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  2. Echo sounding - Wikipedia

    en.wikipedia.org/wiki/Echo_sounding

    It operates by using a transducer to emit a pulse through the water and listen for echos to return. Using that data, it's able to determine the distance from the strongest echo, which can be the seafloor, a concrete structure, or other larger obstacle. [7] A fishfinder is an echo sounding device used by both recreational and commercial fishers.

  3. Multibeam echosounder - Wikipedia

    en.wikipedia.org/wiki/Multibeam_echosounder

    A multibeam echosounder is a device typically used by hydrographic surveyors to determine the depth of water and the nature of the seabed. Most modern systems work by transmitting a broad acoustic fan shaped pulse from a specially designed transducer across the full swathe acrosstrack with a narrow alongtrack then forming multiple receive beams (beamforming) that are much narrower in the ...

  4. Hydrographic survey - Wikipedia

    en.wikipedia.org/wiki/Hydrographic_survey

    Hydrographic survey is the science of measurement and description of features which affect maritime navigation, marine construction, dredging, offshore wind farms, offshore oil exploration and drilling and related activities. Surveys may also be conducted to determine the route of subsea cables such as telecommunications cables, cables ...

  5. Side-scan sonar - Wikipedia

    en.wikipedia.org/wiki/Side-scan_sonar

    The first commercial side-scan system was the Kelvin Hughes "Transit Sonar", a converted echo-sounder with a single-channel, pole-mounted, fan-beam transducer introduced around 1960. In 1963 Dr. Harold Edgerton, Edward Curley, and John Yules used a conical-beam 12 kHz side-scan sonar to find the sunken Vineyard Lightship in Buzzards Bay ...

  6. Bathymetry - Wikipedia

    en.wikipedia.org/wiki/Bathymetry

    Single-beam echo sounders were used from the 1920s-1930s to measure the distance of the seafloor directly below a vessel at relatively close intervals along the line of travel. By running roughly parallel lines, data points could be collected at better resolution, but this method still left gaps between the data points, particularly between the ...

  7. Identify legitimate AOL websites, requests, and communications

    help.aol.com/articles/identify-legitimate-aol...

    Best practices • Don't enable the "use less secure apps" feature. • Don't reply to any SMS request asking for a verification code. • Don't respond to unsolicited emails or requests to send money.

  8. History of research ships - Wikipedia

    en.wikipedia.org/wiki/History_of_research_ships

    The invention of the echo sounder in 1912 reached a new significance for the international marine research. Henceforth, it was possible to measure the distance to the seabed by sending acoustic signals instead of using wires and weights. Warships used echo sounders during the First World War.

  9. Fisheries acoustics - Wikipedia

    en.wikipedia.org/wiki/Fisheries_acoustics

    Biomass estimation is a method of detecting and quantifying fish and other marine organisms using sonar technology. [1] An acoustic transducer emits a brief, focused pulse of sound into the water. If the sound encounters objects that are of different density than the surrounding medium, such as fish, they reflect some sound back toward the source.