The article presents a simulation method for determining the minimum safe pull of tugs assisting in port manoeuvres. The method can be used to determine the relationship between the minimum safe pull, understood as the tension on the line, of the assisting tugs and the overall length, cargo capacity or net capacity of ships manoeuvring in a given port under allowable hydrometeorological conditions. The method was verified through simulated tests of gas tankers’ entry, turning and berthing at the LNG terminal of Świnoujście