A depth finder that uses sound waves to determine the depth of water.(noun)
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Use "fathometer" in a sentence
"The fathometer was the only operable piece of equipmentdespite having stopped working briefly right after the attackbut the depth finder could do little to guide the injured Liberty."
"The ships fathometer, which for a while only functioned on the hundred-fathom scale, revealed the Liberty entering shallow waters."
"A fathometer and a compass were bolted to the overhead."