Humminbird HELIX 9 Operation Manual page 55

Turn on/off Bottom Lock
Use Bottom Lock and Bottom Range to focus on the bottom and control how much of the water column is shown in Sonar Zoom View.
Bottom Lock continuously graphs the bottom at a constant point on the display regardless of changes in depth. This "flattens" out the
bottom contour but is effective at showing fish on or near the bottom.
1. Sonar X-Press Menu: With a Sonar Zoom View displayed on-screen, press the MENU key once.
2. Select Bottom Lock. Press the RIGHT Cursor key to select On.
3. Press the UP Cursor key. Select Bottom Range.
4. Press the RIGHT or Left Cursor keys to adjust the range. The range is measured up from the bottom.
Low Setting: useful for seeing low-lying bottom structure or details of the bottom return.
High Setting: useful for seeing large structure in deeper water.
NOTE: If you see a wavy band on the view that mirrors the change in depth, the Bottom Range might be set deeper than the actual
water depth. In this case, decrease the Bottom Range setting.
Change the Width of the Zoomed View
Use the instructions in this section to change the width of the zoomed view in Sonar Zoom View.
1. Main Menu: Press the MENU key twice. Select the Sonar tab.
2. Select Zoom Width.
3. Press the RIGHT or LEFT Cursor keys to adjust the setting.
zoomed
view
Setting the Bottom Range and Zoom Width (Bottom Lock On)
zoom width (wide)
55
full range
zoom
preview,
bottom
range
Sonar (2D)