Sonar Tactics from Top Captains

Use your electronics to their full potential offshore.

February 23, 2018

If you’ve ever asked a bass ­fisherman for advice, their answer usually sounds something like, “You gotta use a Bug Whacker buzzbait on 14-pound fluorocarbon and crank it with a Winchmaster 7 to get the ideal retrieve rate.” It takes just a second or two before you realize that you got marketing-speak, not pure fishing advice.

But when I dialed up jackpot-winning billfish captains who compete for tens of thousands, sometimes even millions, of dollars and asked them for some sonar tricks to find more fish, I came away thinking they might have just helped me become a better fisherman. And I believe their generosity will benefit each of us in this tell-all unmasking of top sonar tactics.

Capt. Ray Rosher, Miss Britt
Miami, Florida
Electronics: Raymarine eSeries, Airmar B275LHW


When chasing sailfish and dollar bills in South Florida tournaments, Capt. Ray Rosher needs altitude. “I like the elevation, to see the fish and get set up for them,” he says. “That means I’m spending a lot of time up in the tower. My displays have to be bright.”

In 80 feet or more of water, the sailfish he’s targeting are almost always swimming right into the current, not to the right or left but straight into it. Once they are spotted, Rosher keeps an eye on the GPS and sonar.

“I don’t want to lose them, so I need a bright display so I can see GPS coordinates at a glance. I’m also looking at the sonar to tell me the depth and what’s holding the fish there — bait or structure — and I also want to see any bait in bold targets. You can’t take your eyes off the fish for long or you’ll lose them,” he says. He sets his sonar to the white background to maximize contrast “so, in an instant, I can register depth and note the GPS coordinates.


“I do a lot of live-baiting, so I don’t move as much, and marking bait is primary. That’s where the chirp sonar comes in: detail. Threadfin herring don’t always make a heavy mark. They’re not very dense. Cigar minnows don’t make such a bold target either, in spite of their bulk. Sardines are denser though.”

Rosher says it’s not a hard-and-fast rule, and at a recent tournament, threadfin herring were showing up like huge fireballs on his sonar. But the bottom line is that more contrast and detail on a bright screen makes targets easier to identify.

And then, Rosher says, there’s the easy-to-use Lighthouse 3 graphic interface. “I never needed a manual with my Raymarine eSeries,” he says. “It’s very simple to navigate through the controls.” And in tournament fishing, you need both accuracy and speed.

Sonar Tactics from Top Captains
While the new displays are bright enough that a blue sonar background registers well in sunlight, many captains prefer the white background for contrast in any lighting. Peter Milisci

Capt. Jason Roberts, Cool Change
Stuart, Florida
Equipment: Simrad NSS evo2, chirp, StructureScan and 3D sonar

There’s a bit of resistance to side scanning and the so-called 3D sonar systems among billfishermen, but Jason Roberts doesn’t follow the pack: His sport-fisher has both.

“It works best in water under 300 feet, but deeper than that, structure definition begins to diminish,” he says of Simrad’s StructureScan 3D. But he uses it anyway, and for a particular purpose: StructureScan 3D can read sideways out to 600 feet and mark fish at long range. “If you’re running in the opposite direction to the fish, it will show up as a red dot,” he says. “If you’re traveling parallel in the same direction, there’s more sonar on the target and it will show up as a streak.


“I usually run the system on auto mode for this. But, thermoclines show up well on 3D,” says Roberts. “When you see a giant line of ‘stardust,’ that’s the thermocline. Fish tend to hang around it.” Roberts sorts out the fish by turning up the gain and noise-suppression settings.

“If you see a red dot [representing a fish] under the boat, you can rotate the 3D image to look at the target above, below or sideways,” says Roberts. That gives you a great feel for a target’s position in the water column, and that tells you how to present the baits.”

Roberts gets the best image from side-scanning and 3D sonar systems in depths under 600 feet. The reason is the echo takes a relatively long time to return from the widest scan ranges. StructureScan 3D can also paint bottom structure down to 600 feet, and to get the best image, he likes to run the scroll speed up to about 50 percent. For wreck-fishing, the 2D view is the next best thing to dropping a GoPro down there.

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Capt. Greg Eklund, Cloud Nine
Islamorada, Florida
Equipment: Simrad NSS evo3, Airmar R599, StructureScan

Greg Eklund likes the Airmar R599LH transducer for its wide-angle scan cone — up to 23 degrees in low-frequency range — and its ability to operate on two frequency ranges simultaneously. With a low-kilohertz chirp frequency on one window, he can look deep and spot individual baits at great depth. He splits the screen to show the high-frequency chirp channel next to it. “This setup really works for me when I find bait on the Airmar R599LH. The high-frequency chirp mode of 130 to 210 kHz covers 1,500 feet of bottom in 210 feet of water. Low chirp goes deeper and still gives perspective on bait between 300 and 500 feet. I can work a single swordfish in bait with that setup,” he says. Eklund’s NSS evo3s are all networked together, so he can see the same information whether at the bridge or in the tower.

Eklund finds StructureScan’s wide beam is most efficient out to 300 feet wide and down to 200 feet. “With it, you can track baitballs and see where the fish are on it, and circle them like you’re tied to them on a string,” he says.

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Capt. Nick Stanczyk, Broad Minded
Islamorada, Florida
Equipment: Simrad NSS evo2, Airmar 599 3 kW

As one of the top swordfish captains in the Florida Keys, Nick Stanczyk depends on low-frequency chirp to find bait and quarry. “It’s kind of cool to mark a swordfish in 1,500 feet or more,” he says. “I turn the gain and sensitivity up as high as possible without interference and clutter — and set my scroll speed to medium. I’ll turn up time-variable gain too.” Auto mode? “I don’t use it,” he adds. “And when I’m marking clutter, I dial it down.”

Aesthetically, he likes a blue ­background on sonar and thinks the new screens are plenty bright to carry it off, but like most captains, he prefers a white background screen for contrast.


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