Disclosed are methods and systems for performing marine geophysical surveys that utilize a streamer having variable stiffness. An embodiment discloses a sensor streamer comprising: an outer surface; tension members within the outer surface extending along a length of the sensor streamer; spacers disposed within the outer surface along the length of the sensor streamer; a geophysical sensor disposed in an interior of one of the spacers; and an actuator assembly configured to apply tension to the tension members.