Acoustic sensors, consisting of a concrete anchor and tethered instrument package floating above the anchor, are positioned approximately 915 metres/1000 yards apart along the line. The depth of the floating portion of the instrument varies with local bottom depth. For instruments anchored at less than 150m depth (near shore), the floating portion of the instrument is within 5m of the bottom. For instruments anchored at 150m depth or greater, the instrument package is tethered approximately 150m below the water surface.
