How Fish Finders Work

Some people may think that fishing isn’t really a sport per se and that landing that monster fish is more a matter of luck than skill.  Nothing could be farther from the truth!  Smart anglers know that possessing the right equipment is a huge part of a proper strategy, and having a good marine electronics installation with a fish finder on your boat is a key component to help you land that monster fish!

marine electronics

Fish finders are advanced pieces of technology that actually allow you to “see” what is going on underwater.  But how do they work?

Fish finders are essentially sonar units.  Sonar is the use of sound waves throughout the water medium.  There are two major components to a fish finder system: the transducer and the control unit.

Control Unit

The control unit houses all of the electronics needed for the system to work properly.  This is where the main screen for the user is found, and it is commonly mounted to the boat where the steering controls are located.  It controls and manages the electrical signals needed to detect an object.


The transducer is the component of a fish finder that is actually submerged in the water.  Electrical impulses from the control unit are sent to the transducer where they are then converted to sound waves.  The waves then propagate through the water and, as they strike an object, are bounced back to the transducer.  The signal is then processed by the control unit, and the results are shown on the screen.

By interpreting the strength and frequency of the signal, the control unit can determine the size and the shape of an object in addition to identifying how far away (or how deep below the water surface) it is.

Proper Installation

Part of a properly functioning fish finder system is to make sure it is properly installed.  From an electrical standpoint, some of the cheaper units can have the wiring adapted to run off a 12VDC outlet, but the best way to ensure proper operation is to have it professionally installed.  It’s also important to have the transducer mounted in the right place relative to the water level so that the sound waves function as they should.

Companies such as Imagine Marine offer marine electronics installation services that will keep the system functioning properly, so you don’t lose track of that record fish!

marine electronics installation

Which one is right for you?

Finding the right unit for you is really a matter of analyzing your needs and overall plans for use.  Are you just a weekend warrior that likes to throw a line in every now and then?  Or, are you an expert (such as a tournament angler or charter captain) that needs to have the advanced technology that higher-end units offer?

Technology has advanced over time to where even the lesser-expensive units (some even under $100) have excellent features.  Color screens and sound alerts to let the user know when it has detected a fish are not uncommon in these lower-level units.

On the other end of the spectrum, there are units that can cost several thousand dollars that have advanced features such as having extensive GPS navigation capability, the ability to mark location points, and high-end screens with relatively large sizes, resolutions, and color palettes.

Fish finders are incredible pieces of technology that allow even the novice angler to land that big one.  Once you use one, you may never fish again without it.