Depth gauge and Sonic depth finder

Depth gauge noun - A gauge for measuring the depth of grooves or holes or other concavities.

Sonic depth finder and depth gauge are semantically related in sounder topic. In some cases you can use "Sonic depth finder" instead a noun phrase "Depth gauge".

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

Depth gauge and sonic depth finder are semantically related in sounder topic. You can use "Depth gauge" instead a noun phrase "Sonic depth finder".