How Does A Fish Finder Work? And How To Read Them?

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cover image of how do fish finders work

Fishing is a sport or a hobby or whatever you want to call it, it’s different for each and every individual, but it sure is a practice that involves a lot of fun and enjoyment.

But this practice will turn into trouble and hectic if you are in muddy waters, yes people, you should be prepared for every other situation. Because sometimes the clearest of waters can get dusky and hard to see through. But how will that affect your fishing spree?

You see, when you fish in deep waters, especially, you go through the water with the naked eye to see the kind and the number of catches that you may find in that water body.

But if the water is not transparent enough, then you won’t be able to see anything, and that can result in a failed fishing trip. But there is a way that won’t let your fishing adventure to fail and that will be because a device called the fish finder.

What Is A Fish Finder?

A fish finder is a device used by many kinds of people but especially the fishermen to find the potential catch in the water body. This device works on the technology called SONAR, which means (sounds navigation and ranging). This device holds it’s significance today among folks who professionally catch fishes or people who pursue fishing as a hobby.

One of the many components of a fish finder is its’s screen, the LCD screen on which the fishes or the potential catch is displayed. You might think that a fish finder is a technology used in today’s time only, but that is not the case. A fish finder is a device that was used since the ’90s and has been in a state of a constant upgrade since that time.

A fishfinder with different fishing rods

In the olden times, there used to be big setups of proper monitors used, that’s why these devices were used in big ships or huge boats, they were not used in small-sized ships that couldn’t handle the weight. But now, as we moved on to so many upgrades, a fish finder is as small as a GPS or an LCD screen.

Today, every other person who thinks about searching the water bodies for the right amount of catch are in search of great fish finders, but before even getting to work on these fish finders and start to search them, you need to understand the nature of these devices and know all about it so that you can find the best one.

Different Types of Fish Finders

Since the times have changed, fish finders have become something that is important for each and every individual who decides to step in the water for a catch.

Previously there were only a few models available that sold fish finders but now the times have changed and there are more updated versions, all are available depending on what you need, and in this section, we are going to discuss the different types of fish finder so that you may choose the most suitable for you.

When planning on buying a fish finder, you need to know the types of fish finder’s available and all about them, there are basically three types of fish finders available, and they are as follows:

  • The standard 2D fish finder.
  • The fish finder with down scan and,
  • The side-scan fish finder.

Before moving on to a more detailed view about these types of fish finders, keep in mind that each and every fish finder has its own advantages and disadvantages, so you have to keep your mind open to choose the most suitable one for you.

Did you know some companies merge the qualities of two fish finders to make something that goes along with a different kind of need? That is why you need to keep your needs in mind when choosing something for these blue sheets.

The 2D Fish Finders

These 2D fish finders will remind you of something from the olden times, well, they sure are pretty standard and easy to understand and use, let’s get into the dynamics to learn more about them.

They have a black and white color display, and with a pretty standard scrolling system, you can see pretty much everything beneath the water surface, the soil, the reefs, and also the fishes are available at that time.

A 2D Fish Finder Interface

Yes, identifying fishes from all the other things can be pretty tricky in this kind of fish finder, but if you are someone who has a proper understanding of this kind of digital device, then it won’t be much of a problem for you.

The fishes in this 2D device are mostly identified through their bladder, which is displayed by a dot or a dash; it’s easier for people having a keen knowledge about this kind of device.

But if you want to use a 2D fish finder and if you have no experience of how to use it, they keep this in mind; you would 100% need some guidance or training with this kind of monitor.

The Down Scan Fish Finder

If you are not someone who is a professional, then you might think of fishing in shallow waters before going big, you might even not want to buy material that is way too expensive, and that is totally understandable, and that is where a down scan finder comes in.

This is perfect for shallow waters because it gives you a downright view of the water body, it is relatively cheaper than the other kind of fish finders, and it sure does work smoothly.

A down scan fishfinder image

The fish that are displayed are quite clear; any sudden movement of the fishes makes it easier for the fisher to catch them because the sensor goes off in a loud motion.

The hard rocky surface is not visibly seen in the finder, but the fishes are quite easily visible if you are keen on the shape of the kind of fish that you are planning on catching.

One of the downsides of using this fish finder is that it can’t navigate with a larger space, you have to confine your specific area, and if you are unable to find a catch there them, you might want to move on to another piece of that water body.

The Side Scan Fish Finder

If you are a professional fisher, or if you are someone who pursues fishing as an expensive hobby, then we are confident that this kind of fish finder will go perfectly for you.

A side scan imaging screenshot

Looking at the dynamics of this fish finder, you will see that this is the most photorealistic that any fish finder can get; it covers a small area around your boat, but it does cover it very efficiently and gives you a prominent picture of what catch is lurking underwater.

It ranges from a 1-meter range to a good 30 meter of range covering every and any fish that it can find in between.

This scanner is genuinely perfect for the widespread lakes and the deepwater rivers, someone who takes fishing as luxury will truly love what it has for them, and we are emphasizing the luxury part so much because this will cost you a lot of bucks.

The Basics Of A Fish Finder

For getting into the next part regarding the fish finder, you need to understand the basics or the composition of a fish finder in the first place. The fish finder is composed of two main parts; one is the head unit, which is also called the monitor or the LCD, and the second one is the sensor.

Now, for your better understanding of this situation, the monitor remains on top, with you, to look on, and the sensor goes underwater so that it can see or sense the movement in the water body.

Image showing different features of a fish finding device

Nowadays as we earlier mentioned that companies are getting more advanced and they are composing fish finders with many other benefits too, keeping in mind that, these companies are making more advanced models which are comprised of many features having more than just the sensor and the monitor, but we are looking for the basics here.

The side view and the bottom view of fish finders are the ones who use motion sensor technology to detect the fishes underwater.

In the following parts, we will educate you about the components of a standard fish finder; this way, it will be easier for you to choose what kind of fish fonder you are planning on buying.

– The Transducer:

Let’s explain to you the easy way, you see, the monitor is the eyes of your gadget, and the transducer is the ears of your device. The transducer performs all the actual work of the fish finder that happens underwater; it consists of the primary sensor that is responsible for detecting any moving matter (fish) under the surface.

The sensor present in the transducer then sends signals to the monitor of whatever it perceives on the screen.

More info:

There are different kinds and types of transducers available, but each and every sort of transducer consists of a sensor that vibrates or makes a ping sound when coming across any frequency. The sending and receiving of signals are able because of a technology called a (sonar) system, which means sound navigation and ranging.

A transducer image

As we earlier told about the different kinds of transducers, they are chosen according to the sort of frequency that you need underwater, for example, a 2D fish finder, which is also a standard fish finder uses leas frequency as compared to the other fishfinder.

– GPS And Chart Plotters:

Many of the fish finders have amazing GPS built in them, and that is a fantastic feature because that helps us to navigate our boat or whatever thing we are on according to the fishes available.

This GPS tells precisely where to move, at which angel, and through which way, sounds impressive, right? Well, there is one more feature that may astound you; this GPS is also responsible for making a sea map for your fishing.

A GPS Chartplotters image

For example, at a specific spot, you managed to have a great catch, and now you are planning on going back to that particular place, so you would want to plot it on the navigation system, this way you will be able to go to that place again no matter how far it is because you would have your GPS tracking with you.

But yes, there is a downside, and that is this GPS only works terrific when you have a high-quality fish finder.

– The Networking Of Fish Finders:

You might not need this feature if you are not a professional fisherman, and that is because networking is done when there is more than one fish finder on your boat. But why would you have more than one fish finder on your boat?

You see, more than one fish finder helps you in covering a more extensive range, you might want to put three or four fish finders in different corners of your boat, this is only possible if you have ample space.

More Reading: How Should You Pass A Fishing Boat?

But having more than one finder is hectic in itself; you would need a proper navigation system when coming to these number of finders, and that is because you can’t keep a check on each one of them by staying at the same place.

A garmin finding device while fishing

By building a network, you will be creating a way by which you can monitor all the fish finders at the same time by being in one place, the functionality and the screen of all the fish finders will be shared with you.

Always remember that not all fish finders are the same, so different fish finders have a different way from which they network, and you would have to follow or make sure that you have the right way of networking.

– The Display Of The Fish Finder:

The display or whatever we would like to call it, a monitor or an LCD is the head unit of the fish finder, it shows us what is beneath the water on the screen that is displayed in front of us.

The quality of the display varies in the quality of the finders, some expensive fish finders have displays that are high in class, and some are not.

A raymarine device for finding fishes under water

What they display is another factor to consider too, sometimes all they display are sensor lines which tell you when the frequency goes up and down, and sometimes they give us a proper pictorial view depends on what kind of fish finder you are buying.

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How To Read A Fish Finder Display Properly

Talking about fish finder displays, you have to make sure that you see the right things on the monitor, don’t expect a pictorial view on the monitor. Sometimes there can be lines, or sometimes there can be just waves, you need to understand how to read the display properly.

But don’t you worry because we are going to help you through that whole process and you are going to make it out just fine. There are four kinds of displays that you need to understand are 2D sonar, Side imaging, down imaging and, chirp.

1- 2D Sonar:

This kind of sensor uses a cone-like beam to see what is beneath the blue covers. The fish finder here is like a metal detector that is used to detect a metallic substance underwater, here these beams detect fishes instead of metallic substances.

The sensor keeps making ticking or pinging sounds and then interprets those sound wave on to your screen, the return’s patterns move from right to leave, which means the image forming in the right are the new ones and on the left are the old ones. A cone-like arch will appear when a fish goes near the sensor, and it will indicate to you about it.

Most of the time the screen can be deceiving, and you might see blobs or something on the screen, you need to understand these blobs to understand what is going on, let’s see what appear as what on the screen.

A 2D sonar image with stats

Big groups of fish would look like big blobs on the screen, but don’t be too happy because they can also be big bushes of reefs or something.

The solid ground will be seen like a bright yellow or something of bright color; a muddy bottom will have an orange color.

Now, fish depends on what kind of fish are you looking to catch, you might keep in mind the shape of the fish you are looking at, the shape may appear like a long, flat or circular shape, or will be like a shadowy figure, and it will be easier for you identify what kind of fish are you looking at.

Some people fall into a very controversial argument of whether you should use a 2D sonar or not, this is because of the display, the kind of display, I’m cone-like shapes. Some anglers don’t prefer to use this kind of display, and they have their reasons because of that.

They say that they prefer a more pictorial view rather than a cone-like structure because that is way more confusing.

2- Down Imaging Display:

Some people are very skeptical about down imaging display because the most asked question is what you see from the down imaging sonar, and the answer lies in the name itself.

The view is seen from above, so everything is seen as we see it from above, e.g., a mass number of fish would look like small circles from above when the down imaging display starts to work.

But yes, they do look much smaller as compared to the 2D sonar, and this is because this is the downward display, so even masses will look small on the screen.

A down imaging display from a sonar

The bottom, however, will look at the same, like a bright yellow color or a bright orange color on display. However, if you see a thick color or something, then it’s undoubtedly a hump of must or dust on the ground.

3- Side Imaging Display:

Side imaging displays can be a little complicated to watch, but they are more bountiful rather than any other display. Side imaging displays are tough to interpret because of the fact that the screen is shown from the side.

The beam of light comes from the side, and that is why they show a little blur, the fish will look like they have better and brighter returns.

4- Chirp:

The chirp range of display is a better and smarter approach because it uses a single frequency and just goes up and down; the frequency line goes up or down, telling what is below the boat.

This kind of display is best for people who have a large space or have more than one fish finder, and this is because of the pulse-like motion that appears on the screen, and that is easier because once you get ahold of what thing is to find on what frequency and what fish has what frequency them it would be easier for you to understand everything according to the frequency numbers.

Understanding the CHIRP

Now that you have a good amount of information on the fish finder display them, we think that you are ready to move on to the next level, and that is how to install or configure a fish display properly.

How To Install And Configure A Fish Finder Properly

No matter how great is your fish finder, if you don’t know how to set it up to properly then you won’t be able to make the most out of the device but don’t you worry when you have us because we are going to make sure that everything goes as planned.

In these steps below, we are going to tell you all about how you can install and configure your fishfinder properly.

But first, you need to make sure that you have everything that you will possibly need to install this fish finder because let us be real here, we don’t want to hire a handyman to help with these chores if you can do it yourself.

Make sure that you have the right equipment and tools that you would need for this fitting process.

A raymarine fish finding gadget

We are sure that you would be having more than half of the tools at your house, but don’t worry if you don’t have it because we are certain that your local handyman or hardware store will for sure have the tools you need.

The tools you would be needed are as follows:

  • A fish wire
  • Phillips head screwdriver
  • Wire stripper
  • Wire crimper
  • Fishing rods
  • 3M 5200 adhesive.
  • Adhesive-lined heat shrink tubing.
  • Cable ties
  • Mounting hardware.
  • Silicon sealant.
  • Clamshell fitting
  • Terminal connectors.
  • Crimped barrel connectors (this is optional, you might be needing it and maybe you won’t at all)

These are A to Z, all the things you would need for this whole process, we would suggest you make sure that you have all of these or else you won’t be able to make the best out of your fitting process.

Now let’s move on to the real deal and that is how do you install a fish finder?

1 – Register Your Fish Finder

After all, our fish finder is a device, and like any other modern tech device it has its own updates and the latest news regarding it and like any other device we need to get it registered by setting up our email to the manufacturer, this way they would know the know about of the finder, and we can get it fixed easily if we came across any problem.

YAK FishFinder Image

This will be an easier process because then you won’t need to take your finder anywhere, the solution will be just a call away from you. Whenever there will be some new updates about your fish finder, then you will get updated instantly.

2 – Now Update Your Fish Finder Software

As we already told you that a fish finder is like any other mechanical device. Hence, it’s certain that you would need proper updates from time to time for your finder, but one thing that you need to do after registering your finder is that whenever you take it out, you need to make sure that it is updated to it’s the latest version.

Updating a humminbird

If your finder is not updated to the real version, then it will cause problems whenever you start to operate it, and we know that you wouldn’t want a finder that is foul and keep getting you in trouble.

One more thing that is related to setting up and updates of the fish finder is that you need to make sure that your fish finder has enough memory to take a good amount of pictures. Some fish finders have built-in memories, and some require an SD card, they have specific slots for the SD card, and you may insert the amount of GB you prefer.

3 – Find The Right Place For Setting Up

Finding the right spot for your fish finder can be a really tricky topic, and that is because most of the time, people don’t have enough knowledge about what they should do bit don’t you worry a bit because we are going to tell you all about setting up your fishfinder.

First of all, make sure that you place the monitor of your fish finder is a placed right where it should be, at the helm of your boat, at a place where you’d normally fish, and the higher ground where you can keep an eye on it.

Finding the best place to set the fish finder device

But make sure that you don’t put the monitor at a much higher ground, it should be somewhere between the height of your shoulders to your hands, this is not much low and not too high, at this angle, it will be easier for you to keep an eye on the fishes lurking beneath.

Keeping it at the right place is very important, this is because you need to focus on driving while keeping watch on the monitor.

4 – Find The Power Source

This kind of gadget does need a proper power supply attached to it every time; you would need a battery or a power generator to keep up with the power need, we would suggest using a battery because it is a safer option rather than a generator.

A Fish Finder with a Battery

Batteries are safe because they don’t need electrical wiring, and they are much easier to maintain, but keep in mind that if you are thinking of using a battery, then you need to make sure that you have all the wires attached and all the holes drilled properly.

You need to set all this up before going on your fishing spree; make sure that all the wires you have attached are cut short because if they will be elongated and spread all over the boat, then it will be dangerous.

5 – Drilling For The Wires

Most of the time, the boat you buy already has the holes drilled because there might have been a fish finder installed in that boat earlier, too, but if there is not them, don’t worry because we are going to help you through it.

You have to drill and mount the number of holes you need to install your finder, make very sure that you use a high power drill, leaving no splinters or anything behind that might harm you.

6 – Add Sealant

This sealant is for the holes you have just drilled, sealing these holes are very important because you don’t want to lose wires that will result in more problems such as an unfitted fish finder that may fall down in the water.

The sealant should be applied in a decent amount around the holes, not too much, and not too least; we will also suggest you fit some but and bolts around the wholes after applying the sealant; this will ensure strength.

Also, the sealant will make sure that no water enters your boat whatsoever.

7 – Running The Power

Now we need to connect everything together, that is the power lines, the power should be connected to the fish finder and the battery, you need to make sure that the wires are connected all together so that everything can move in a smooth operation.

In this step, you need to inspect the length of the wires and see where it needs trimming, make sure that you insert the cables according to the colors and the wire ways.

We would also suggest you go through the manual to get a helping hand with the installation.

8 – Setting Up Wires For The Transducer

This is one of the most critical steps, and that is setting up the wire for the transducer, you see, the transducer is a device that goes into the deepest part of the boat, the SONAR technology tells you the whereabouts of the fishes.

A image stating how to install a fish finder accurately

You need to drill and mount the wires in the exact place for the transducer but before that keep some points in your head, don’t mix the device’s wires up with the engine wires, and make sure you apply sealant wherever is it mounted.

The transducer should be accurately and adequately attracted to the boat because of the heavy water pressure that may knock it down, and you won’t certainly want that.

9 – Installation Of The Transducer

The transducer mostly goes beneath your boat, and that is the most crucial part of your most.

Did you know? That if you don’t apply a good amount of sealant around the mounts where the transducers will be placed, then there might be a risk of water entering your boat, and knocking it down, sounds horrible right?

Transducer Stats image

That’s why we would be extra sure about the fact that our transducer is in the right place, the wires at the property attached, and the holes are correctly sealed with sealant.

10 – Setting Up

Now, these are the last steps of setting up and making sure that everything is working smoothly. Go on the boat, check all the fittings, and check all the wires and if they are correctly installed.

Turn on the power of the battery and make extra sure that everything is working okay. If something is not working fine, then all you need to do is recheck the connections with the wires.

Image of a fish finder attached to a boat

But this is not the end of it, double-check all the openings ( the mount holes and wire holes), make sure they are correctly sealed and shit so that no water enters your boat.

Make sure you are getting a good supply of power and then check the transducer because that is the device that will help you see beneath water. If everything is working fine, everything is intact and shut, and is getting a good deal of power; then you are finally good to go!

Tips To Remember When Using A Fish Finder

You can’t be perfect at every single thing, and we do accept that fish finders are a tricky subject. But down here are some smart tips and tricks that will help you mastering the device and catching more fishes.

  1. We use a fish finder to catch more fishes, right? We have a tip for you regarding that, whenever casting, make sure you cast when the fishes are feeding over something. Feeding fishes appear in a different form; they seem like thick round schools of fishes.
  2. Always use the zoom feature. Many of the people underestimate this feature but trust us these features will appear to be a great help because sometimes fish finders can be recovering, you might take a group of fish as one large fish, zooming in will give you clarity about it.
  3. Always keep a keen eye on the temperature according to the kind of fish you are looking for, for example, maybe that fish likes to swim around in a 70-degree range, but you are searching for it in 50 degrees.
  4. Sensitivity adjustment. This is something that highly depends on how experienced you are; if you are someone who can differentiate between algae and schools of fish in high sensitivity, then you are good to go, but if you are facing a hard time, then we would suggest turning the sensitivity down.

No matter how much you know something about a particular subject, you still have queries about it, and we know that you must also have some questions revolving in your mind, but we will surely resolve them.

Final Verdict:

Fishfinders are devices that are used by fishermen or archers to locate fishes beneath the water surface; they use a sound and radiation technology called SONAR.

These devices are beneficial with fishing of any kind because they give a supporting hand in locating fishes of a specific type.

There are many pieces of this device, but if you have the right amount of knowledge about how to install and maintain everything, then this device is undoubtedly going to be the best decision of your life.

This read here will be a great help for beginners or even experts who would like to know all there is about fish finders.

Frequently Asked Questions

#1 – How deep do fish finders work?

Fish finders can work as deep as you want them to work; all you need to do is set frequencies accordingly. The deeper the waters, the lower the frequencies, for example, 200-800 kHz for water depths that range up to 200 and 80-50 kHz for waters that are in lesser depth.

#2 – Why do fish show as arches on SONAR?

This is because of the beam angle that is exerted by the transducer, as the fishes or schools of fishes enter and exit the beam, the cones are thus formed.

#3 – Is a Fish Finder A Depth finder?

There is a significant difference between a fish finder and a depth finder, but a fish finder also displays the depth of the water body you are fishing in. So yes, you may use this device as two devices in one.

#4 – Do fish finders come with transducers?

Yes, most of the time, fish finders do come with transducers because the trolling device of your fish finder should be compatible with your transducer, and buying both of them separately can result in foul results or worse, no connectivity at all.

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  • Since 2009 I've been writing on different media portals about fishing. Here on this website, it's time to share those experiences I've witnessed in my entire life so far. Let me help you get the best stuff you need while fishing.

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