Reading Your Sonar Through An Eight Inch Hole
by Mark Leadens

"There he is, can you see it?" This was my question to the rookie ice angler that had hired me to take him and a friend out on a big central-Minnesota lake for some winter walleye fishing.

"You mean that red line right under the yellow line is a fish?" was his reply. The fish answered his question as the two lines merged and the tip of his rod bent with the weight of a nice three-quarter pound perch.

"You can actually see the fish with one of these things," were the next words out of this now-excited anglers mouth. I just couldn’t help but smile as another fisherman began chipping away at the wall between owning a sonar and knowing how it works. It just takes some practice using it, and it doesn’t hurt to get a few tips along the way.

While I would like to be able to take each and every one of you readers out and show you how to get the most from your sonar, I’m afraid I won’t live that long. Hopefully what I can pass on to you in the next few paragraphs will help you knock a few bricks out of your own wall.

In the winter I use a flasher-type sonar made by Vexilar called an FL-8. Some of you may have other types of flashers and some of you may have liquid crystal display (LCD) type graphs. These all work to locate fish and tell you what kind of depths you’re dealing with, as well as what type of bottom your over and where your lure is positioned. The key is to trust your electronics.

The first thing to do is make sure your batteries are good and charged. Some sonars use standard D-cell batteries, some use small gel cells. I have a Blue Box for my FL-8 that uses an enclosed lead acid battery that is of a deep cycle nature and can be charged fully after each use. I hate to think about going out on the ice and having the depthfinder quit after only an hour or two. It happens to my fishing buddies, it won’t happen to me.

The transducer I use is self-leveling. When I set it in the hole it balances out and stays perfectly level. If you have the type of transducer that is attached to an arm you need to put one of those little stick-on bubble levelers on top so you can make the transducer perfectly level once you position it in the hole.

The reason the transducer has to be level is because you are only fishing in a six to 10 inch hole. You have to know what is directly under the hole to be efficient. It won’t help you much to see what’s off to the side.

Plus you want to be able to see your lure. With the transducer level you will be able to see the lure perfectly as it drops straight down the hole, and you will be able to see the fish perfectly as well, as they swim up to check out what could be their last meal.

When I say trust your depthfinder I mean you have to believe what it’s telling you. If you see fish swimming up to your bait and they’re not biting, it’s your presentation that’s the problem, not your location.

You can tell a fish is there because it actually shows up on the flasher as another line usually moving up from the deeper water to your bait. This is in fact usually a fish that’s moving in from the outer edge of the transducer’s cone up to you bait making it look like it’s coming off the bottom.

With my FL-8 I can actually tell where that fish is in the cone by the color of the line. A green line means the fish is sending back a weaker signal and is on the edge of the cone. A yellow signal means it’s a stronger signal, and red tells me that fish is right below.

There are other things that the sonar can tell you that can be important. A thick line for a bottom mark means the bottom is harder and sending up a stronger signal. A thin bottom line is likely a soft bottom.

Lots of marks that aren’t moving between the lake bottom and the ice are probably weeds. If your finding a patch of short weeds in deeper water that’s a great sign because there are probably some other lines on the flasher that are coming and going in and out of the cone that are fish.

It’s important that you get a good reading on your lure. You want to be able to put the bait right above the fish. Too high or too low and you may not get that fish to move to the bait.

Anytime you see a mark that’s way up off the bottom it’s probably a fish. Many times I’ve pulled my bait up to within a few feet from the hole only to get bit by a big fish lazily making his way by through the open water. Which means it all goes back to the number one rule in using your sonar for winter angling. Trust what you see.

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