True enough. I started using the NeverLost navigator (for shallow [above 100] reef dives) several years ago.I recommend that, as with computer diving, you make an effort to see the device as convenient, but not entirely reliable. Sonar is affected by reflection and refraction (thermocline and water density factors). When the conditions are ideal, sonar is ideal. When the conditions are not so good, think of sonar as a less than trustworthy advisor...or be ready for a very long surface swim.