Comparison study of a pusher–barge system in shallow water, medium shallow water and deep water conditions

The study of pusher–barge system in this paper is a continuation research of nine different pusher–barge systems and eight unconventionally arranged pusher–barge systems (Yasukawa et al., 2007; Koh et al., 2008a and Koh et al., 2008b). In this study, pusher–barge system with one pusher and one barge arranged in a linear combination (11BP) was brought into shallow water condition and tested at Kyushu University, Japan with water height to ship draught ratio (h/d): 1.2 (shallow water); 1.5 (medium shallow water); and 19.3 (deep water) conditions. Least squares' fitting method was used in determining the hydrodynamic derivatives that are suitable for the three water draught ratio conditions. Linear derivatives from the experiments were compared with studies from different researchers ( Fujino and Ishiguro, 1984, Yoshimura, 1986 and Yoshimura and Sakurai, 1989). Added mass was calculated using singularity distribution method under the assumption of rigid free surface. Propeller and rudder hull interaction parameters were pre-assumed based on the study of other researchers. In the study, negative course stability was found in shallow water condition (unstable in course keeping). Maneuvering simulations at 20° and 35° turning show that pusher–barge 11BP has the largest turning circle in deep water condition and smallest turning circle in shallow water condition. Course keeping ability decreases from deep water to medium shallow water to shallow water conditions.

► Pusher–barge system was tested in deep water, medium shallow water and shallow water condition.
► Rotating arm test was conducted in Kyushu University.
► Computer simulation was carried out using the captured hydrodynamic derivatives.
► Pusher–barge 11BP system was found to decrease in turning trajectory from deep water to shallow water condition.