sonar performance

raduz · 08-06-07, 04:45 AM

This is what I found on wikipedia:
http://en.wikipedia.org/wiki/Sonar

"Sound waves that are radiated down into the ocean bend back up to the surface in great arcs due to the increasing pressure (and hence sound speed) with depth. The ocean must be at least 6000 feet (1850 meters) deep, or the sound waves will echo off the bottom instead of refracting back upwards, and the loss at the bottom reduces performance."

Then why the DDs were able to ping the subs even in shallows water?

08-06-07, 04:45 AM	#1
raduz Engineer Join Date: Sep 2006 Location: Slovakia Posts: 205 Downloads: 3 Uploads: 0	sonar performance This is what I found on wikipedia: http://en.wikipedia.org/wiki/Sonar "Sound waves that are radiated down into the ocean bend back up to the surface in great arcs due to the increasing pressure (and hence sound speed) with depth. The ocean must be at least 6000 feet (1850 meters) deep, or the sound waves will echo off the bottom instead of refracting back upwards, and the loss at the bottom reduces performance." Then why the DDs were able to ping the subs even in shallows water?