The Fish Finder - Part 2

How To Use a Fish Finder

Last time I talked about choosing the best fish finder. So today I'm going to help you learn how to use your fish finder.

I'll never forget when I was starting out as a young bass fishermen; I had never even heard of a fish finder. Until I saw a guy on tv with this new contraption that looked like a small TV which allowed him to actually see the fish under the the water. I was absolutely fascinated! I was sure that if I only had one of these, I could catch all the bass I wanted. All I would have to do is ride around until I saw a bunch of fish under the boat and catch them. It seemed like this fish finder thing would make catching fish a snap.

Well, needless to say, it didn't work quite that way. Although, after a few years of experimenting with, and using fish finders, I did come to realize that they are an extremely valuable and almost essential tool for catching bass in deep water.

Fish Finder Settings

In order to get a clear accurate reading on a fish finder, it's extremely important to set it up correctly. Settings and functions vary depending on the brand and type of fish finder you have; if you have a new 3D unit, I'm sorry, but I have no experience with those; settings may or may not be the same. Most units however will allow you to set the following.

For settings I'm going to start with the depth scale. In Part 1 of this post I touched on the depth scale. I believe it's essential that any fish finder have a manual mode function for the depth scale. This is even more important if you're learning to use a fish finder.

The automatic depth scale allows the unit to show bottom depth in different scales. For example if your boat is in 10 ft of water the side scale on the screen will be showing 0 to 10 ft then you come over a spot where the bottom drops off to 20 ft, the scale will change automatically from 0 to 10 ft to 0 to 20 ft.

The default depth scale setting for most fish finders out of the box is set on automatic. I recommend changing the setting to manual. Running the automatic scale takes away from the power and can become confusing if it's constantly changing scales as you move over bottom changes. If you're not interested in anything that's more than 40 ft deep, manually set the scale at 0 to 40 and leave it. You can change it anytime if need arises.

Next is the digital depth setting. If your unit allows, turn it off. This function is another power sucker and you can use the side scale to read depth.

Sensitivity, The sensitivity basically turns the units power up or down. For the maximum clarity and detailed readings you will want to run the the sensitivity as high as possible without getting noise or static on your screen. This setting will often need to be re adjusted to compensate for water conditions. For example if you're in muddy or dirty water and are getting static on your screen turn the sensitivity down just enough to get rid of the interference.

Grey Line. The grey line represents the bottom on your fish finders screen. This function can give you much much more information than just the depth and contour of the bottom. I'm going to talk more about grey line in a moment but for the settings you'll want it just dark enough to give good contrast in the lower and upper.

Chart Speed, Chart speed controls the speed that the chart scrolls across the screen. This setting should be set at maximum speed
The only time it should be set slower is for extreme depths such as 100 ft or more which never comes into play in bass fishing.

That has your main settings ready. I recommend you turn off any and all bells and whistles such as alarms etc. These things can be fun to play with and useful in certain situations but if you're learning to use your fish finder they're just a distraction. Most are simply put in units as a selling point. The only exception to these is the chart cursor. The chart cursor is a very useful function for pinpointing the exact depth of fish or other objects. You should keep this function turned on.

How To Read Your Fish Finder

A fish finder does find fish; but not always in the way you may think. After a few years of experience with my fish finder, I realized that it is much more valuable for finding the places fish live or the schools of bait that they feed on than for seeing the actual fish themselves.
This is especially true with bass. Bass are very cover oriented. When they get inside thick cover such as weeds or brush, you may see the cover on your graph but not the fish. If you do see fish around the cover it's a plus. But NEVER EVER let not marking any fish on your fish finder when you run over a good piece of cover or structure be a reason for not fishing it. I can't tell you how many times I've caught limits of nice bass off a spot that I graphed with my electronics and never saw a single fish.

There is no magic article or book that can instantly teach you to read your fish finder . However, with experience you will eventually be able to read your graph well enough to know what you're seeing on the screen at all times. Once you become experienced with this tool, you will be amazed how much information the fish finder can give you about whats under the surface of the water.
Just for example, a couple things that you may not know the fish finder can tell you: 1 the grey line which represents bottom can tell you the bottoms composition. A wide darker, or double grey line represents hard bottom and a narrow or weak gray line represents soft bottom. 2. A darker band on the screen between the bottom and surface is usually a thermocline. A thermocline is the depth where water temperature changes. This will normally come into play in summer when the upper layer of water is warmer than the deeper water. Bass like to be near the thermocline when water surface temps are very warm.

For those of you who have never used a fish finder at all, here are a couple good videos that should help give an idea of what fish, schools of bait and different types of structure and cover look like on a fish finder. fish finder Video 1 fish finder video 2

How to know where objects or fish are in relation to the boat.

The transducers cone angle determines how large the area you view on your fish finder. To give a more detailed explanation, the signal leaves the transducer and spreads wider as it travels down, hence the term cone angle.

I briefly touched on transducers and cone angle in the last post. I recommended that beginners use a standard 20 degree cone angle transducer which is commonly included with most fish finders. Without getting too technical, just to give you an example of the size of the area you'll be viewing on your graph: With a 20 degree cone angle transducer over a 20 foot deep bottom, you will be viewing a 15 foot radius of the bottom. Basically when you are traveling at idle speed, as soon as an object comes on to your screen the object or fish is directly under the boat. Once the fish or object is in the center of your screen it is behind you.

If you have your units settings correct. Arch shaped lines will indicate fish. However unlike the simulations you see on fish finder ads, you will seldom see complete arches. The reason for this is, the fish must be directly under the center of the transducer to get a complete arch. Normally fish will be to the sides causing your reading to be half arches or if the fish are moving, you will see a continuous long line; sometimes all the way across your screen.

Fish Finder Tips

Always check the fish finder transducer before putting your boat in the water. Make sure the transducer is level and not pointing back or forward.

Most fish finders have a simulation mode. You can use this to practice with your unit before you even put it into use on the water. It will also help you learn to identify what you're seeing on the screen once you get on the water.

Use a buoy marker on deep water structure or cover. When you see fish or structure that you want to try on your fish finder, drop the marker to mark the location. Keep in mind that the actual spot will be behind you when you drop the buoy.

Mount a fish finder on front of your boat and the transducer on bottom of your trolling motor. With your sensitivity setting turned up, you can actually see your lure on the screen and its location in relation to the fish or cover. Many time you can see the fish move up and strike your lure.

Once you are experienced with your fish finder, you will realize just how valuable this tool is for catching bass. There's a lot to learn about using electronics in bass fishing. I know I have not addressed every question that you may have on the subject. So feel free to use the comments below to ask any questions you may have on how to use a your fish finder; I'll be happy to answer all questions as best as I can.