There’s an old saying that goes, “90% of the fish are in 10% of the water”. The question is, where specifically is this 10%?
We genuinely believe that there isn’t any piece of gear that’s quite impactful more than a fish finder. With a good one, you can ride down a bank and see which docks have fish under them while simultaneously showing all the bottom structures you never imagined were there.
However, the thing is, it may be a daunting task to interpret all the technical stuff written on each product. Hence, we’re going to explain the essential specs of a fish finder that you should check before making the purchase.
Now let’s dive in more detail to learn how to choose a fish finder that will suit you in every possible way.
Table of Contents
Before we kick-off, you should know that the transducer is the director of the chief process by which a fish finder operates. Basically, it broadcasts waves that spread into the water until they hit an object and bounce back to the transducer, which allows it to interpret what’s happening in the underwater world below.
To help you understand what you’re looking for, there are two main things you should pay attention to in a transducer:
Frequency and Cone Angle
The cone angle is what describes the width of the beams emitted from the transducer. The broader it is, the more area covered under the water, but at the expense of the sensitivity. While transducers can come with cone angles that range from 9 to 60 degrees, most of the units you’ll encounter have beam angles that fall between 16 and 20 degrees.
As for the frequency, transducers usually come with 800, 455, 200, 83, or 50 kHz beams. High-frequency waves may provide the crispiest images, but lower ones have deeper penetration levels. That’s why deep-water anglers prefer lower frequencies as they can detect bottom dwellers at depths that exceed 1000 feet.
However, you don’t have to be limited to a single frequency thanks to the presence of dual-beam transducers. These sonars let you cover a greater area using a low-frequency beam while still having highly detailed images with incredible structure separation.
The second thing you should consider is where you’re going to mount your transducer. Generally, you have three options to choose from according to the type of vessel you use. The most common one is the transom-mount transducer, given that it’s the cheapest and easiest to install.
Fishermen with bigger boats usually resort to trolling motor mounts or thru-hull transducers. These may be more reliable than transom-mount ones, but unfortunately, they require drilling holes in your vessel or buying a separate adapter.
All in all, you should pay attention to the way your unit is installed to your boat as incorrect mounting can bring down the whole device’s performance.
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2. CHIRP vs. Traditional Sonar
Traditional sonars work primarily by sending one single frequency at a time, and hence, their returns may not be sufficiently detailed. On the contrary, CHIRP, which stands for Compressed High-intensity Radiated Pulse, sprays a bunch of frequencies, ranging from high to low, simultaneously.
By covering a wide range of frequencies, the subtle differences in the returning signals can be pointed, awarding you with high-definition images with magnificent separation between fish and objects.
Since every bit of extra precision matters, opt for CHIRP sonars as they produce more accurate and sharp details of fish, structures, and the bottom.
3. Down vs. Side Imaging
Honestly, this may be the most frequently asked question, but no one can answer it except for the angler himself. Depending on the type of water you’re fishing in and the amount of money you’re willing to pay, you can make this decision.
Down-imaging fish finders are more suitable if you’re trying to find fish in the vertical rather than the horizontal plane. Also, their ability to produce quality images even when you’re moving at high speed is a point in their favor since deep waters will demand that you troll with higher speed.
The problem is, with such focus downwards, it’s easy to miss any action happening to the sides. You may be able to know that there is a good catch 20 feet below you, but you won’t know on which side exactly you should work your lure.
On the other hand, opt for side-scan sonars if you usually fish in shallow water where your prime concern would be to cover more water to the sides. An average side-imaging fish finder will scan around 100 feet to each side of the boat.
Nevertheless, to get a feature like a down scan, you’ll have to ante up a lot of money as they’re more on the high-end of the price scale. Moreover, you won’t be able to speed up your vessel since they operate better at a lower speed.
If you’re the type who likes to leave his options open, manufacturers’ have taken your problem in mind and designed fish finders that hold both privileges. Features like StructureScan from Lowrance and SwitchFire from Humminbird are capable of collecting bottom data together with the data from both sides of the boat concurrently.
4. Power Rating
Broadly speaking, the more wattage you have, the faster your unit will display its returns of much deeper surfaces.
Since you don’t want to pay more for a fish finder that operates on loads of wattage that exceed your needs, determine the amount of power you want based on the water depth. For example, 100 watts are enough to reach a maximum depth of 400 feet, while 1000 watts can bring readings from up to 2500 feet.
Now, if you do most of your fishing in shallow creeks and bays, a peak to peak power of 200 watts should suffice. Yet, deep lakes and oceans require units that operate at 1000 watts or more. Finally, if you can’t make up your mind, aim for 500 watts of power as a happy medium.
5. Screen Size and Resolution
Imagine choosing a unit that’s equipped with the best technology and can produce the sharpest photographic images, then squeezing them in a tiny screen where you can’t really identify any details. Surely, that’d be a total waste of money.
Fish finders come in sizes from 3.5 inches all the way up to 12 inches. Unfortunately, a screen’s size plays a fundamental role in deciding the price of the unit. Although fish finders with smaller screens tend to be more pocket-friendly, 7 to 9-inch screens will provide more precise details. Anything bigger than that can be an overkill, though.
Regarding the resolution, it’s indicated by how many pixels there are in each dimension of the display. Normally, the more you can get, the better your viewing experience will be. The bare minimum you can aim for is 240 x 160 pixels. Yet, for a lifelike picture and vivid details, a resolution of 640 x 480 is definitely a good start.
Finally, and above all, remember that color displays are always better than black and white ones. You’ll be thanking us later for this tip when you find yourself in front of an easily readable screen, even in the harshest sunlight.
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6. GPS and Cartplotter
If you go and purchase a fish finder without an integrated GPS and Chartplotter. You’ll be missing the trump card of these devices.
The GPS feature allows you to pinpoint your exact location, mark your favorite fishing spots, and guarantee your safe return in case of emergency. Also, having a Chartplotter is a plus. It enhances the GPS feature by adding defined maps to the unit, which allows you to navigate through the water smoothly, besides entering as many waypoints as you desire.
Not only that, but it also enables you to draw your own maps of uncharted bodies of water and save you the money of buying new map packages since you can chart them yourself.
7. Waterproof IP Rating
You should always check the IP rating of a fish finder before buying because it’ll always be subjected to water splashes and even full immersion. This rating indicates how much water your device can stand without being damaged or impaired.
For example, a rating of four should be okay for fish finders mounted on kayaks since they’ll deal with minimal splashes of water. With a score of five or six, your fish finder would withstand low to high-pressure jets of water.
If you want a device that can come out safely and maintain its functions after being submerged in a 10-feet depth for more than 30 minutes, then a rating of seven is your best choice. IPX8 is the highest rating you’ll find, and of course, it’s the most resistant to water for an extended period.
8. Portable Vs Fixed
One last thing to consider is whether you want to obtain a portable or fixed unit. Portable fish finders come with small and featherweight bodies so that you can travel with them easily in your backpack.
In practical terms, they’re the best fit for fishermen who rent boats or prefer ice or fly fishing. Furthermore, it opens the door to the possibility of using fish finders and select fish finder ice fishing while fishing .
On the other hand, fixed sonars may demand that you own a craft in the first place, yet they get the nod for their better stability and consistent results.
Breaking the visual boundaries between you and the water starts with understanding the specs you’re looking for in a fish finder, and that’s what you’ve just done. Now you can search for the best products on the market and compare their specs like a pro.
On a final note, our best advice would be to establish a budget and walk through the process accordingly. Keep in mind that the amount of cash you allocate for a good fish finder will pay you back with the best catches of your life, and from now on, you’ll rarely find yourself going home disappointed.