Fathometer and Sonic depth finder

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

Sonic depth finder is a synonym for fathometer in sonar topic. In some cases you can use "Sonic depth finder" instead a noun "Fathometer", when it comes to topics like echo sounder, sounder.

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

Fathometer is a synonym for sonic depth finder in sonar topic. You can use "Fathometer" instead a noun phrase "Sonic depth finder", if it concerns topics such as echo sounder, sounder.