Study on total resistance of ships navigating in shallow water

This study predicts the resistance of the oceangoing KCS containership and the inland waterway Heniu121 models, establishing a testing platform for varying water depths. The effects of water depth, Froude number, and Reynolds number on resistance are analysed. A key contribution of this study is the development of an improved ITTC57 flat plate friction formula and refined form factor fitting specifically designed for shallow water conditions. In addition, a novel three-dimensional method for extrapolating model-to-full-scale ship resistance in shallow water is introduced, effectively capturing shallow water effects on ship resistance. The results suggest that frictional resistance is closely related to the operating speed and water depth. Moreover, a comparison between the two representative hull types investigated indicates that hull shape also affects frictional resistance. When h/T (Water depth/Draft) = 1.2, the proportion of frictional resistance in total resistance decreases by 20 %.The conventional ITTC57 flat plate friction formula shows limited applicability in shallow water, with a 13 % error observed at h/T = 1.2. Finally, the improved ITTC57 formula and form factor fitting enhance extrapolation accuracy by 6 %–30 % in shallow conditions. This study provides a scientific basis for ship resistance prediction in shallow water. • The resistance of the KCS and the inland waterway models is obtained for varying water depths. • An improved ITTC57 flat plate friction formula and refined form factor fitting for shallow water conditions are proposed. • A novel three-dimensional method for extrapolating model-to-full-scale ship resistance in shallow water is introduced. • It was shown that ship frictional resistance is closely related to hull shape, operating speed, and water depth. • A novel framework is introduced for ship resistance prediction in shallow water.