Humminbird 3000 Deep, 3005 Thermoclines Fish Appearance, Chart Window / Bottoms / Fish Appearance

Thermocline

Slope

Second

Return

Thermoclines

The LEGEND 3000 SERIES is also capable of showing layers of water having different temperatures. These temperature differences, called thermoclines, appear at different depths, depending on current conditions. A thermocline typically appears as a continuous band of many gray levels moving across the display at the same depth. Thermoclines always appear above the bottom.

Fish Appearance

Schools of bait fish as well as individual fish are clearly visible on the LEGEND 3000 SERIES display. Bait fish appear as “clouds” having different shapes and sizes depending on the number of fish and boat speed. Individual fish appear as smaller black and gray lines, often appearing as a “fish arch.” A fish arch may form as the fish moves through the sonar beam. Due to the transducer beam angle, the distance to the fish decreases as the fish moves into the beam, and then increases as it moves out again. When the CHART WINDOW graphs this distance change, an arch appears. Boat speed, the CHART SPEED setting and movement of the fish greatly affect the shape of the arch. When the boat and the fish are moving slowly relative to each other, the fish creates an elongated arch. When the boat and the fish are moving quickly relative to each other, the fish creates a shorter arch. A partial arch forms when the fish does not move through the entire cone angle.

USING THE LEGEND 3000 SERIES

CHART WINDOW / BOTTOMS / FISH APPEARANCE

Note: It

i	s
Bait fish
Fish Arch
Partial Fish
Arch
Structure

important to remember that sonar cannot distinguish between a fish and some other object suspended in the water. Regardless of the object the sonar detects, it has the possibility of being drawn as an arch.

Sonar Views (Deep Models Only)

The dual beam (50/200kHz) sonar information can be displayed in several different views in the CHART WINDOW. In the 200kHz view, only the sonar returns and FISH ID from the 200kHz beam are displayed. Typically, the 200kHz information provides greater bottom detail up to 800' and works well while the boat is in motion. The 50kHz view only shows the sonar returns and FISH ID from the 50kHz beam. The 50kHz information provides depth accuracy up to 2000' and shows more targets in its wider beam. The Split Screen view shows the 50kHz and 200kHz sonar information in side-by-side windows on the display. The 200kHz/50kHz view is a composite of the 200kHz sonar information and the target information from the 50kHz sonar. See CONTROL PANELS for details on selecting the sonar views.

Fish Arch Diagram

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