Five Tips for Finding More Fish with Side-Scan

Seeing sideways can help you catch more fish, and these five tips will help make it happen. 

Side-scanning sonar can provide spectacular views of the watery world. Photo courtesy of Garmin. 

See those little dots right there? Cast 45-degrees off to starboard and get ready for the strike. But you’ll only know how to spot those fish if you know how to best use that side-scanner. Like any type of marine electronics it takes time, experience, and know-how to best utilize the tech. So, where do you start? There’s no substitute for time on the water — but these five tips will help shorten the learning curve. 

1. Get accustomed to playing with range and zoom. If you have multiple large screens at the helm you can view multiple ranges and different zoom levels at the same time, but most of us have limited screen space. And side-scanning views can deliver radically different data depending on just how large a swath of water you’re looking at. Obviously, being able to see through larger chunks of territory has its advantages, but the returns for all that space have to be compressed down to the size of the screen on your helm. What looks like a tiny dot of little note at far range may turn out to be significant when you zoom in on it. And while you may not be able to see faraway items on a short-range setting, getting a close view can expose details you never would otherwise notice. Think of it like scanning the horizon with your bare eyes, then using binoculars to focus in on specific items you’ve spotted. 

Viewing both sides of the boat is the default, but when you know the target you want to view is off to one specific side you can double the available screen space by viewing one side only. 

2. When you more or less know where an item of interest is, fill the screen with a single-side view. Again, this relates to utilizing LCD screen space in the most effective way possible. Say for example that you know a big school of bait is off to starboard and you’re creeping along looking for large returns to see if any cobia or redfish are hunting them. Why eat up half the screen space you have available, with the port-side view? 

Long structures like a jetty are ideal for side-scan experimentation — oh, and for catching fish, too. 

3. Learn your speed ceiling. Just where it will be depends in part on which system you’re using, what kind of boat you have, and the transducer installation, but with many rigs the difference in what you’ll see between moving at seven or eight knots versus five or six knots can be huge. Experimentation is really the only way you can nail down the best scanning speeds for your rig, so play around a bit until you feel comfortable that you’ve found your upper limits. Tip: as a starting point, go to a bridge, jetty or similar structure-rich target, and make multiple passes at ever-increasing speeds to get a feel for how the view deteriorates as your speed increases. 

4. Make waypoints — lots of waypoints — when you’re prospecting structure. These days, all of the systems out there allow you to tap the screen and create a waypoint on a side-scan return. When you’re prospecting it can be tempting to stop the boat and start casting as soon as you see something cool, but a much more effective way to gather intel over a large area is to search it all at once via a grid pattern and create waypoints as you go. It’s helpful to dedicate a unique waypoint icon to the task. Afterwards, you can fish them one by one and delete those waypoints or change the icons to ones indicating a hotspot, depending on what you find when you investigate them further. Note: a great time to use this tactic is during a slack tide or a dead bite. Spend an hour or two of dedicated prospecting, and by the time you’re done the fish might be biting again. 

Slight transducer adjustments can have a dramatic effect on your side-scanning results. 

5. If you seem unable to get the system to provide the results your compatriots enjoy and/or you’re unhappy with your side-scanning performance, adjust the transducer. Transducer placement has a huge impact on performance and in many cases a less-than-ideal transducer location more or less ruins the results. Moving it an inch or two (or sometimes even less) up, down, left, or right can have a dramatic impact. 

Will a side-scanner turn you from a Googan into a highliner overnight? Of course not. Like we said at the beginning, there’s no substitute for time on the water. But if you apply these five tips and combine them with experience, your coolers will grow heavier and heavier by the season. 

Lenny Rudow …has been a writer and editor in the marine field for over two decades, and has authored seven books. He is currently the Angler in Chief at Rudow's FishTalk Magazine, is Electronics and Fishing Editor for BoatUS Magazine, and is a contributing editor to several other publications. His...