Navy ships use sonar to detect submarines. A sound pulse sent by the ship reflects off the submarine. If the submarine is 2200 m away from the ship and the speed of sound in seawater is 1400 m/s, how long will it take the sound pulse to travel out AND back? Navy ships use sonar to detect submarines. A sound pulse sent by the ship reflects off the submarine. If the submarine is 2200 m away from the ship and the speed of sound in seawater is 1400 m/s, how long will it take the sound pulse to travel out AND back? 1.57 x 10-3 s 1.57 s 3.1 s 3.1 x 105 s