby tonnage is withdrawn from operation and laid-up: the decrease in the supply of tonnage then has a positive influence on the freight rates. It is concluded that the problems involved in designing such schemes preclude the schemes from implementation. The appendices cover the various data used in the determination of market relationships, as well as the computer listing, in Fortran, of the market model. Also included in an appendix is a description of the application of System Dynamics to a hypothetical company. The tcompany model' allows for the examination of chartering policies and lay-up policies under a variety of conditions of market demand.