A Contribution to Optimum Selection of Fleet-Size (II)

Abstract

In the previous paper, basic mathematical models relating the transport costs to a fleet were developed for the case of crude oil carriers, and a problem was solved to determine the optimum fleet-size to meet a transport demand in an arbitrary route with one port loading and one port unloading, where the fleet was assumed to be composed of identical type ship. In this paper, some improvements are made of the mathematical models so that a route selection problem may be treated. Further, a different optimization procedure is developed, by which the fleet that does not necessarily consists of identical type ship can be optimized. For this purpose, the concept of dynamic programming and nonlinear programming techniques are applied, and a versatile software program is developed. The effects of various factors in transportation system, such as the transport demand, the draught limits, the tolls, the storage costs at terminals, etc., are discussed concerning the resulting optimum fleet-size.