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Can You Turn on a Fish Finder Out of Water?

Last Updated on July 26, 2022 by Donnell Henderson

When it comes to the question of whether or not you can use your fish finder while out on a boat in open air, there’s only one answer: no.

The simple reason is that sonar waves need water — they don’t go through the air as we do here at home, so whatever reading might appear on the screen would be meaningless if taken literally (and therefore void). Significantly, it directly influences the performance of your transducer and, later on, the fish finder.

How Do Fish Finders Work?

Modern fish finders have made the sport of angling much easier. Whether you’re ice fishing, saltwater fishing, or just going downriver in a bass boat, they help immeasurably with your hunt for that big one. But unfortunately, these devices’ work can be challenging to understand without knowing about sonar technology.

The first step to understanding how fish finders work is knowing a little about sonar technology. This can help you better read the device and gain awareness of what’s happening inside your boat or bass head when using one of these instruments.

The fish finder navigates through the water with sonar technology. It works by sending sound waves into the depths, and when something reflects these signals at us, they provide information about its depth. It explains the results about both distance away from us and what type of structure it might be composed of – whether insectile life-forms like rocks beneath deep-sea foam; or coral reefs bustling with colorful communities. You’ll be able to spot fishing spots and any aquatic life around, such as vegetation and shipwrecks.

The transducer sends vibrations into the water to measure everything below your boat. These signals return and then are interpreted by a processor, which displays them on screen so that you know what’s going on under there.

This explains that the transducer has the primary function when exposed to liquids. Hence, switching it on in the air will give you no essential information and just made-up readings while damaging the insides.

Why Should We Refrain From Turning on a Transducer When Out of Water?

can you turn on a fish finder out of water

You can always turn on a fish founder out of the water, but as said always, the less transducer is exposed the better and it should be avoided.

As we know, the transducer is a fragile component that can take some beating and not a lot. For example, 500w or fewer models could run out of water if used correctly, but 1kW units may overheat without the cooling effects in swimming pools with salt water.

Even though heat is not suitable for piezoelectric crystals, overheating can cause fracturing or severe damage to CHIRP units — even more so than regular transducers because they’re explicitly used in water environments where there’s lots of motion involved, such as sonar mapping ships’ decks and on other sites.

The only exception might be if you want power cycling through your fish finder while checking modes, but even then, it would just take one quick blast with some compressed air before returning into its protective housing again. So to keep your fish finders in good health for a long time, it’s advised to refrain from turning it on out of water with a trolling motor.

Can You Test a Fish Finder Out of Water?

So what if you’ve read our fish finder reviews and picked out one for yourself and you want to test it out?

It would be best if you first submerged it in water to test your depth finder’s ability. However, if this is not possible or desirable for some reason (e.g., there isn’t any nearby), running it out of the water will give an inaccurate reading that makes no sense — such as 1200 ft when only 10 inches deep at home.

This happens because transducers send and receive sound waves like they were underwater but pick up random noise when installed, which our processors cannot interpret correctly.

However, you can test a fish finder at home. It’s pretty easy to do. All you need is a bucket of water and a willing fish. Lower the fish into the bucket and then turn on the fish finder. If everything is working correctly, you should be able to see the fish swimming around on the screen. Of course, this isn’t the most accurate way to test a depth finder, but it will give you a general idea of how it works. So go ahead and give it a try!

Furthermore, this means you can turn your fishfinder on out of the water, but it’s no use. Instead, it harms your transducer and will cost you later.

Is Mounting Transducers in the Boat Hull a Good Idea?

Arguably, the most integral part of a fishing boat is the transducer, the head unit. This disk-shaped sonar sends and receives sound waves that allow anglers to find fish under the water. Most transducers are mounted on the hull outside, but some anglers wonder if it’s possible to mount them on the inside.

While it might seem like a good idea to keep the transducer out of harm’s way, this approach has a few potential problems. First, the sound waves emitted by the transducer need to be able to penetrate the hull to reach the water. This cannot be easy to achieve and may result in reduced performance. In addition, mounting the transducer on the inside of the hull can make it more difficult to install and wire correctly. For these reasons, most experts recommend against mounting transducers inside boat hulls.


There are just no two ways about this discussion, and a fish finder doesn’t work if it isn’t in the water. You might be able to get some preliminary power readings while it’s out of the drink, but that’s about the long and short of it. Not to mention, if you’re not careful, you could do some real damage to your transducer, and nobody wants that, even if it’s a low-end $200 fish finder.

So if you’re itching to play around with your fish finder display, just disconnect the transducer first. That way, you won’t be risking any severe damage. Because at the end of the day, a sound transducer is a key to a good fish finder system. All the interpretive functionality in the world won’t do you good if your transducer isn’t up to snuff.

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