Maneuverability of a pusher and barge system under empty and full load conditions

Abstract

A pusher–barge system (P/B) has been one of the main transportation systems particularly for rivers and inland waterway services. Since a P/B normally sails in restricted waters such as a sharp bend in a river, the maneuverability is important for safe navigation. Although the barge draft changes drastically with an increase of the amount of cargo, the draft of the pusher which normally equips a small ballast tank does not change so much. It indicates that the step appears or disappears around the pusher–barge connection due to the load condition of the barge. This phenomenon is a unique and interesting characteristic of a P/B. Therefore, this study aims to discuss the effect of the barge load condition on the maneuverability. For this purpose, the towing tank experiments were conducted under the empty and full load conditions of the barge, and the mathematical model to simulate maneuvering motions of the P/B was established. At that time, the hydrodynamic force data in the range of high yaw rate was made up by the CFD method. We found that the course stability of the P/B deteriorated with an increase of the barge draft. It is related to the change of the pressure filed spread over the pusher bow which is influenced by the wake shed from the barge. Besides, the simulation study revealed that the turning ability due to small steering was worse under the empty load condition than the full load condition of the barge. However, it appears to be improved with an increase of the steering angle.