By Vernon Summerlin
Not since peanut butter and jelly have two things gone together so well. Maps and depth finders are a combination every serious angler employs. The term electronics is not a succinct one but it has become the buzzword that stands for depth finders of all sorts. Many of you have other electronic devices and accessories to aid you in determining when, where, and how to locate fish. Oxygen and pH meters, thermometers, GPS navigational systems, radios and telephones to contact other anglers, and trolling motors all have electronic components and could be considered part of your “electronics” arsenal.
Depth finder is a term that stuck with me years ago but some people call the electronic wizards by other names such as depth sounders, fish finders, flashers, graphs, sonar, and so on. I first became aware of depth finders in the 1960s. Back then flashers were the rage.
Flashers are still used but mostly as an in-dash device to show you the bottom as you speed along the lake. This piece of electronics is a clock face with a light showing up at the 12 o’clock position to indicate the surface and a moveable light to indicate the bottom and objects in between. The paper graph was the next depth finder into anglers’ boat. It was the cat’s meow. Its sharp definition of the bottom depicted by a gray line (or white line), the inverted Vs representing fish (even if they were only six inches off the bottom) and an almost true picture of brush, trees, and rocks were printed on paper to become a permanent record. This was and still is an excellent but expensive piece of equipment.
The paper graph required much more attention than the simple flasher. Paper and toner (ink) had to be restocked as well as cleaning the carbon from inside the chart maker. This, however, was a small price to pay for the great detail it provided and, most importantly, the fish it located. Then came the liquid crystal graph (LCG), recorder (LCR) or display (LCD) with an ever-changing image like the paper graph. But it has no paper to move across the front or to replace (no permanent record either), no toner and no lights to interpret. The next generation of electronics was a boon and a blessing.
An LCG is easy to read and maintain. It works at high speeds and many have a variety of programs, including 3-D pictures. Several generations of LCGs have passed with improvements but the basic picture is the same. About the time LCGs came along so did the video screen. Not much different from your TV screen, it offered clear pictures below the surface comparable with paper graphs and some units could provide print outs. Some had colors representing signal strengths. These units are expensive and haven’t caught on with freshwater anglers.
Among the later generation of depth finders is the Sidefinder by Bottom Line. This innovation lets you see what is between you and the bank by operating horizontally. There are even portable units for bank anglers. The one thing all these devices have in common is the transducer. This is the sending and receiving unit. The transducer sends out a constant sound wave that is reflected by the bottom and objects in between. The period of time between sending and receiving is translated into flashes of lights on a flasher, dark pixels on a LCG or lines on a paper graph. The strength of the returned signal will show up as a thin to thick line of light on a flasher, a small to large area of dark pixels on a LCG or thin to thick, light gray to dark black lines on a paper graph. The transducer is designed to send out signals in a cone shaped pattern and is rated by degrees. A cone angle with a tight pattern may be eight degrees or less and a wide pattern may be 36 degrees or more. A 16- to 20-degree cone works best in most freshwater situations because most of our angling takes place in less than 30 feet of water. If the bottom is flat, your transducer will read a circle and give you one red line on a flasher and a straight line on LCD and paper graphs. The narrower the cone angle, the smaller the diameter pattern will be read.
Heedless to say, the latest generation of computer based graphics is much better than a few years ago and a look at the size of the instruction book lets you know there is a lot more to these units than looking for fish symbols. You can zoom in on certain depth ranges, there is an alarm to indicate shallow water, an alarm to let you know a fish is spotted, a temperature gauge for the surface and many more features to feed you information. Add to this the global positioning system that is available on some units and you can be directed to the exact spot you caught fish last week or last year. But that’s another story.
It takes time to learn how to use all of the features, but lucky for us, most of these units have an automatic function. We turn it on and it’s set up to work without us laying a finger on another button. Electronic depth finders are among the most useful tools an angler can have but the topographic map is another tool that will put you on out-of-sight fish, and I’ll talk about maps in a future article.