The Crude Oil s logistics in Brasil currently raises faster than last ten years. Driven by new discoveries, in addition to the entry of new players, the problems have been increased in complexity. Thus, an adequate forecast could be interesting to reduce transport s costs by an application of a better strategy for hiring. This paper seeks measure the size of fleet needed for the transport of petroleum in its raw state, providing subsidies to the decision process in oil companies. Therefore are used mathematical modelings considering the various destinations and the commercials contracts. Simulations involving cargo quantities and vehicles routing also had been employed in point of obtaining gains through increasing fleet s efficiency. The purpose of this work is to intend the impacts of some operational problems in scheduling. Two types of services are going to be analysed considering their finalities: the navigation along the Brasilian coast and the navigation between several countries. Finally, fleet will be calculated according to the size of vessel and attempting some different scenarios.