Garmin 376c Manuale Proprietario

The transducer mounted on your vessel transmits sound waves 

toward the bottom of the water in a cone-shaped pattern. When 

a transmitted sound wave strikes an underwater object—such as 

the bottom, a structure, or a fish—sound is reflected back to the 

transducer. The transducer collects the reflected sound waves and 

sends the data to the GSD 20 Sounder Module and then to the 

GPSMAP 376C to be processed and displayed. The underwater data 

is shown on the Sonar display in the order that it is returned; first 

returned is the first on the display. 

Generally speaking, if the only thing between the transducer and 

the bottom is water, the first strong return comes from the bottom 

directly below the transducer and sets the bottom level. Weaker 

secondary returns provide the detailed data. Stronger returns display 

in darker colors, with red being the strongest return.

One of the first things to understand about sonar is that the 

transducer sends a beam down to the bottom of the water, much like 

the beam of a flashlight. The beam starts small near your vessel and 

 for 

more detailed information.
The Sonar Page does not display a three-dimensional representation 

of the underwater environment; the display is in two-dimensions, 

much like if you took a picture of an aquarium. Only the depth of 

the item in the water appears. The Sonar display does not show you 

where an item is located horizontally in the water, as shown in the 

drawings below. The fish is not directly above the tree in reality, but 

it might look like it is on the Sonar Page.

20'

10'

1'

Fish

Tree

Tree

S

ETTING

 

UP

 

AND

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SING

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ONAR

 > 

U

NDERSTANDING

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ONAR