How to Read a Depth Finder

How to Read a Depth Finder
Depth finders, which use SONAR, have become a hot commodity. Manufacturers make grandiose claims about how the units, usually called fish finders, can help you quickly and efficiently find fish and spend less time making useless casts. While it is true that a depth finder can be used to locate fish under the water, knowing how to properly operate one is key to the success or failure you will have with it, and experience with a depth finder will make you much more adept with it.


Difficulty: Moderately Easy

Things You’ll Need:
  • Depth finder Boat
  • Depth finder
  • Boat
Step 1
Turn off the fish symbols mode on your depth finder. Leaving it on will create a more cluttered and confusing display.
Step 2
Adjust the sensitivity to approximately 80 percent and look at the screen to see how much shows up. Depending on what is in the water, the display should give a pretty good representation of what's underneath the boat. Familiarize yourself with the display at different sensitivities as well, to better understand the capabilities of your unit. Some units have an automatic mode that works well in many situations.
Step 3
Look at the display to figure out where the bottom is. The bottom will show up as a line on the bottom of the screen, and may be uneven, depending on what the boat is passing over. If the line is defined, it is a hard bottom, but thinner, more nebulous lines are a soft bottom.
Step 4
Look for the arches; arches in the water will be fish, but they will only show up as a full arch if the fish is in the middle of the depth finder's beam and if either the boat or the fish is moving. Partial arches in the water, or lines, may indicate fish that are not moving in relation to the boat.
Step 5
Know the habits of the fish you are looking to catch. This will help you determine whether the arch is likely a fish or something else.
Step 6
Practice repeatedly with your depth finder so that you understand its strengths and limitations.

Article Written By Candace Horgan

Candace Horgan has worked as a freelance journalist for more than 12 years. Her work has appeared in various print and online publications, including the "Denver Post" and "Mix." Horgan holds a Bachelor of Arts in English and history.

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