Sonar Technology Bottom Lock

Bottom lock is a display mode that keeps the bottom fixed at a consistent position on your screen and shows only a user-defined range above it. Instead of the standard depth-based view where the surface is at the top and the bottom varies in position as depth changes, bottom lock anchors the bottom line and magnifies the water column immediately above it.

This mode is invaluable for finding fish that hug the substrate, species like walleye, lingcod, flounder, and catfish that often sit within inches of the bottom and would be lost in the dead zone on a standard view. By expanding the near-bottom zone to fill more of your screen, bottom lock makes these close-to-bottom targets visible and distinguishable from the bottom return.

The user sets a range — for example, 10 feet — and the display shows only the bottom 10 feet of water regardless of actual depth. Whether you are over 15 feet or 50 feet of water, the bottom stays in the same screen position, and only the bottom 10-foot window is displayed. This makes it easy to spot fish that would otherwise blend into the bottom signal.

Bottom lock works best when used alongside a standard view on a split screen. One panel shows the full water column for general awareness, while the bottom lock panel provides a magnified view of where the bottom dwellers are sitting. This combination gives you the best of both perspectives without missing anything in the upper water column.