An extremely popular fishing accessory these days is an electronic device called a fish finder, a name that is not entirely deserved as these fish finders don’t actually “find” the fish for you. So why the dishonesty? Because what this marine equipment can and does is peer into the murky depths to reveal what lies below your boat and then shows you, via a graphical display, things like water depth, sunken trees or other hidden obstacles, weeds , even water temperature. And yes, if there are any fish there, it will also show up on the sonar screen.
Fish finders began as an offshoot of military technology developed for submarines: In the 1950s, in a moment of genius or madness, fishermen began using large, heavy (not to mention bulky) vacuum tube sonar units. ) to search for fish. In 1959, Carl Lowrance, along with his sons, succeeded in miniaturizing sonar equipment using transistor technology and began selling battery-powered units. Modern marine electronics and display technologies have evolved to allow fish finder manufacturers to develop and produce ever smaller and more powerful units with a wide range of features.
All fish finders use sonar: sound waves are sent through the water through a transducer. When the sound waves hit an object, they bounce back and reappear in the fish finder for viewing on a screen.
What is a transducer, you might ask? Well, it’s simply a device that converts one form of energy into another. In this case, that means it converts the electronic signals from your echosounder into sound waves and then converts the echoes back into electronic signals so your sonar can display them. As the sonar waves are emitted from the transducer, they gradually expand in size and create a cone-shaped pattern. Anything inside this cone will be displayed on the fish finder screen.
Anglers should use the correct cone angle for their fish finder, depending on the depth of the water where they are fishing. Shallow and mid-depth waters require a wider cone beam than deep waters. Some fish finders use only one cone beam angle, while others allow users to switch between two or more cone angles.
Early screens had dials, a bit like the speedometer in your car. Bright lines would appear at the depth at which the sonar detected fish. Even today it is possible to buy more advanced dial models. Many less expensive fish finders have black and white LCD screens, while higher-end models use color CRT screens.
LCD screens have lower resolution but have a slight advantage in that they are often easier to see in sunlight and in most cases are more durable and waterproof. Color displays have higher resolution and therefore display more useful information by color coding fish and features of different sizes.
Manufacturers are now combining fish finders with other technologies such as GPS and chartploting. This is especially attractive to anglers who sail and fish in open water. Another useful development is side scan, which not only allows you to see what is below your boat, but also shows what is to the sides of your boat through the use of side scan transducers.
Due to the large number of makes and models available, selecting a probe can be a bit overwhelming. When choosing a fish finder, there are many things to consider such as display unit, power, transducer, depth, and display resolution. Let’s take a look at some of the details you’ll need to know:
Step 1: Decide which features are important to you, complement your fishing technique, and are within your budget.
Step 2: Fish finders can be both portable and mounted. Choose a mounting style and location, such as the dash, and measure the available space. This will narrow down your selection based on the screen size that actually fits there. A smaller boat may need a small screen to be mounted near the transom. Some portable units come with a transducer that attaches to the hull of the boat with a suction cup. The use of portable fish finders on kayaks has increased dramatically in recent years. For permanently mounted transducers, a hole is drilled in the hull away from any supporting turbulence. Kits are also available to mount fishfinder transducers to trolling motors.
Step 3: Check out the power ratings of fish finders in your range of choice. The effectiveness of a fish finder in deep or murky water has a lot to do with its power rating and the frequency of the transducer signal.
High powered fish finders capture more detail in murky water and are more reliable in deeper water. Manufacturers will usually express the power rating of the unit in watts.
There are two basic operating frequencies for fish finders: 50 kHz and 200 kHz. The slower 50 kHz units work reliably at greater depths, while the faster 200 kHz units capture more detail at moderate depths. As mentioned above, some fish finders work on only one of these frequencies, while some allow the angles to switch between them.
Step 4: Review the available transducer styles and decide if you need a single or dual frequency transducer, what cone angles you need and the type of installation, ie transom mounted, inboard or through hull.
Select single-frequency transducer models if fishing in shallow rivers or lakes, or along shallow coastal banks. Dual-frequency transducers are best for those who fish in deep lakes or offshore deepwater fishing areas.
You must match the frequency of the transducer to the sonar unit. For example, a 200 kHz sonar unit requires a 200 kHz transducer. The cone angle of a transducer determines its coverage of the underwater world. The wider the angle of the cone, the greater the area covered. Generally use a wide cone angle for fishing at shallow to medium depths. The narrow cone penetrates to deeper depths, but shows less fish and structure due to its narrow beam.
Step 5: Choose a fish finder with a suitable depth range. This ties back to Step 4: The deeper the region you fish in, the higher the depth rating you should select for your fish finder. Depth classification is the ability of sonar waves to penetrate deep and protruding areas of deep water.
Step 6: Select a sonar with a color resolution display if you live in an area with frequent gray or cloudy skies. If you plan to use the fish finder on a boat without a cover, choose one that has a high resolution as well as a UV-reducing film over the screen.
So do you need a fish finder? If you want to win the fishing game hide and seek, the answer is yes.
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