Can A Fish Finder Work Out Of Water?

The question of whether you can use a fish finder out of water is probably more common than you think. 

The simple answer is no. A fish finder will not work out of water. To be more precise, the transducer will not work out of the water; therefore the entire system will not work.

That’s not to say it won’t turn on. You can certainly turn it on. However, sonar waves need to travel through water – they do not travel through the air. 

Therefore, whatever reading you see on the screen, is meaningless.

Importantly, turning on a transducer while out of water is likely to damage your transducer via overheating.

Let’s look a little closer at the common questions. 

Can I test my transducer in a bucket? Why do fish finders work in water but not in the air? And Can I test my transducer out of water?

Hopefully, we can clear up a few misconceptions and worries.

Why do Fish Finders Work in Water but Not in the Air?

The word SONAR is an acronym for Sound Navigation And Ranging. A fish finder requires a device called a transducer which sends sound waves through water.

Think of a transducer as both a mouth and an ear. The mouth yells, projecting sound waves. 

Those sound waves bounce off objects under the water and return to the “ear”. I.E., send and receive.

The technology in your fish finder deciphers this sound wave information turning it into images on a screen.

Sonar requires the density of water to work effectively due to the length of sonar waves. 

If you turn on a transducer in the open air, the sound waves will disperse, instead of sending a directional ‘pulse.’

Also Read: How to Read a Fish Finder Screen

Can You Run a Transducer Out of the Water?

Yes, you can run a transducer out of the water, but it’s by no means advisable with the exception of ice fishing. For more information on this check out my post on “can a fish finder work through the ice?”

Secondly, there is no value in running and transducer out of the water as it won’t deliver the information you seek.

The only reason you might turn on a transducer out of the water, aside from ice fishing, is to assess if there is power getting to it quickly.

A transducer will work through ice reasonably well so long as there is a good seal between the base of the transducer and the ice.

Remember, sonar waves will not travel through the air, and images will be corrupted if there is any air between the transducer and the ice.

Therefore, when using a transducer on the ice, the ice should be clean, bubble-free, and completely sealed to the ice.

Obviously, there shouldn’t be an issue with a transducer overheating when it’s situated on the ice. Check out my article on how to know if your transducer is bad.

Can I Test my Transducer out of Water?

You may wish to see if there is power going to your transducer. When a transducer is powered up, you will be able to feel it or even hear it.

That’s all you will learn, however. 

You will not be able to test whether it’s sending and receiving or how well it is sending and receiving. To test a transducer properly, it must be placed in water.

Can You test a Transducer in a Bucket of Water?

There is little to no value in testing your transducer in a bucket of water as it is simply not deep enough.

A transducer will need at least a few feet of water to begin working correctly and giving appropriate, decipherable readings.

Should you have the luxury of a backyard swimming pool that’s 4 to 6 feet deep, you could certainly test a fish finder by rigging the transducer to a surfboard or the like.

You could even place objects on the pool floor or suspended somewhere in the water column to learn how such items are displayed on the screen.

Is it Harmful to Turn on a Fish Finder Out of the Water?

When I’m asked this question, my response is always the same – It should be avoided. 

Different manufacturers and units within the range of a particular brand will usually have advice about this, often found in the instructions.

Garmin, for example, suggests “A normal 500w or less transducer should not have any issues when running out of the water.”

However, they go on to say that 1kW models and larger may have the potential to overheat without the cooling effects of water.

If left on for extended periods without water, they could burn out or sustain damage from excessive heat.

The operative part io a transducer is piezoelectric crystal. By and large a fragile component, it’s surprising how much of a beating your transducer can take.

Heat, however, is not good for piezoelectric crystals, and overheating can cause fracturing and serious damage.Keep in mind CHIRP units are even more susceptible to heat damage.

At the very least, frequent moments of excessive heat, while not causing the sort of damage that will hinder performance, will shorten the working life of your transducer.

Ultimately, as running your transducer out of water is of no value, it should be avoided to ensure your transducer has a long working life at peak operational power.

If you wish to turn on your fish finder for whatever reason, be it a software upgrade or to learn something about modes, etc, make sure your transducer is isolated and not operational.

The only exception to this might be if you wish to see if power is going to the unit, in which case, you have enough time to assess the power connection without risking heat damage.

How Deep Does a Transducer Need to Be in the Water?

Transducers are mounted level to the bottom of the boat’s hull, usually on the transom of your boat. Essentially, they’re sitting just below the water’s surface.

To test your transducer’s basic readings, you’ll need about 4 feet of water. This will vary between brands and models, but 4 feet is a good rule of thumb.

This is testing basics only, such as depth and water temp, for example. 

For more revealing testing, you need to be out on the water, testing at various speeds and depths, as well as underwater structure and habitat.

Final Notes on Using Fish Finders Out of Water

There is little to no value in using a fish finder system out of the water except for ice fishing. 

And for ice anglers, a flasher (ice fishing sonar) is designed specifically for ice fishing, so better than a standard fish finder for ice applications.

The best you can achieve operating a fish finder out of water is an indication of power to the transducer. 

The worst that can happen is serious damage to your transducer and a shortened life span.

If you wish to play with the fish finder display while out of the water, simply disconnect the transducer, or ensure it’s not operational.

A good transducer working at peak performance is the key to a good fishfinder system. You can have all the interpretative functionality in the world on screen but it’ll go for naught if your transducer is functioning under duress.

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Sean Ward

Sean Ward

Hey there, my name is Sean – OnTrack Fishing is my site. I’m based in the UK yet I’ve been fortunate enough to catch bass in the States, barramundi in Australia, trout here at home and carp on the Danube delta. If I’m not fishing, or talking about fishing, then….I’m probably asleep.


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