Simply by measuring the time it takes for the sonar 'ping' to return to the device that sent it. The speed of sound is constant - and dividing the time by the speed of sound gives the distance !
Sea Songs for Landlocked Sailors was created in 1999.
The depth of the sea can be determined by measuring the time taken for sound waves to travel from a source to the seafloor and back to a receiver. By knowing the speed of sound in water, scientists can calculate the distance to the seafloor based on the time taken for the sound waves to return. This method is known as echo sounding or sonar.
The speed of sound in water is affected by temperature, salinity, pressure, and depth. Typically, the speed of sound increases with depth due to increased pressure, so it is likely louder at 300 feet below sea level compared to 200 feet.
SAILORS!
no human can live in the depth sea
the density of sea increases with depth
great sailors
no human being can live on the depth sea
Sailors call long sea journeys by sea "Voyages"
sailors measure distances at sea in nautical miles
Echo sounding measures the time it takes a sound wave to hit the sea floor and return, knowing the speed of sound in water allows a depth to be calculated, if you have an existing depth map and a GPS , any differences between the map and your reading, could indicate a shoal of fish has sent back a false depth reading.