What apparatus is used to locate a submerged object?

Solution

Sonar (originally an acronym for Sound Navigation And Ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate,communicatewithordetectobjectson or under the surface of the water, such as other vessels.Twotypesoftechnologysharethename "sonar":passivesonarisessentiallylisteningfor the sound made by vessels; active sonar is emitting pulses of sounds and listening for echoes.