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Garmin Fishfinder Tranducers: Worthy Fishing Companions

written by: Daniel P. McGoldrick•edited by: Michele McDonough•updated: 5/29/2009

Garmin Fishfinder Transducers are the ultimate non-human companion for your fishing expeditions on a boat. These devices combine Global Positioning System technology with the ability to determine and display on a digital screen where fish are when traversing any body of water. Find out more below.

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    How Does Sonar Work to Find the Fish on a Garmin?

    A transducer, in general, is any kind of device that converts energy of one type into energy of another type. What we’re essentially talking about here can be explained as converting the presence of the fish that is within the parameters of the fishfinder’s cone of detection, under the boat, to a digital facsimile of the fish on the display reader board topside. The Garmin Fishfinder display is fastened next to the steering wheel so the boat operator can maneuver the boat to optimize the chances of catching the fish which is, of course, the object of this technology. Knowing where the fish are down there doesn’t guarantee you’ll catch fish, however. You’ll still need human ingenuity and fishing skills to land them no matter how easy the machines are making it these days.

    All fish finders operate by using Sonar (an abbreviation of SOund, NAvigation and Ranging), the same technology developed for submarines to navigate in deep water during WWII. If you’ve ever seen a movie about submarines, you’ll recognize sonar as that intermittent but constant “ping" noise. Sonar uses sound waves to determine where objects are in the water, just like a bat uses sound waves to locate and eat flying insects and to keep from crashing into trees and buildings unceremoniously.

    Sonar emitted from the transmitter component of the fish finder travels downward from the boat to the ocean, bay, sound, marsh, or lake floor like the cone-shaped beam of a flashlight. So the beam, or sound wave, sent from the fish finder source becomes an increasingly larger wave in every direction as it travels away from its source. Anything that the beam hits, hopefully a fish, gets bounced back to the fishfinder through the transducer to be converted back to an electrical impulse in order to appear on the screen in the symbol of a fish.

    The fishfinder approximates where the fish are by measuring the amount of time between when the beam was sent out and when it registered the hit. In this same manner, the fishfinder can tell you how far down the bottom is, too, because it always bounces the beam off the bottom. The readout constantly tells you how deep the water is and what kind of structure is down there, like the rocky habitat some fish like to feed in, for instance. These are critical components for both the safety of your boat and in finding where the fish like to congregate and conspire to elude you.

    Garmin Accuracy and Innovation Leads You to the Fish

    Traditionally, the boat would have to be right on top of your prey but with advances in technology these Garmin fishfinders allow you to see what’s off to the side of the boat too by expanding that cone of detection. Increasing the coverage increases the price. The high resolution display screens have come a long way also and resemble nautical charts and decent looking maps. Even the relative sizes of fish or schools of fish swimming nearby appear on the readout. Since you are linked to a satellite, the mapped shorelines are displayed as well. In days of old, fishfinders resembled something rather lame like a blipping Atari video screen.

    The Garmin features technology called Ultrascroll™ which means the display keeps up with your speed by constantly refreshing to maintain the best accuracy of what you’re passing over. That’s great for trolling, a highly productive means of fishing for Marlin or Tuna. Incidentally, Garmin makes plenty of models for freshwater and the shallows you’ll likely find there as well. These are usually smaller and more compact units depending upon the type of freshwater you’ll be fishing. The newer models of Garmin Fishfinder Transducers are far more user friendly with less buttons and more intuitive applications. Convenient alarms are built in, sounding off in extremely shallow water or when your fishfinder battery is running low.

    The Garmin Fishfinder on my friend’s boat was extremely useful in fishing for Striped Bass and Tuna off the coast of Cape Cod, in the Vineyard Sound and along the Elizabeth Islands. When the Stripers are making their solo runs in the fall, there’s obviously a whole ocean out there for them to run and the Garmin helps you find them. When they appear on the screen, there is an exciting scramble and call to action in the boat, especially when it looks like a huge monster of fish is close by.

    Not only that, but that is some very tricky sea to operate in and the Garmin’s capability to pinpoint where the rocks were in that shallow water were crucial in keeping the boat out of harm’s way so we could concentrate on fishing. These devices double as excellent navigational aids. Since the display on most models also tracks the coast line when you’re close to shore, you can imagine how helpful that is in deep fog. It also pinpoint’s prominent structures on land such as towers to aid you in navigation when the skies are clear.