When designing berths and ship mooring systems near berths, it is necessary to protect ships from dangerous displacements. To make a well-reasoned choice, it is necessary to make estimates of the characteristics of sea wave impact on the ship (with respect to the steady-wave mode in the waters). The results of numeric calculations are better suited for engineering purposes. This paper presents a mathematical model to estimate hydrodynamic characteristics of wave impact on the ship moored at the berth with a stilling pool. To derive this mathematical model, the analytical method using eigenfunction expansion was employed. Also, the article shows the calculation data to demonstrate the influence of berth characteristics on loads experienced by the ship.