In recent years, with the development of new ships and further utilization of marine resources, multi-body floating systems are widely used in practice. Compared with the single floating body, the movement in multi-body floating system is not only affected by the external environment, but the interaction between the bodies cannot be neglected. So analysis of hydrodynamic performance of a multi-body floating system is of great importance.
In this paper, a multi-body system consisting of two side-by-side ships is studied. The code AQWA® is used for its hydrodynamic performance analysis in frequency domain. Its hydrodynamic parameters are compared with those of the related single-ship system and the difference is obvious. The two-ship system shows a peak in motion different from single-ship system at some frequencies and its wave exciting forces have period effects. Also, negative values appear in added masses, which never occur for a single-body floating system. When the gap between the two ships is changed, there is a significant trend that the wave frequency of the peak value decreases with the gap size between the two ships.
In addition, this paper also discussed the length of wave and distance of ships ratio that the motion resonance usually happens. Through the analysis of this dimensionless parameter, a conclusion about resonance between two parallel ships is deducted.