This paper presents a corrected partitioned scheme for investigating fluid–structure interaction (FSI) generated by ship squat in presence of transient effects. A theoretical example describing the motion of a piston enclosed in a U-tube gives rise to an analysis of the divergence effect resulting from added mass, and it has been concluded that divergence always occurs when the mass in motion is less than the added mass. An added- mass-corrected scheme is proposed to guarantee the convergence of the coupling scheme irrespective of the mass ratio. This corrected scheme is successfully applied to the ship dynamics in an analysis of ship squat via a non-stationary potential fluid flow approach. The results of our coupled calculations have been compared to the squat stability models detailed in Alderf et al. (2010); Alderf et al. (2015) in which transient effects were neglected in the fluid flow solver. Finally, energy transfers between the ship’s motion and the fluid flow have been analyzed. We confirm the energy conservation capability of the proposed fluid–structure coupling scheme in relation to the transient response of the ship.