Fishing Sonar on the Edge

Fishing Sonar on the Edge

Fishing Sonar


Sonar and GPS navigation continue to advance by leaps and bounds, offering tech-savvy anglers ever more options for exploring the underwater world and charting a course to success. The trick is keeping up with it all.

On the sonar front, side- and 360-degree scanning breakthroughs remain big news, but they've been bumped from the front page by new technology that opens the door to the third dimension. Not to be overlooked are cutting-edge acoustical gains in compressed pulse, broad-spectrum sonar, which raises the bar in sensitivity, noise rejection, and target separation to new heights. In navigation, chartplotters that blend the latest in mapping and boat positioning tools with cutting-edge sonar bring even more electronic wizardry to the table.

3-D Sonar

Sonar has helped anglers find fish and explore structure ever since Lowrance introduced its iconic "little green box" in 1957. Since then, a steady stream of advancements from a number of different manufacturers have enhanced our view beneath the surface and expanded our understanding of fish location and behavior.


Collectively, the Lowrance StructureScan 3D Transducer and module yield three-dimensional views of the underwater landscape.

The latest twist delivers three-dimensional imagery. A pair of companies—Garmin and Lowrance—staked claims to this new frontier, rolling out 3-D products capable of displaying returns like you've never seen before. Not only are the images crisp, detailed, and accurate, they're presented in a manner that helps anglers understand the world beneath the waves by putting the boat, fish, and structure in an easy-to-grasp perspective.

"The ability to see fish, structure, cover, and boat position in a three-dimensional manner answers critical questions even veteran anglers have when interpreting sonar returns—such as, 'What am I seeing, how far is it off bottom, and where is it in relation to the boat?'" says sonar expert Scott Glorvigen.


"The latter gain is perhaps the biggest victory of all," he says. "Seeing a 3-D view of precisely where fish and structure are relative to your position raises situational awareness, and makes it much easier to place your boat and baits accordingly."

Garmin's Panoptix "All-Seeing Sonar" relies on multi-beam transducers stoked with phased-array sonar technology to scan ahead, behind, below, and beside the boat, and then displays the returns the micro-second they come in.

Dan Bartel, VP of Garmin's worldwide sales, was beaming over the product launch in 2015. "We believe it revolutionizes the way anglers use sonar," he says. "Never before have anglers been able to see all around their boat in real time."

The system includes a pair of transducers and several different viewing options. Geared to looking ahead from the bottom or lower shaft of your bowmount trolling motor (but available with a transom mount as well), the Panoptix Forward Transducer offers LiveVü Forward and RealVü 3D Forward modes.

LiveVü relies on single-ping updates to create video-like, moving images of fish swimming toward or away from the boat. You can even watch your lure throughout the retrieve, and hold your breath as fish move in for the attack. RealVü digitally scans the neighborhood to produce 3-D images, and you can adjust scanning rates to control the amount of detail provided.

The transom-mounted Panoptix Down Transducer offers similar views of what's beneath the boat—with an extra twist. In addition to LiveVü Down and RealVü 3D Down modes, which yield similar returns as their forward-scanning counterparts, you get a RealVü 3D Historical option. This mode produces a wealth of sonar intel, scrolling through data as the boat moves along to reveal everything that has been scanned, top to bottom, displaying bottom contours and fish in three-dimensional color returns.

Garmin 7600 Series

Both the forward- and down­scanning transducers have an internal Attitude Heading Reference System sensor, which continuously adjusts sonar beams to compensate for boat motion. They're compatible with Garmin's GPSMAP 7400/7600 series, GPSMAP 8000/8500 series, and GPSMAP 7x1, 8x0, and 10x0 series chartplotters, as well as the echoMAP 70s and echoMAP 70dv.

Not to be outdone, Lowrance unveiled its own three-dimensional offering in 2015—StructureScan 3D. This new imaging system quickly scans the underwater landscape to create high-resolution, extra-wide, 180-degree 3-D views, which are viewed on a Lowrance HDS Gen3 display in conjunction with a Side-Scan 3D Skimmer transducer and StructureScan 3D module. It offers multiple viewing options, including enhanced DownScan Imaging and StructureScan HD options.

While virtual point-of-view angles are eye-openers for anglers lacking 3-D, the system's ScanTrack pan-tilt-rotate control further increases perspective. "It basically lets you rotate the boat on-screen for a 360-degree view of what your sonar is trying to show you," Glorvigen says.

"Additional functions make it easier to see cover, suspended fish, and even small but important structural features such as tiny rockpiles and inside turns," he adds.

The Vertical Depth Enhancement feature highlights vertical drops and critical contour changes, while SelectScan automatically shades fish-holding cover and suspended targets in the water column in unmistakable contrasting colors.

"StructureScan 3D's Leading Edge scanning reference also reveals exactly where your sonar beams are sounding," says Glorvigen. That's valuable information, considering the unit scans a 600-foot swathe port and starboard in one pass. "Such coverage is an asset when you're looking for fish in open water on large lakes," he says. "It dramatically reduces search time."

No matter which type of 3-D system you choose, Glorvigen says it promises to change the way you fish like no technology before it. "You start to approach fishing with a spot-and-stalk attitude similar to hunting," he says. "Instead of running your boat over the fish and hoping you don't spook them, you scout from a distance and plan your presentation accordingly."

He says that 3-D sonar also helps determine locational trends, such as which way a school of fish is headed. "For example, I was using StructureScan 3D on a Minnesota lake and marked a group of walleyes hugging a breakline," he explains. "When I made two more sonar sweeps, I could tell they were migrating along the structure, while gradually heading down the break into deeper water. Such insight proved helpful when planning trolling passes to intercept the wandering 'eyes, without spooking them."

CHIRP technology adds another twist to the sonar scene. Short for "compressed high-intensity radar pulse," it scans a broad range of frequencies, firing off long-duration "chirps" that typically sweep from around 50 to 83 kHz up to 200 kHz.

Such high-octane, broad-spectrum beams paint a remarkably clearer picture than traditional sonar, which relies on short bursts of single- or dual-frequency ultrasound. "Top traditional sonar units do a great job, but there are still trade-offs," Glorvigen says. "Crank up the sensitivity and clutter increases. Dial it back and lose detail. With CHIRP, you get improved sensitivity without added clutter. Noise rejection increases while target separation goes through the roof."

In practical terms, such gains allow anglers to spot fish tucked tight to bottom, holding in cover, or lurking inside or below dense schools of baitfish. "You can even identify individual fish within a school," he says. "When you're over a cloud of crappies, you can actually separate them all out, zero in on the largest fish in the group, and target them."

So sensitive is CHIRP, he contends it allows you to accurately predict what type of fish are appearing on screen. "Line width largely reflects fish size, but if you combine that information with subtle details such as how a fish moves and the margins of its return, you can begin to see the difference between sunfish and crappies or perch, and tell walleyes from pike or bass," he says.

Similarly, Glorvigen says CHIRP reveals much about a fish's mood, as well as how it responds to various jig strokes. "On a scrolling display, traditional sonar provides a great history of how quickly a fish moves through the water column and reacts to different cadences," he says. "CHIRP gives you an even better idea of the fish's attitude and responses to presentational adjustments."

Manufacturers embracing CHIRP include Garmin, Humminbird, Lowrance, and Raymarine. Examples include Garmin's new GPSMAP 7400xsv and 7600xsv series multifunction displays, which offer traditional HD-ID sonar and true-dual 1kW CHIRP, plus CHIRP DownVü and SideVü options. The new units come in 7-, 8-, 10-, and 12-inch sizes, and along with high-powered sonar, have full pinch-to-zoom touchscreens and built-in 10Hz GPS for lightning-fast position tracking. Other amenities include built-in Wi-Fi and premium basemap choices.

Lowrance's Elite-7 and Elite-5 CHIRP Series displays are equally impressive. An extension of Lowrance's widely acclaimed HDI lineup, the units are available in sonar-only and sonar-chartplotter versions.

Elite CHIRP units use affordable Lowrance HDI Skimmer transducers capable of hitting low, medium, and high CHIRP sonar ranges and displaying two user-selected ranges simultaneously, so you can dial in which best fits the conditions at hand.

In addition to CHIRP, all feature DownScan Imaging and single-frequency Broadband Sounder technology, dispensed via either an 83/200/455/800 kHz or 50/200/455/800 kHz Hybrid Dual Imaging (HDI) transducer. High-resolution, full-color displays with multi-window options are also standard.

Elite series sonar-plotter combos wield the navigational wallop of a built-in GPS antenna, detailed mapping options, and the hydrographic map-making power of Insight Genesis.

Humminbird's CHIRP lineup includes the ION and ONIX powerhouses, which also pack the punch of 360 and Side Imaging, Digital Signal Processing, i-Pilot Link capabilities, and more. Some units also incorporate DualBeam PLUS SwitchFire.

Raymarine's Dragonfly family has been expanded to a fistful of models that deliver the down-scanning imagery of big-vessel ClearPulse CHIRP sonar to smaller craft. As a bonus, dual dedicated channels let you see fish with traditional sonar views, while simultaneously scanning photo-like images via a high-resolution DownVision display.

Other notable Dragonfly features include dual-beam CHIRP transducers (a 60-degree fan beam for DownVision, plus a 25-degree beam for marking fish), built-in 50-channel GPS sensor, Navionics cartography, optically-bonded, backlit display, and user-friendly ­Uni-­controller interface.

Dragonfly PRO models also offer built-in Wi-Fi so you can stream sonar data to smartphones and tablets using Raymarine's Wi-Fish mobile app.

Fishing Sonar Newcomers

Other notable entries in the electronics market include Humminbird's vaunted Helix 7 Series, which captured "Best of Electronics" honors at the American Sportfishing Association's annual ICAST trade show. Comprised of five models built to allow anglers to choose functions that best fit their styles of fishing, the Helix 7 line features an easy-to-use X-Press Menu System keypad control and 7-inch color TFT display.

The family includes the Helix 7 Sonar, which offers down-viewing Switchfire Sonar, along with the ­widescreen-format Helix 7 DI, which is designed for viewing multiple windows simultaneously; plus versions of each enhanced with a GPS chartplotter. The clan is completed by the Helix 7 SI GPS, which offers an arsenal of sonar and mapping weapons, including Side Imaging, Down Imaging, and SwitchFire Sonar.

Vexilar FL-22

Back By Popular Demand

Finally, in the "too good to let go" category, Vexilar is bringing back the FL-22. Released in 2012, the shallow-water flasher features 10-foot ranges that let users match output pulse length to specific depths to get the best resolution and most detail possible in each zone.

"For two seasons, the FL-22 was a great seller, but when Vexilar introduced the FLX-28, we pulled it from the market," says the company's Tom Zenanko. "That was a mistake, as we misjudged the following the FL-22 had generated. Popular demand brought it back and sales have been amazing."

Other admirable features include a low-power mode that shines for spotting fish hunkered down in thick vegetation; 6-foot Bottom Lock for open-water use; and night mode.

As we close the curtain on our rundown of new technology, the FL-22 story is a timely reminder that many manufacturers' product lines remain rich in time-tested units that offer world-class sonar and mapping. You might not see them in the new product headlines, but they're powerful allies nonetheless in our quest to better understand the underwater world.

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