System for controlling cables and streamers in a seismic tow arrangement comprising at least one deflector (13) connected to one side of a tow vessel (10) via at least one wire (12), leading or the like, wherein the deflector is located in a position at a distance perpendicularly to the direction of movement (5) of the tow vessel, the vessel being equipped with a navigation system for measuring the position of the vessel. The system is characterised by comprising a command unit and a number of control units, where the control units are located on at least some of the streamers and are adapted to measure and report about their positions, that the command unit comprises means for receiving the position information from each individual control unit and calculation of possible deviations from predetermined positions, and that the system comprises means for changing the position of the streamers for re-establishing the positions of the control units.