In this paper, the ship lock entry problem is studied, which is physically similar to, but numerically different from, the water entry problem simulated by the author 25 years ago under the instruction of Prof. He. A one-dimensional unsteady hydraulic narrow-channel model for the flow coupled to the ship's motion in surge, heave and pitch is formulated and numerically implemented. The calculated ship motions were validated by comparison with model experiments carried out in the Duisburg shallow water tank. The viscous effects are further taken into account in order to investigate the scale effect in the experimental modeling in a framework of new lock project of Panama Canal. Thus, the experimentally validated model is applied to optimize the lock entry time by changing the trust course in the full-scale case.