Methods and systems for efficiently acquiring towed streamer seismic surveys

A method comprising:

• (a) deploying a marine seismic spread comprising a source-streamer tow vessel towing one or more marine seismic sources and one or more seismic streamers, a port source-only tow vessel, and a starboard source-only tow vessel;
• and
• (b) positioning the source-only tow vessels and the source-streamer tow vessel to acquire a wide- and/or full-azimuth seismic survey without need for the spread to repeat a path once traversed, and acquiring two source lines of marine seismic data simultaneously with split-spread configuration.

A system comprising:

• (a) a marine seismic spread comprising a plurality of source-only tow vessels each adapted to tow one or more marine seismic sources without streamers, and one or more source-streamer tow vessels each adapted to tow one or more marine seismic sources and one or more seismic streamers;
• (b) the source-only tow vessels and the source-streamer tow vessels adapted to be positioned to acquire a wide- and/or full azimuth seismic survey without need for the source-streamer vessels to repeat a path once traversed.

21-40. (canceled)