Navigation General · Depth Sounding — Echo Sounder
An echo sounder (depth sounder) determines water depth by measuring:
- AWater temperature
- BSalinity
- CGPS altitude
- DThe time for a sound pulse to travel to the bottom and return✓ Correct
Explanation
A transducer emits a sound pulse and times its echo from the seabed; knowing the speed of sound in water, the set converts the round-trip time to depth. The navigator must know whether the readout is depth below the keel or below the transducer/waterline.
Authority: Bowditch
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