CNN New Day April 10, 2014 10:08:00
20,000 feet. >> yeah. the advantage of these buoys, the sonobuys is they can hang just below the thermolayer. above that you can block the sound because the density of the water is different. these can be very quiet. there's no ship at all. these have no ship attached. they are dropped by an airplane and that's fantastic. just perfect quiet. >> the quiet is an important part of this, mary, because we have the "ocean shield" which obviously has been taking the lead in trying to track the pings and further pings. we've also been told the hms echo was going to be moved into that area. i found tha...