Marine survey. The various embodiments includes both methods and systems. At least some of the illustrative embodiments are methods including: deploying a spreader structure from vessel into a body of water, wherein the spreader structure defines a deployed width of one kilometer or more; coupling a plurality of sensor streamers to the spreader structure; and towing the plurality of sensor streamers through the water, where the horizontal separation between the sensor streamers is at least partially maintained by the spreader structure. The spreader structure provides horizontal separation sensor streamers without the use of a tensioning force applied to the spreader structure.