Fish finder is known as one of the must-have accessories for any fishers. It is a sonar technological instrument used to locate fish underwater. Using fish finder means to analyze the reflected sonar beams. Then, convert received information to images showed on a screen display.
This modern instrument integrates functions of a radar detector, compass, and GPS system. That way, it can allow anglers to know the exact location of the fish, the other subjects underwater, and the structure of the underwater world. Therefore fish finder is favored by many professional anglers and even casual fishers around the world.
Fish Finder Features
Structure scan is a feature that enables fish finder to display the images of the bottom and two sides of the boat on screen. It uses a transducer providing three-dimensional images of the area under the boat, including the natural structure of the water bottom and location of fish.
Particularly, those received images are quite clear because this function operates at very high frequencies (about 455 kHz and 800 kHz). The transducer has a large scanning area up to 180 degrees. That’s why it can allow anglers to identify the rocks, bushes, and another spot where fish are hiding. Also, it can easily see the exact location of the boats on the water.
Down imaging is an additional feature of the modern fish finder made from sonar technology. This feature will give you the truest and vivid images of the water bottom by emitting high-frequency sound waves in very thin slices. These slices generate two-dimensional images through the returned sonars.
A breakthrough technology of Humminbird will help you see clearly what is on both sides of your boat by using high-frequency waves. This gives you clarity of images. Side imaging uses extreme thin radar beam to scan a 480 feet area includes the left and right of the ship. The gathered images will build up the overview of the bottom so you can zoom in or mark the location.
Dual beam uses two different sonar beams to scan a wide area in a more specific way. One is a narrow, high-frequency sonar beam that gives detailed images of a smaller area. On the contrary, the other is a wide and low frequencies sonar beam, and it provides less detailed images of an extensive area.
On the screen, you will see two separate images or blended into one, so you can get the best images. You can use one of the two beams, or combine them together to get information from both at the same time.
Guide to using fish finder effectively
The transducer must be mounted properly. Otherwise, the fish finder will not give you the best performance. Remember to choose a mounting spot on the hull that is always submerged. This is because transducer must be in contact with the water all the time when the boat is trailered, or else it will not work.
Additionally, make sure the transducer is mounted horizontally and fixed when the boat is running. Although mounting transducer is a labor-intensive job, you can still do it on your own by reading and following the manufacturer instructions carefully. Or in some cases, you just need to ask a handyman for help.
Although in the ideal environment we move quickly and find fish easily, the reality is different. When we are not moving, the screen shows for more details, but the instrument has its limits. The more we move, the more difficult it is to see a clear image. The maximum speed allows us to see fish clearly is from 5 to 6 km/h. In good conditions, we can increase the speed to 7 or 8 km/h.
Moreover, the water wave is 4.5 times as fast as the air wave. Therefore you cannot read fish finder screen accurately when it is out of the water. Most of the fish finders are adjusted to be read precisely at the depth with wave speed of 120 km/s. In fact, the device can even be read faster when you slightly lean it forward 2 to 3 degrees and less than 1 degree when on the boat.
There is one important thing you need to remember. That is the high frequencies are effective for fishing in shallow areas, while lower frequencies are suitable for great depths.
Specifically, high frequency likes 455 kHz gives more details and wider coverage, but it is not useful in the deep water. 200 kHz frequency is more common as it gives effectiveness in deep water with clear images on the screen. Low frequencies from 50 to 83 kHz are good for transmitting to great depth though some details may disappear or get blur.
Users need to understand information on the first vertical line at the bottom right on screen because it says exactly what is happening under the boat. When vertical lines appear and move from left to right, they represent what was in the past and no longer exists.
For example, 40 vertical pixels lines mean 39 of them show what was detected and passed when the boat is moving forward. Available fish finders on the market usually have 160 to 480 vertical pixels.
GPS is a navigation system that is widely disseminated and favored by many anglers. Why buy both GPS and fish finder while you can completely use a combination of them? This device is called the chart plotter, as it records your location and display objects and natural structures underwater. The most important reason why it is highly recommended is that it will help you find the way back home when your boat is far from shore.
A fish finder has a self-regulating program’s system for people who don’t like to change the program or do not understand about it. Conversely, if you want the instrument to be more powerful and more efficient, use the zoom for clearer images. Then gradually increase the sensitivity for more pixels appears on the screen.
Distorted signals on screen are called interferences, which often happen in deeper than 10 meters area. This is because fish finder cannot go deep enough and only utilize in about 3 to 4 meters depth. To avoid this situation, you should use two separate batteries, one for the boat and one for the fish finder. Do not forget that two wires connected to two batteries have to be far apart, or you have to cover batteries with a rubber cover.
Tips to tweak fish finder
For Humminbird fish finder
Water type: Some units have water type setting. If you select deep water, it will change the sensitivity and filtering by the definition of deepwater type. That way, you can change and adjust things as you like.
Freeze frame: With side imaging feature, whenever you move the cursor and zoom an object, the area around it will be displayed on the screen. Thereby you can inspect and mark the area.
For Lowrance fish finder
Color Palettes: Most current Sounders have expanded color palettes. White palette works best under the sun while sepia palette gives the most detailed target when using structure scan feature. White palette and blue palette can help you determine water bottom hardness with the best view.
For Raymarine fish finder
Sounder and plotter integration: This is a great combination of information in the most specific way. By combining received images with GPS and charts, you can mark areas that have a lot of fish, or track and predict their movements.
Color Threshold: Nowadays, most Sounders use the bold color palette, as it represents the signal strength. By using the clutter control called color threshold, you can delete unwanted objects based on their colors showed on the screen.
Shallow water’s clarity enhancement: Images received from deep and shallow water cannot be clear all the times because of the closer the transducer to the target, the stronger they reflect. To solve this problem, you can use the TVG (Time variable gain) feature to reduce the sensitivity of shallow objects while increasing sensitivity of deep one.