A Review of Ship-to-Ship Interactions in Calm Waters

The hydrodynamic interaction between two or more ships in harbours or inland waterways is a classical maritime engineering research area. In ship manoeuvring practice, ship masters try to determine the speed and gap limit when a ship is passing or encountering others, particularly in confined water ways. This requires an accurate prediction of the interaction force acting on both ships. The pioneer experimental studies showed that the interaction could lead to a very large yaw moment and this moment is strongly time-dependent, which could make the ships veer from their original courses, leading to collisions. Based on the findings on experimental measurements, some empirical formulas are proposed in the literature to predict such interaction forces. However, these formulas could provide a satisfactory estimation only when the ship speed is quite high, and the water depth is shallow and constant. Numerical simulation overcomes this issue by simulating the ship-to-ship problem by considering the effect of the 3D ship hull, variable water depth and ship speed. Numerical simulation has now become the most widely adopted method to investigate the ship-to-ship problem. In the present study, the development of the methodologies of ship-to-ship problems will be reviewed, and the research gap and challenges will be summarized.