W2F Blog

Understanding Sonar, Side and Down Scan will improve your fishing

By Jason Sealock

Technology changes yearly, monthly, weekly, daily it seems in today's society. The changes range from making dinner a little easier to treating cancer with advanced scanning and dissecting technologies. Technology in fishing seems to be a hot button topic. Absolutely you can catch bass without a single piece of electronics technology in your fishing boat. But put yourself on a 100,000 acre reservoir and breaking down a new body of water can feel more like finding a needle in a stack of needles.

Those of us that grew up using flashers have forced ourselves to interpret what a ring of pulsing light means in terms of fish, cover and forage around us. Then as paper charters came into popularity, it was cool to be able to draw contours on to a roll of scrolling paper. Next entered the liquid crystal displays and we again had to learn that a fish was a shallow tapering arch or saucer on the screen. Moving active fish under a stationary boat were spaghetti lines on the screen.

Now we truly live in the golden age of depth finding technologies. We have available to us side imaging and down imaging technologies, HD sonar that can actually look into cover and see fish. Yet with all this technology available to us, the most requested topic I get from anglers involves interpreting what they see on their sonar, or Down Scan or Side Scan imaging.

We're going to work on sharing some cool screen shots and then walking through what's there. No it's not going to be a bunch of underwater things that never hold fish. It's going to usually be fish, forage and the cover the fish are relating to during different seasons. The goal will be to provide anglers with the knowledge to be confident when they scan over something that they are seeing what they think they are.



This is the first screen from my Lowrance HDS 8 Gen2 Unit. Now folks will look at this and say they see the bass. It's a little easier to say that when someone shows you a screen knowing they are going to show you fish. But when you encounter this on the lake you're looking for the position of the fish on the screen as well the marks and arches .

Let's start however with orientation on the three screens. It's important to note where your boat is on each of the three screens technologies. We've place a red triangle in each pane. That is the current location of your boat on each screen. Always.

The left pane is side imaging. The boat is orientated at the top middle. Now anglers often mistakenly think when they set their side scan area to 40 feet they are scanning out 40 feet to either side. No not really. You'll notice our depth is around 23 feet. On the ranges on either side the bottom starts being drawn at 23 feet. What you are seeing is directly below the boat on the left and on the right. Then from there it starts scanning out. So really it is scanning out to the "side" roughly 17 feet. The depth alters how far "out to the side" it images. Because it has to look down and then out.

The other thing folks don't realize is by setting your side scan to a large range, say 100 feet, you're looking for cover or structure because the bass will be too small, mere specs of sand on the screen.  I like to set my range outward about 30-50 feet depending on how deep I'm fishing or looking for schools of bass because I am often looking for the actual fish. Unless I'm looking through open expanses of water searching for isolated pieces of large cover.

In this screen, we see a school of bass hunkered down around the bottom in 23 feet of water on all three screens. I placed 3 circles on the exact same group of fish in each window. Again it's about perspective.

On the right side I have it split showing down scan and sonar together. One thing to note, and why I often switch to the three screen mode when I'm searching, the side scan screen shows me roughly 28 catchable bass. The sonar shows me about half that. What you often get with side imaging and down imaging is better separation and less masking. Sonar looks downward in a conical spectrum while side imaging and down imaging to a degree look down and outward more as a sheet fed scan, so the way they interpret will be vastly different.

Then as I stop to fish, I often go to straight sonar or sonar and GPS split screen. That's because Structure Scan needs the boat moving to paint an accurate picture. On the Lowrance units, it actually matches the speed of the scan to the speed of the boat. If you go to slow you get elongated distortion. So I often scan at roughly 4-6 mph.

When I'm not moving, sonar will just constantly echo returns and what you see is a continuous line as it re-pings the same object over and over but the screen is scrolling so the result is a line moving up and down or multiple lines moving up and down instead of a single dot as you pass over quickly with side scan.

Now back to the orientation aspect. Yes I've caught a lot of bass suspending, but I've caught way more bass that are relating to the bottom or some form of cover. In this picture it's also good to note the bottom hardness. The Down Scan illustrates a hard bottom.

As you pass from a soft bottom to a hard bottom on side and down scans, the bottom will get much brighter (i.e. a stronger return). Bass in deep water like hard bottoms.  When you mark fish positioned on a hard bottom in deep water and they are orientated horizontally along the hard bottom, they are often bass. I don't like to see short clumps of fish stacked up tall on the screen. Typically that is what white bass, yellow bass, crappie, even species like drum do.

Bass when they are actively corralling bait fish on the bottom will position more horizontally along the bottom over a long space, rather than straight up and down in a small space.

Now size can tip you off to what is on the screen too. IF those arches were larger and appeared almost "hairy" on the screen, they are generally rough fish. For some reason, the denser the fish (or harder the scales like on rough fish) the return almost looks like an arch or spot with hair draping off it. Also notice how much a foot would be if the dark space on the side scan screen on the left has 23 feet in it on either side of center. So I've come to realize when I see fish of this size at this 40 foot scale in 20 feet of water, I know they are bass.

Perspective is everything when looking at electronics. If the fish seem too large on a small scale, they probably aren't what you're looking for. If they are stacked up tall, again they may not be what you are looking for. But when you see them orientated along the bottom, you're going to figure out a lot quicker what's going on down there under and out to the side of your boat.

We'll work more on sonar, some of the settings to help you get the most out of your units in our next installment of Fishing Technology and feel free to send us suggestions on what you want to see.

If you liked this, you'll probably like these two articles on finding and catching suspending fish with sonar and imaging:

Bridging the Gap on Suspended Bass Part One

Fishing Suspended Bass Around Cover Part Two

And this video:

How to Read Your Electronics

Cranking rip rap can be a quick remedy to tough river fishing in the fall
by Walker Smith

There’s no question about it—fishing rivers in the fall can be quite challenging. Gone are the simple spring fishing days of multiple kickers in the livewell and plenty of 2-pounders to boot. By the time autumn rolls around, bass are skittish, leaving many fishermen scratching their heads. Rest easy, fellow anglers—cranking rip rap is a great way to combat this age-old conundrum.

Forrest Wood Cup champion Jacob Wheeler has spent his entire life perfecting his fishing skills in river systems throughout the Midwest. He recently shared some of his favorite tactics and crankbaits for tackling fall’s notoriously tough river fishing.

More: How did Jacob win the FWC?

The difficulty of fall river fishing
In order to increase your river fishing success in the fall, it is necessary to understand the correlating biological aspects. As the unforgiving heat of summer fades and the days begin to shorten,  shad instinctively embark on annual migrations towards shallow water. Many of the country’s river systems lack adequate backwaters and feeder creeks.  Without an abundance of creeks to draw migrating shad, effectively locating large concentrations of bait can prove to be quite a challenge.

In addition to the lack of feeder creeks, many river systems experience dramatic drawdowns throughout the fall months. With the dropping water, both shad and bass have a very limited amount of cover and structure.

“Low water levels can make fall river fishing even more difficult,” said Wheeler. “Bass can’t set up on their accustomed cover, and it takes a lot of the visual element out of fishing. That can be tough to overcome at times.”

Another difficulty of fall river fishing can be attributed to the fishing pressure that the bass have been exposed to throughout the year. Bass are smart creatures and become weary of the traditional baits that we use to fool them.

“A lot of the bass that we pursue during the fall have been caught once, maybe even twice before,” Wheeler said. “Every weekend these bass get bombarded with worms, jigs and crankbaits, and by this time of year, they are able to tell the difference between the real deal and something artificial.”

Productive areas
With the days getting shorter, it is important to maximize your fishing time, and keying in on specific areas will produce more out of your limited time on the water. Due to the lack of migration options for shad and a decrease in river current, “pinch-points” within the river are essential to fall fishing success. If you can locate an area where the river becomes increasingly narrow, a solid mixture of shad and bass are sure to be in the area.

“I have caught a ton of fish over the years locating these key pinch-points,” Wheeler said. “The corners of bridges are solid starting points, as they are primary travel routes for shad, bottlenecking the fish into a smaller, more confined area. If bridges are few-and-far between in your area, spend some time locating shallow sandbars and small current eddies around rip rap.”

When Wheeler locates rip rap on the river, he focuses solely on any irregularities in the rip rap. Irregularities are considered to be anything that is different from the surrounding rip rap—such as transition areas leading from small-to-big rocks or vice versa, grass patches or anything that may block even the smallest amount of current.

“David Fritts won the FLW Tour Guntersville event in 2009 by focusing on very small, seemingly unimportant irregularities on rip rap banks,” Wheeler said. “He caught the majority of his fish slamming his crankbait into just one rock. If his cast missed by just an inch, he wouldn’t get bit. That is the epitome of fall river fishing.”

While Wheeler occasionally uses his electronics to locate key areas in rip rap banks, expensive electronics are not a necessity. Obvious areas that many anglers overlook include outside river bends, steep channel-swing sections in the bank and large, visible boulders that may block current.


Key depths and presentation
Deep crankbaits definitely have their place when fishing rip rap in the fall, but in the river systems where fish tend to stay shallower throughout the fall, Wheeler opts for a more shallow, power fishing-friendly approach.

“When I’m cranking river rip rap, I only target fish in the 3- to 5-foot range,” Wheeler said. “I feel like I can get a lot more reaction bites doing so. I like to slam my crankbait against shallow rocks as hard as I can, and then pause it for about a second. Most of the time they will hammer it while it’s sitting still.”

Wheeler heavily stresses the importance of finding the proper cadence when power fishing rip rap banks. The fish’s preference can change daily, so it is essential to experiment throughout the day until you discover an effective way to draw strikes.

“Most of the time, I will burn my crankbait through the area, stopping it every time it collides with something,” Wheeler said. “Even though that’s where my confidence is, I still make it a point to periodically change my retrieve. Being very mindful of your cadence can be the difference between a good day and an awesome day.”

Perhaps the most important element to Wheeler’s fall rip rap success is his casting—not necessarily making circus casts into hard-to-reach areas, but paying close attention to the location of his bites. As David Fritts demonstrated in the 2009 Guntersville event, rip rap fish can get very keyed-in on specific pieces of cover. When Wheeler forces a reaction strike from a bass, his first objective is to see exactly where the fish bit. If the fish bit in front of a small grass patch for instance, Wheeler will make several repeated casts to that particular grass bed, while searching for additional areas to duplicate the pattern.

“Don’t be discouraged if you don’t catch a fish in your first few casts,” Wheeler said. “I’ve caught some really big fish after 30 casts to the same exact area. You just have to pay attention to when and how you’re getting bites. Did you stop it? Deflect it? Run it up a little shallower? You have to figure out why it bit and why it was in that specific location.”

Targeting gnarly rocks when fishing river rip rap is a great way to mangle your line in a hurry. After every five casts, it is important to inspect your line for any nicks, abrasions or rough spots. In the days of $10, $15 and sometimes $20 crankbaits, proper line care is a must.

“You have to check your line constantly when you’re fishing like this,” Wheeler said. “I’ve recently upsized to 12- or 14-pound line because the rocks can be really nasty. When I’m targeting such shallow depths, I don’t really care what my line diameter is—as long as my line holds up. Whatever you do, don’t be lazy about re-tying.”

Rod angle is an often-overlooked element to rip rap fishing. Chunking and winding will work at times, but again, successful river rip rap fishing in the fall is a very detail-oriented technique.

“I like to hold my rod tip down and to the outside of the boat as much as possible,” Wheeler said. “I don’t like to simply skim my crankbait across the top of the rocks. I want my rod tip down in order to feel everything that my bait is doing. On occasion, I’ll hold my rod tip up in extremely shallow situations, but down and to-the-outside is definitely my preference.”

Not only does the proper rod angle let you feel the bait better—it also helps control the depth of your crankbait. While a Rapala DT Flat 3 will run approximately 2 feet deep with a high rod tip, the same bait will run 4-feet deep with a low rod tip. In this game, two feet can make a world of difference.

Boat positioning
If you drive over the bridge of almost any river during a busy Saturday, you are likely to see several bass boats lined up on the rip rap throwing perpendicular to the bank. While it may be easier than throwing parallel to the rip rap, fishing perpendicular is the quickest way to minimize your success.

“When I’m cranking river rip rap, I can literally touch the rocks with my rod tip,” Wheeler said. “I want to get right up on the bank to ensure that my crankbait stays in the strike zone for as long as possible. If you fish at a 90-degree angle to the bank, your crankbait will only be in the strike zone for about two cranks of the reel handle, which is never good.”

While fishing closely to the bank will produce more fish, it requires some special attention to detail. Wheeler prefers to set up his cast in a manner that allows him to execute a sweeping hookset to the outside of the boat. Doing so will not only protect your rod from the rocks, but will also help minimize the chances of the fish breaking you off in the rip rap.

Throwback lures can still be very viable bass fishing options