How to Read a Lowrance Fishfinder

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Lowrance fishfinders provide fishermen, pleasure boaters and anyone else with an interest in learning more about what is beneath their boat the ability to do so. In some cases, having a fishfinder is a necessity, since they can help boaters avoid stumps, rocks and other objects that could damage their boats. But many people use Lowrance fishfinders for the sole purpose of finding fish. They want to know how deep the water is, what the bottom looks like and what kind of vegetation or other objects are on the bottom. The following will teach you how to read a Lowrance fishfinder so you can identify those features.

Press the power button on the front of the fishfinder to turn the unit on. Make sure the fish alarm feature is turned off, and that the fishfinder is in the automatic mode.

Look at the entire screen to get a handle on what your Lowrance fishfinder will show you. Focus first on the digital readings that appear on the screen. One of them is the depth of the water, measured in feet. Other possibilities include the water temperature and the speed at which your boat is moving.

Take a look at the bottom area of the screen. There will be a line that extends from one side of it to the other. This line represents the bottom of the lake, reservoir, or river on which you are boating. You can tell a certain amount about the bottom by studying that line. If the bottom is made up of hard material, like rocks, the line will be thick and dark. Conversely, a line that is thin and light-colored represents a soft bottom. A flat line means the lake bottom is flat, while inclines and declines in the line represent an uneven bottom. As the line angles downward, for example, the number on the digital depth reading will become correspondingly larger.

Study the objects just above the line. Doing so will give you an idea of what objects are on the bottom. Whereas trees or timber growing on the bottom will show up as vertical lines on the screen of the Lowrance fishfinder, aquatic vegetation will appear as thicker, more pronounced icons.

Look for fish in the water column between the line on the bottom of the screen and the top of the screen. Icons that appears as arches or as fish represent fish. The size of the icon depends on the size of the fish below. A larger icon represents a larger fish, while a smaller icon represents a smaller fish. Pay particular attention to where in the water column the fish are located. Are they right on the bottom? Just above timber or vegetation?


  • Place the transducer, which transmits signals from the water to your fishfinder, as near to the fishfinder as possible. If the transducer is at the back of the boat and the fishfinder is at the front, the view you see on the fishfinder is the area you have just passed.
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