Hi Everyone!
How much does everyone use their sidescan in the main lake? I've done fine with traditional imaging/downscan(clearvu for garmins), but I was never able use my sidescan to find concentrations of fish, especially when fishing 30+ feet of water. Sure, in the middle of a feeding frenzy I can see the fish on sidescan, but I had originally found them on traditional imaging/downscan first. Am I missing out on significant number of fish by ignoring sidescan?
I appreciate all input. Thanks!

Yes you are. Here's a screen shot of white bass that Guide Bob Maindelle sent to help me in to distinguishing schooling whites vs. hard rocky bottom.

You are definitely missing out on some fun catching. You don’t have to stage directly over the fish to catch a bunch.

We are sitting in 19ft of water casting out to 35ft. You can see fish under the boat but a huge pack out from the boat up to 100ft out. Those fish out from the boat are not as easily spooked as those that are directly under the boat. Also the bigger the shadow the fish cast, the higher up in the water column they are, meaning instead of reeling off the bottom of the lake 3-4 turns, you may need to reel 7-8 turns. Experiment with your retrieve to determine the best bite.

Thanks for the replies! I wonder if it's my Garmin GT54's sidescan that just isn't as good as the Hummingbirds. Or perhaps I just need to adjust the settings better hahah.
Would sidescan show white bass schools in even deeper water, like 40-50+ feet of water?

AustinWader, I've done, literally, hundreds of on-the-water sonar training sessions with anglers from rookie to pro, and with sonar from entry level to state-of-the art. Almost without exception, the single biggest reason folks can not get all the potential out of their side imaging is due to a failure to level the transducer. This does NOT mean to make it level with the bottom of the boat. This means making it parallel with the lake's bottom when the boat is moving forward as slowly as possible using your outboard, which is the speed at which you are most likely be be side-scanning for fish. Here is a cut-and-paste on how to level your transducer, step-by-step. Note, it works best with a helper.


BOB MAINDELLE: Leveling the transducer is a sonar fundamental
By Bob Maindelle | For the Herald May 3, 2020





Photo Caption: The coins under this level are used as shims to account for the boat’s nose-up attitude on the water when using a procedure to ensure peak sonar performance by leveling the sonar’s transducer.

In addition to providing guided fishing trips, I also conduct on-the-water sonar training sessions for owners of Lowrance, Humminbird and Garmin sonar units.

Having done this for many years now, I have ordered the topics we cover in these training sessions in a logical way.

The first step is inspecting the entire sonar system so I know what I am dealing with and can verify that everything is in working order.

Assuming all is well with the first step, the next step is to level the sonar unit’s transducer. Since I have learned that this phrase ‘level the transducer’ means different things to different people, I will specify exactly what I mean by that.

To level the transducer means to ensure that the transducer’s bottom surface travels parallel to the lake’s bottom at the lowest in-gear speed the boat is capable of going.

Conversely, to level the transducer does not mean to make the angle of the transducer match the angle of the bottom of the boat’s hull. This is a mistake I see over and over again. In fact, a majority of the boats I work on, including newly delivered boats right from the factory or dealership, usually have the transducers positioned in this incorrect manner.

To enjoy maximum sonar performance, the transducer must be parallel to the lake’s bottom. Here is why ... think of a rubber ball; if you release the rubber ball and allow it to fall directly downward, it will strike the ground and bounce right back toward the point it was released from. But if you throw the ball downward at even a slight angle, the ball will not return to the point it was released from.

Sonar’s sound waves behave much the same way. If the sound is directed directly downward, the majority of that sound will bounce right back upward to the transducer. However, if that transducer is canted either forward or rearward, much of the returning signal is lost.

Several symptom can be observed which indicate a non-level transducer. The first is asymmetrical fish arches. Fish normally show as arches on ‘2D’ colored sonar. If the arch has a long left side and a short right side, the transducer is aimed too far forward. Likewise, if the arch has a long right side and a short left side, the transducer is aimed too far rearward.

Finally, poorly leveled transducers typically yield a fuzzy transition between the darker-colored water column and the lighter-colored bottom on down-imaging views, whereas that transition will appear clear and crisp when using a level transducer.

Leveling the transducer is a simple process and one that can be done in a matter of minutes. Working with a partner makes it even easier.

The first step is to obtain a short, approximately 10-inch long water level (bubble level) as would be used for carpentry, etc., and approximately 20 coins (I use quarters, but any coins will do).

Next, launch the boat and drive in a straight line going as slowly as the boat will go while constantly in gear. Choose a hard, flat spot on the boat, like the front or rear casting deck. As the boat is moving forward, place the level on that spot, in line with the keel, or midline, of the boat.

Most boats travel in a slightly nose-up attitude. This will cause the bubble in the level to go to the bow end of the level. Now, using the coins as shims, place as many coins under the stern (rear of boat) end of the level as necessary to cause the bubble to center itself in the level. Take note of both the exact position of the level and the exact number of coins used. Try to keep them in place while putting the boat back on the trailer. If this is not possible, just reposition the level and coins as precisely as you can after placing the boat back on the trailer.

Place the boat back on the trailer and (here is where the buddy comes in handy), drive slowly forward on minimally sloped terrain until the shimmed level once again reads perfectly level, then stop.

If a minor adjustment is needed, the trailer’s dolly wheel can be used to raise the nose of the boat. Take advantage of upward and downward sloping terrain to get the level’s bubble centered.

Once the shimmed level once again reads perfectly level, your boat is now on your trailer at the exact same attitude it was in while moving slowly forward in gear while on the water. If the sides of your boat have a scumline from dirt and debris, you may notice that this scumline is now roughly parallel to the ground, as well.

Now, take the level and place the top edge of it flush against the bottom face of the transducer and in-line with the keel (not side to side). If the bubble is not centered, your transducer is not correctly positioned. To correct this, simply loosen the hardware attaching the transducer to the bracket (do not unscrew the hardware connecting the bracket to the boat). Manually move the transducer until the level reads perfectly level (again, this is made easier with an assistant), and then tighten the hardware to fix the transducer into this new, correct position.

At this point it is wise to use either a scribe, permanent marker or automotive paint marker to make a witness mark on the bracket’s components which will reveal movement if, in the future, the transducer is bumped and moves from this desired position. Making this mark now will prevent having to re-do this whole procedure in the future.

Even inexpensive, entry-level sonars these days are feature-packed and, properly mounted and used, can be effective fish finding tools. Building on the weak foundation of a non-level transducer, however, will render even high-end units powerless to reveal all there is to see under the water’s surface.

Thanks for the reply!

Bob, in your experience how far off perfectly level does the transducer have to be to noticeably affect the sides-scan reading, and does it just not show fish that it should, show them less clearly, or show them in the wrong place? I have usually eye-balled my transducer to be level with the water and now wonder if I need to be more precise.

Remember to check your sidescan setting for deep water vs shallow water.
The high number Mhz will give you great detail in < 20ft of water. Get in 20 to over >30ft and
adjust to a lower Mhz setting.
For Lowrance I use the 800mhz in anything less than 20ft.
if over 20ft the switch to 400Mhz.
garmin and especially Humbird have way better sidescan but principle is the same.

With the latest and greatest, for me the SI is the top aid for finding and catching fish. The SI on my HB unit is always on when I am hunting. I do notice HB has better SI than it's competitors right now.

Also about the frequency selection, the Mega hertz only works well in 20ft or less, it's SI pics are sharp. Deeper than that the Mega frequency can't penetrate and the pics are dark. I mainly set mine lower frequencies to 400khz or 800khz for deeper winter fishing.

Austin Wader
If your sidescan unit has the same freeze frame function with the cursor button as Humminbird.
You can freeze frame a screen while out on lake, open menu and adjust settings on contrast,
brightness etc. while picture is frozen.
Experiment a little with settings, and you may see structures and fish come into focus a little better
on your sidescan pictures. Record your settings for future reference and do the same in differing depths,
the settings will vary with depth and bottom type(mud, sand, vegetation, hard bottom, submerged concrete etc)
I use sidescan out in the gulf at depths to 100' and can see the difference in size of fish on structures
which lets me know which to target, does the same out on the lakes too.

Thanks! I'll try what everyone has mentioned.

Back when I fished for hybrids and sandbass, It was my feeling that , at least on my home lake ( Palestine )
It was pointless to scan any water deeper than 25 ft. Fish deeper than that were always inactive. I looked for active fish ,
15-20 ft. Rarely did I find fish in that depth range that I could not catch, I don't ever recall catching any fish deeper than 30.

your mileage may vary

MO

You should try dead sticking. I've had some really good days on your lake in the deepest water

Dennis, since you are able to put your boat on a trailer, it would be well worth your time to do this right and make sure it is level, using an actual level.

The further from level your transducer is, the less clean (therefore more fuzzy) the transition from the black water column to your colored bottom reading will become on your side-imaging screen. The further from level your transducer is, the more reduced your ability to see well off to the side of your boat will become.

Since you can raise your boat out of the water with your lift, making a "witness mark" from one part of the transducer bracket to the other using an automotive marker or fingernail polish (something bright and bold), will help you visually inspect your transducer for levelness at a glance. If you strike something and your transducer moves, this same witness mark will help you manually adjust your transducer back to the correct position, so you only need to go through this leveling process once.

Here is a photo of the witness mark on one of my transducers... I used a Dremel tool to actually engrave a groove from one part of the bracket to the other. When these two grooves align, I know my transducer is level. I glance at it as part of my pre-launch routine each time I launch.

Bob, thanks. Good stuff! I am going to use a level, adjust the transducer, and see how it makes a difference.