AbstractAs part of the research focusing on the safety of vessels during the lockage in navigation locks, two different 1D numerical modeling approaches were tested. These approaches are used to determine the force effects on vessels during the direct filling process of the navigation lock. These numerical models were verified using data measured on a physical model. Using the selected 1D model, a parametric study focusing on the impact of the basic parameters of the navigation lock including the lifting velocity of the gates on the maximum hawser forces was performed. The research has shown that with a suitable design of the upper gate, the direct filling system may also be used for medium-head navigation locks with a normal lift of up to 5 m.