Do you guys know about Depth Sounders:
Depth sounding refers to the act of measuring depth. It is often referred to simply as sounding. Data taken from sounding are used in bathymetry to make maps of the floor of a body of water, and were traditionally shown on nautical charts in fathoms and feet. The National Oceanic and Atmospheric Administration (NOAA), the agency responsible for the bathymetric data in the United States, still uses fathoms and feet on nautical charts.
Some examples of Depth Sounders are shown below:
Navigation Technologies – Model: D999
Raytheon Marine Co. – R8220