A method for laying an elongated element in a duct using a fluid injected under pressure through a fluid inlet in a pressure housing disposed at the elongated element inlet extremity of the duct. A mechanical drive placed before the pressure housing and the duct pushes the elongated element into the pressure housing and the duct. The method includes installing a first front end pulling pig at the front end of the elongated element and installing at least one subsequent pulling pig around the elongated element. The distance between each pulling pig is mainly constant. The method also includes applying the same maximum pressure drop to each pulling pig. The total pressure of the fluid injected being mainly equally shared by all the pulling pigs.