An analytical method is developed to study the sheltering effects on arc-shaped floating perforated breakwaters.In the process of analysis,the floating breakwater is assumed to be rigid,thin,vertical,and immovable and located in water with constant depth.The fluid domain is divided into two regions by imaginary interface.The velocity potential in each region is expanded by eigenfunction in the context of linear theory.By satisfying continuity of pressure and normal velocity across the imaginary fluid interface,a set of linear algebraic equations can be obtained to determine the unknown coefficients for eigenfunction expansions.The accuracy of the present model was verified by a comparison with existing results for the case of arc-shaped floating breakwater.Numerical results,in the form of contour maps of the non-dimensional wave amplitude around the breakwater and diffracted wave amplitude at typical sections,are presented for a range of wave and breakwater parameters.Results show that the sheltering effects on the arc-shaped floating perforated breakwater are closely related to the incident wavelength,the draft and the porosity of the breakwater.