First….one note for all foreigners who will read this: some parts of the text may not be fully understood by you. This is because it is a local dialect and local fishing waters that are relatively small for most of the world. In our waters (Croatia), the fishing regime (fishing rules) is very complicated and most anglers are still very traditional, so sonar is a novelty that is still slowly coming into use. Please keep that in mind.

It’s been too long since our last article, so we rolled up our sleeves and tried to write about something lately, very popular in our part of the world. It is, of course, a sonar (fish finder) as the title tells us. The authors of this text are Deeper Sonar “field testers” and our task is to test Deeper equipment in as many situations possible and based on that to form an opinion with the aim of improving the product and informing end users. In this task we will try to be as objective as possible.

What is sonar?

Let’s not bother you with unnecessary technical details that you can “google” yourself…. Sonar is an electronic device that allows you to “listen” through water. Yes, it is intentionally written “listen” and not „see“, because sonar emits sound waves through water and receives an echo that bounces off, so it “listens”. Complex algorithms are turning this echo into a picture on our screen. That is all “the wisdom”. Modern sonar was patented in the early 20th century, after the sinking of the Titanic, although the invention itself dates much earlier. So….this is a short history.


What is sonar for?

We are of course interested in fishing here. In the world of fishing sonar has been around for a very long time. The truth is that everything about sonar was intensified with the popularization of the Internet and foreign fishing competitions. We gained a better insight into these „magical“ electronic devices, and even wished to have something like that. Why would that be wrong? Nowadays, it is difficult to imagine any vessel at sea or a larger (navigable) river that doesn’t have some kind of device of this type. The information provided by sonar is essential, whether you want to navigate or sail at night, avoid some kind of underwater obstacle or simply find a fish. And that doesn’t bother anyone. The problem arises when you mount the sonar on a boat and when you appear on a “smaller” river or lake with such a boat. After the “traditional” type of fisherman sees someone with a “TV” on the boat, black thoughts start to travel through his head: „What kind of modern nonsense is that? Who needs it?“ A real fisherman catches fish with a willow rod, horsehair and a hook handmade from a bone. He doesn’t need such aid. This is a complete misinterpretation of situation. It is a modern age, fishing is also modernizing and it is necessary to move forward. However, it should always be in mind of every fisherman that the more knowledge we have and the greater our potential impact on nature is, the greater should be our responsibility too. That should be clear as a day. There are fewer and fewer fish, as well as free time for fishing, so we want to speed things up and this is where sonar emerges. We should also mention the fact that today, in search of fishing experiences, we travel farther than ever, discover new waters and here sonar simply allows us to adopt faster.


We do not want to enter into the morality of the whole story, because everything depends about an individual and his personality. Sonar should not be a reason for someone to empty certain water, although the danger of such a thing is very real, especially on our ponds and smaller rivers. The fact is that sonar is a device that finds fish. So…be smart.

Despite everything, progress is the natural course of things and it is not worth fighting against it. Who has understood, will understand, who has not… – may remain traditional.

With and without sonar, rules of acceptable and permitted in fishing must exist. Unfortunately, there are a lot of larger waters in Croatia where the use of boats is not allowed in order to “keep” the fishing stock, and the same waters are most often devastated and unused. Abroad, by contrast, there are many fish-filled waters where the use of boats and sonar is allowed. We seem to be doing something wrong. But let’s get back to the topic. Our next question:

Will you be a better fisherman if you use sonar?

Well…yes and no. If you make an effort to understand the data provided by such a device, your results will surely be better, there is no doubt. On the other hand, if you buy a sonar and think that you will immediately become a master of masters, without turning on your “processor”, you will be very disappointed. We are following a lot of fishing competitions and everyone on the boat has some sonar, and some competitors have a few units. All of these are just the most expensive and best devices currently on the market… but there is always only one winner. Simple as that.


Personally, we have been using a sonar more intensively over a year and we consider ourselves as beginners, but with every fishing trip we are trying to understand more and fish better. The information provided by the device is very important to understand the state of the water. During competitions (we want to put an emphasis here), especially when you are on some water for the first time, reading the water is half the battle. Sonar allows us to read water faster, because during competition time is a limiting and most often decisive factor. If you find yourself on a big lake, the benefits of sonar are even more pronounced. Personally, we do not sympathize with the term “fish finder” that people often use, because we consider sonar as a device that is much more than something that will only find us a fish. We primarily want to understand why that fish is on some spot and what the behaviour pattern is. Those information will help us catch more fish at a given moment and certain conditions. Because of this, temperature and depth of the water, location of the underwater structures, type of bottom, air pressure and exact time and position are much more important data for us. The possibilities of using GPS coordinates to memorize a specific point – fishing spot and to make bathymetric maps of the water are very helpful. In short, this is what we need from sonar and what we use in practice.



In the wide choice of ​​all kinds of devices that exist on the market today, we stumbled upon a company from Lithuania that produces, they say the only one, a Chirp device, which can be thrown from the shore or used on a boat. Why did that ball the size of a tennis ball and weigh about 100 grams (3,5oz) seem more special to us than other „toys“ on the market?


First of all, we don’t fish exclusively from a boat, so we planned to cover more situations with this device. In addition, the price of such a device is more acceptable than other “deck” versions of sonar offered on our market. Another, very important point is that Deeper is portable device that literally fits in your pocket, can be used on a boat, and can be easily used from the shore too. All you need is a rod and reel to cast it. The deeper does not need a special power supply, as it has its own rechargeable battery. You do not need a special monitor to view information – an average smartphone or tablet is enough to connect wirelessly via Wi-Fi signal. The data quality is, now we can say, quite decent for a 2D sonar.


We compared the data given by much more expensive units and Deeper at the same time and there were almost no differences. It is true that Deeper’s “noise” was a bit higher, but this is quite acceptable for this price range and does not affect the overall “picture” much. In other words, Deeper will serve you to improve your fishing. The application used by Deeper sonar is easy to understand and is “user friendly”. You really don’t need much to understand the basics, even if you’re a total beginner. Connecting Deeper and mobile device (mobile phone or tablet) is quick and easy. In most cases, you will have no problem breaking the connection between the probe and the device you are using as a display. There are currently four variants of Deeper sonar on the market, so you have Deeper Start – device intended for recreational users and those just entering the world of sonar, Deeper Pro – intended for more experienced users, Deeper Pro + – already a serious device with a built-in GPS locator and currently the best, Deeper Chirp +  – a sonar that uses Chirp technology for the most precise picture of everything below the water surface.


You can find everything about those devices on the Deeper website.  Deeper is trying to provide end users with the most detailed support possible. We must also mention that Deeper gives a 5 year warranty on the Chirp + device, which proves how serious they are and how much they trust their product. For Deeper the user is always in the first place, so they try to add more high-quality, useful and interesting add-ons to the basic package throughout the season – all for the same price. The example was Deeper Winter Bundle package, that, in addition to the Chirp + device, comtains a free thermos, neck scarf and night cover for your sonar. Also, from time to time, Deeper runs a prize game on social networks, where with a little luck you have the opportunity to win your Deeper Sonar, completely free of charge. Thank you deeper.


We promised to be objective, so it would be frivolous not to list the possible shortcomings we noticed using Deeper Sonar. The device of this price range is of course not a “holy cow” and cannot be measured with much more expensive devices that come with various functions, such as: side view, down view and 360 view, and are equipped with probes which are able to display the bottom in great detail. But we are pretty sure that in the near future Deeper engineers and developers will get around to it and that we will have all these capabilities in a 100 gram device.


The battery on the device is small, long-lasting and quickly rechargeable, but still during all-day use, say in an 8-hour boat competition, it is not enough. It would be great if a spare battery could be used, which is not possible for now. The battery on the smartphone also drains quickly, because the screen is constantly on, but we can get around this by using an external power source. To use a Deeper on a boat or kayak, you need a “flexible arm” over which the probe is mounted to be both fixed and “tied” to the boat or kayak and flexible – to float freely on the water and transmit a signal. In calm conditions, everything works perfectly, but when the waves are bigger or when the boat is in motion (when it is moving faster), the water splashes the antenna at the top of the probe and the signal is poor or lost, which can be quite irritating. As “field testers”, we are obliged to warn the manufacturer about this issue and suggest that it would be great to have an extension, or antenna that could be additionally mounted on Deeper to prevent this problem. For a normal use, Deeper users should also have a functional phone/tablet holder on a boat or kayak. It would be convenient to have a waterproof phone or case, because otherwise you will be limited on days without rain and very disappointed when the water splashes your mobile phone that is not waterproof. In short, these are our observations concerning Deeper boat usage.


When Deeper used from the shore, the disadvantages are much smaller, in fact, there are almost none. The signal is good and the range is the one specified in the device specifications. We didn’t measure a length, of course, but in practice we threw the device as far as we could and we had readings on a smart phone. That should be pretty credible. It is our opinion that the best application of Deeper sonar could be in carp fishing. Don’t get us wrong, nothing will and can’t replace quality position marking (after all, it is science and mastery), but Deeper can help a lot when you are scanning certain spot.


We got more ideas related to the use of Deeper in stationary fishing, for example, mounting the device on small electric boats on remote control for feeding or stretching the system (of course where they are allowed). The possibilities are really countless, you just need to involve your imagination. In lure fishing from the shore, to probe closer positions, it is enough to throw a Deeper with your hand. It is very precise and effective, both on calm and slow flowing waters. We didn’t use Deeper in salt water from the boat, while there were no problems using it from the shore.

This is a short story about a Deeper Sonar, a device that is, despite its shortcomings, a real small machine and tool that has nothing to be ashamed of among the big and much more expensive brothers.

Thanks for reading and stay HEALTHY .

Text and photo:

Goran Ovčar Mladi & Robert Baričević

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