A chimera Reynolds-Averaged Navier-Stokes (RANS) method has been developed for time-domain simulation of transient flow induced by a ship approaching a berthing structure. The method solves the mean flow and turbulence quantities on embedded, overlapped or matched grids. The unsteady RANS equations were formulated in an earth-fixed reference frame and transformed into general curvilinear, moving coordinate systems. A chimera domain decomposition technique has been employed to accommodate the relative motion between different grid blocks. Kinematic and dynamic free surface boundary conditions were applied on the exact free surface to ensure accurate prediction of the water cushion between the ship and the berthing structure. Calculations have been performed for a two-dimensional ship hull form in lateral motion to demonstrate the feasibility of the chimera RANS approach for time-domain simulation of the hydrodynamic coupling between the ship and berthing structure. The numerical solutions successfully captured many important features of the transient flow around a berthing ship, including the underkeel flow acceleration, wake flow separatum, and water cushion between the ship and harbor quaywall.