Echo sounder and Fathometer

Echo sounder noun - A measuring instrument that sends out an acoustic pulse in water and measures distances in terms of the time for the echo of the pulse to return.

Fathometer and echo sounder are semantically related in sounder topic. In some cases you can use "Fathometer" instead a noun phrase "Echo sounder".

Fathometer noun - Depth finder for determining depth of water or a submerged object by means of ultrasound waves.

Echo sounder and fathometer are semantically related in sounder topic. You can use "Echo sounder" instead a noun "Fathometer".