Using Bottom Lock - Raymarine L1250DRC Owner's Handbook Manual

Chapter 5: Adjusting the Display
If you choose split, the scrolling bottom is displayed in both frequencies
with 200 kHz in the upper window and 50 kHz in the lower window.
3. If necessary, press the AUTO FREQ OFF ON soft key to select AUTO fre-
quency. AUTO frequency is indicated by the letter F in the status bar.
4. Press ENTER or CLEAR to return to the default display.
You can choose the split frequency display with the fishfinder display options,
Bottom Lock, A-Scope, or Zoom.

Using Bottom Lock

The scrolling bottom display provides a top-down view, referenced from the
surface of the water. Bottom Lock shows a water column of fixed height,
referenced from the bottom, that appears flat. It removes bottom detail to
provide an image of objects directly above the bottom and is useful when you
are looking for fish that feed close to the bottom.
You can select the Bottom Lock image to be vertically split with the scrolling
bottom display, or it can replace the scrolling bottom display.
As illustrated in Figure 5-7, the bottom is shown as a straight line. Note that
some bottom features may extend above this line. The actual depth reading is
given in the bottom left hand corner of the Bottom Lock display.
Range intervals on Bottom Lock are measured up from the bottom (rather than
down from the surface). Thus, the bottom is shown as zero and the top number
indicates the maximum distance above the bottom being displayed. You can
adjust the Bottom Lock range.
If the A-Scope or Zoom image was displayed, selecting Bottom Lock
automatically switches OFF A-Scope and Zoom.
If you have split frequency selected, the Bottom Lock image is displayed in
both frequency windows.
If Target Depth ID is ON (see Target Depth ID on page 4-14), the target depth
is displayed as distance from the bottom.
➤ To display the Bottom Lock image:
1. Press the BTM. LOCK soft key. The Bottom Lock selection soft keys are dis-
BTM.LOCK
played.
2. Press the BTM. LOCK OFF ON soft key to toggle the function ON.
3. Press the BTM. LOCK FULL SPLIT soft key to toggle between a full window
bottom lock image or split windows. The bottom lock image is displayed.
If you select split windows, the fishfinder display is split vertically, with
the bottom lock image in the left hand window and the scrolling bottom
display in the right hand window.
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