Basic Instincts

Now more so than ever, anglers have technology on their side with advanced side scanning sonar systems revealing detailed bottom features recently undetected by even the most astute captains. Sure, seasoned salts probing their home turf like to believe they know every nook and cranny like the back of their hand, but this latest technology is really revealing an exciting new world.


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While scanning sonar is beneficial, it takes practice to interpret returns. Nevertheless, with such detail you can count on seeing more of this technology. Photo: Humminbird

Like most modern communication, charting and bathymetric systems, anglers benefit from the Armed Forces as futuristic equipment trickles down the chain of command to the recreational sector. Today, advanced side scanning sonar systems relay detailed underwater imagery with photographic precision and the compact, user-friendly technology is available to the general public at extremely reasonable prices.

Rocks, wrecks and even large fish can easily be identified, offering greater insight into the makeup of an object including its height above the seafloor.

It’s common knowledge that sound travels well in water. The reason for this is because water molecules are so tightly packed. Sonar, an acronym for sound, navigation and ranging, is no new concept with early systems developed during World War I to detect enemy submarines. Basically, by transmitting a sound pulse and calculating the transmission time for it to return to the sounder, the user is provided precise depth. Sonar advanced by leaps and bounds by World War II, with stronger pulses and beams resulting in much greater target definition and acuteness. While initial units were primitive, fortunately much more effective methods of transmitting sound waves and displaying resulting signals have since been introduced.

The latest sonar technology features advanced side scanning capabilities. Humminbird first introduced this trend-setting equipment in 2004 with Side Imaging and Lowrance was quick to follow with StructureScan. Here’s how the technology works. Utilizing a combination of high-tech transducers with intuitive displays loaded with intelligent software processing programs, side scanning sonar shoots a laser thin, ultra-wide fan shaped pulse out at an angle to both sides of a slow moving boat. The returning, well-defined signals translate into crisp images substantially increasing user ability to locate new fishing spots and detect specific bottom contours. Different portions of the beam hit suspended targets and structure with a slight time delay, resulting in shadows. The three dimensional appearance greatly enhances identification and enables users to decipher the exact shape and composition of an object. Rocks, wrecks and even large fish can easily be identified, offering greater insight into the makeup of an object including its height above the seafloor.

While it sounds techy, the precise positioning of transducer elements is what actually gives these advanced units the magic required to produce such clear and crisp images, which can ultimately be displayed on a wide range of different size screens.

As far as distance, users can easily decipher key structures upwards of 150 feet below the surface. Humminbird’s Side Imaging projects up to 240 feet to both sides of the boat, while Lowrance’s StructureScan is capable of scanning 250 feet to each side. That’s a huge swath of water that can be monitored. While bass anglers are going bananas over the technology, offshore anglers may have a gripe with depth limitations bound by physics and properties beyond the scope of this editorial. But don’t think this technology isn’t beneficial in open water. Even if you’re trolling the Gulf Stream 1,000 feet above the bottom you can still detect game fish and bait concentrations below the surface and at a substantial distance to either side of the boat.

While side scanning sonar is clearly the latest and greatest technology available to recreational anglers, standard 2D displays that we’re all accustomed to have been around for a long time and users familiar with traditional sounder displays may find the transition to side scanning units somewhat challenging. While the orientation of a side scanning display can be compared to looking down and through a glass bottom boat, new viewers often don’t understand exactly what they’re looking at. In particular, studying a screen that’s flowing from top to bottom, which is your direction of travel, instead of traditional displays that scroll from right to left.

With side scanning sonar quickly gaining popularity, it wasn’t long before downward-looking scanning sonar entered the scene as well. Humminbird’s Down Imaging and Lowrances DownScan, utilizing the same advanced transducers, produce crisp snapshots of essential bottom features. The resulting images produce a clear picture displayed side by side with traditional 2D readings, with all of the detail of side scanning technology.

The best advice is to use side scanning and down scanning technology simultaneously on a multifunction display. Side scanning reveals wrecks, ledges and bottom contours you wouldn’t have otherwise noticed and once you’re directly on top of these targets, down scanning sonar reveals greater detail and clarity. With the ability to see individual game fish, schooling baitfish and bottom structure in exceptional detail, not to mention real time, anglers willing to explore these new technologies will certainly enhance their ability to stay connected. However lets make sure one thing is clear. While advanced tools will keep you pointed in the right direction there’s no substitution for basic instincts.