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Multibeam Echosounder
FAIRWEATHER has two hydrographic survey launches equipped with retractable hull mounted RESON SeaBat 8101 multibeam echosounders. These are used in waters up to 100 meters deep and in areas where it would be difficult for the ship to navigate. The ship is outfitted with two hull mounted sonars. A RESON SeaBat 8111 is used in areas up to 400 meters deep, and a RESON SeaBat 8160 is used for deep ocean surveys. |
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The multibeam echosounders used by the FAIRWEATHER are hull mounted instruments that emit acoustic waves in focused beams. These beams form wide swaths that track depths on the ocean bottom. Bathymetric data, or depth measurements, are generated by measuring the time it takes for the sound pulses to travel through the water to the bottom and back to the instrument. The distance from the instrument to the ocean floor is calculated by multiplying this travel time by the speed of sound through water. It is important to have an accurate measurement of the speed of sound through water for data to be valid. To learn more about multibeam echosounders visit:
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The speed of sound through water is affected by the conductivity, salinity, temperature, and pressure of the water. All of these factors change throughout the water column. During hydrographic surveys, a CTD (Conductivity, Temperature, Depth) probe is used to measure these components on a regular basis. The measurements are processed to create a sound velocity profile, which is later applied as a corrector to the data. |
