Matt Wood, national sales manager at Furuno USA, learned about sonar on the job, facilitating joint ventures with the Russians in the 1990s. It probably helped that he speaks Russian. He’s seen a lot of changes in the industry and still gets excited about innovations with sounders and sonars. “The transducers are changing,” he says, speaking from his home office. “And the equipment is changing. But what’s changing radically in the last two or three years is the way we visualize the information. What people like now are our PC sounders and sonars, and these are scalable.” Furuno has systems for almost any application, from small recreational fishing vessels to freezer trawlers.

At the top of the scale is Furuno’s F3DS software combined with the latest FSV25 color scanning sonar. “It offers a 3-D view 360 degrees around the vessel, from the surface to the bottom,” says Wood. “We’re selling mostly to the big trawlers in Europe. They can look directly ahead and to the side. If they see fish ahead but they slip to the side before the boats gets there, the captain can steer onto them.” He notes that more economical systems like the DFF3D can benefit bluefin tuna fishermen like those off the coast of Maine.

The new Furuno sonar combination has evolved from advances in transducer and PC processing capacities. “We’re leveraging the speed of processors and more sophisticated graphics cards,” says Wood. “That’s what enables us to do this.” He notes that conventional multifunction displays don’t have enough memory to handle all the information the new transducers can collect. “Young captains have grown up with a PC mouse in their hand,” says Wood. “For them it’s easier to manipulate data with a PC.”

The data comes from the transducer. And with multibeam transducers, the data harvest varies. Furuno’s DFF3D for example can be purchased for under $3,000 and has eight elements, each one sending pulses at various frequencies and directions. The WASSP transducer often used with the Furuno TimeZero bottom builder program, has 112 elements. “Each one has two detection points,” says Wood. “That gives you 224 detection points and more detail.”

The information coming from these new systems is helping fishermen understand fish behavior, Wood believes, enabling greater operational efficiency. “Fishermen know where the fish are, but they don’t always know why,” he says. “For example a herring fisherman, Alan Ottness, started creating pictures of the area he had fished for years. His bottom sounder showed him variations in depth, but now he can see the entire area. He calls it craters of the moon because there are all these craters there where the fish concentrate.”

Wood notes that Furuno is not alone. “To give them their due, everyone is depicting 3-D imaging now, Simrad, Olex, iXblue — the French company.” Simrad Introduced its SN90 sonar last year. The SN90’s forward-looking fixed transducer eliminates the risks associated with large through-hull fittings associated with movable transducers. With recent upgrades, the system remains a milestone in sonar development.

Mike Hillers, general manager for Simrad Fisheries, points out that with transducers there are two main issues for maximizing performance: the first is matching to the transceiver, and the second is efficiency. “For matching, the key is frequency of course,” says Hillers. “A 38kHz transducer, for example, must go with a 38kHz transceiver, but with the advent of broadband (CHIRP) systems, it is even more important. A mismatch can cause the destruction of components, usually the transmitter.”

In terms of efficiency, Hillers points out that it’s a matter of power — 1,000W, 2,000W, etc. “This is a measurement of the amount of power coming out of the transmitter and is not an indication of system performance,” says Hillers. “One of the keys to system performance requires an efficient transducer because the energy (electrical power) coming from the transmitter is being converted to sound energy by the transducer. An inefficient transducer or one not matched to the transmitter will not send out enough sound to justify the high power of the transmitter.”

Hillers notes that construction of transducers affects their performance. “There are three basic transducer construction techniques,” says Hillers. “Wire-wound either ferrite or nickel — only in use today with low-frequency, high-power systems.” According to Hillers, most transducers today are ceramic, consisting of single or multiple ceramic disks that receive the power and resonate physically to generate sound energy. While this style of transducer has traditionally been used for a single frequency, it is now being used in CHIRP systems (although transducers designed to CHIRP give better performance over a wider frequency range).

“This style of transducer at lower frequencies is usually made with multiple ceramics,” says Hillers, pointing out that these ceramic modules consist of a heavy mass — bronze — then the ceramic and then a lighter mass — aluminum. This configuration directs the sound out the face of the transducer, whereas a ceramic on its own will send out sound in all directions.

“The third and newest style of transducer is a composite ceramic transducer,” says Hillers. “A block of ceramic is cut into staves and reassembled. These composite transducers have the best performance in a broadband (CHIRP) system.”

Transducer size, Hillers points out, is related to the frequency, the beam angle, and the power handling capability. “A small ceramic cannot physically take a huge amount of power. A bigger transducer is generally a lower frequency,” he says.

The French company iXblue has its own version of a 360 degree 3-D sonar, called Seapix. According to the company, Seapix is a complete, standalone system combining an acoustic sensor with its own data processing system for analysis of the marine environment. The company claims that Seapix can assess 20 times more fish and seabed area than classic multibeam sonars.

“For the first time in the fishery market, a volumetric 3-D sonar provides realistic fish evaluation and full ecosystem description. Skippers can now select fish species and improve both profitability and sustainability,” says the company’s literature.

Features of the Seapix system include: volumetric biomass assessment with 120° x 120° water volume coverage, fish species discrimination, and bathymetry mapping and seabed analysis. The iXblue system offers fishermen real-time descriptions of whole ecosystem and fishing action, all merged into one navigation and charting system.

According to iXblue, Seapix offers the advantages of advanced sounders and sonar, creating a volumetric visualization of the underwater environment, much like Furuno’s system.

To overcome the challenges involved in delivering such a carefully targeted product for the fishing industry, iXblue’s engineering teams homed in on groundbreaking technological solutions. Seapix generates one or more scan swaths along or across the vessel axis, thus providing total three-dimensional coverage of the water column, a bathymetric profile of the seabed, and identification of sediment type. Its transducer generates several simultaneous multibeam transmissions and acoustic processes to yield high quality measurements of the marine environment.

iXblue vaunts Seapix as one of the easiest sonar systems to install. The “all in one” sonar housing concept dramatically eases vessel arrangement and cabling constraints.

The sonar antenna unit (SAU) includes both acoustic arrays, electronic boards and processing unit, and a 3-D motion sensor for stabilization. The SAU can be installed in conventional downward-looking configurations, or as forward-looking or side-looking, depending on the fishing applications. The Seapix SAU is very compact and can be installed in the same way as a conventional sounder (no moving parts).

Most fishfinder manufacturers are building on advances in transducers, particularly CHIRP, the technology that allows transducers to transmit and receive across a range of frequencies. Technology is revealing in greater detail the once invisible world below the waves. As transducers and processing capacities improve, fishermen are getting a whole new view of where the fish are.

“CHIRP actually came from the military in World War II,” says Craig Cushman, director of marketing at Airmar Technology, a major developer and manufacturer of transducers. “Since 2011 we’ve been using it to build bandwidth into transducers. Instead of one ping coming in, you have a hundred. And the companies like Simrad and Furuno are building the receivers that can compress this into imagery.”

According to Cushman, nothing has changed the industry as much as CHIRP, but the company’s primary goal is to improve transducer efficiency. As noted by Hillers, efficiency is the key to getting information to the receivers. “Efficiency amounts to transmitting power into the water and reducing ringing,” says Cushman. “The ringing is the Q-value, the lower the better. Our mission is to get as much power as we can into the water and get it back.”

Airmar builds transducers for Simrad’s side-scan sonars and Furuno’s DFF3D systems, as well as for Notus, and its offshoot company, Marport. “We have something coming up with Marport,” says Cushman, “But we can’t talk about it yet.”

While the basis of the new technology is not so new, companies are bringing costs down to put advanced machines on all sizes of boats, and fishermen are using them to reduce bycatch and improve performance. “They’re seeing a whole new world of electronic information out there that can help them,” says Cushman. “And more are starting to use it..”

Paul Molyneaux is the Boats & Gear editor for National Fisherman and author of “The Doryman’s Reflection.”

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Paul Molyneaux is the Boats & Gear editor for National Fisherman.

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