A seismic survey system includes a winch having a winch cable coupleable to a source array towable between two deflected lead-ins, a positioning system for determining a current position of the source array and a controller for adjusting the winch to modify the current position of the source array to a desired crossline position. The winches may be attached to the deflected lead-ins or mounted on a tow vessel. The winches exert lateral forces on the source array, derived from the deflected lead-ins, to control the inline position of the source array. A method includes positioning a seismic source array in tow behind a vessel comprises determining a current position of the source array and adjusting a lateral force applied to the source array to move the source array to a desired crossline position. Optionally, by adjusting the gun cable winch, the inline position may be controlled.