Fishfinders

Whenever you go fishing you have two choices: You can wait patiently and hope that the fish find your bait, or you can take the initiative and go find the fish. For those Type A fishermen, the only way to accomplish the latter is with a fishfinder, a marvel of technology that lets you "see" whatever's swimming beneath your boat. Fishfinders, like computers, have been evolving quickly and now give incredible details of bottom contour and everything in between. George A. Smith, a BoatUS Member and offshore fisherman from Virginia Beach said in a letter to BoatUS". . . comparing my old fishfinder to my new one is like comparing an AM radio to a stereo television." He said that he's been consistently impressed with his new fishfinder's many features, as well as its detailed accuracy under water. As the quality of fishfinding technology improves, the list of features available continues to grow. Take a look at the information below; it will help you select the fishfinder that is best suited for your type of fishing.

The Fishfinder's "Eye" Under Your Boat

A transducer converts electronic impulses from the fishfinder to sound waves, which travel down through the water at about 4,800' per second, regardless of frequency. When the sound waves bounce off the bottom or a fish, the returning echo is picked up by the transducer, which converts it back to electrical impulses. These impulses are then sent to the fishfinder where they are converted to a picture of the bottom and, hopefully, fish. The higher the frequency of the impulse, the more detailed the resolution will be. For deep sea fishing, a lower frequency transducer may be a better choice, since it can be used at greater depths.

Transom-Mount Transducers

Installed properly, a transducer mounted flush with the transom works well. If it isn't mounted flush, it creates turbulence that will interfere with the signal--you'll see bubbles and not fish. Benefits of using transom-mount transducers include accessibility for cleaning and maintenance, not having to drill holes through the hull, and being able to swap transducers easily if you change fishfinders. Transom-mount transducers work best on outboards; inboard boats typically have turbulence from struts and rudders as well as prop wash. Transom mounts can easily be installed by the average handyman.

Through-Hull Transducers

Through-hull transducers come in two basic styles, shoot-through and drill-through. Shoot-through transducers are made for boaters who can't bear to cut a 2" hole in their hull. The hull must be solid in order for shoot-through transducers to work well, however. If your hull is solid, you will need to make sure the transducer is installed perpendicular to the water. Drill-through style transducers come in hundreds of varieties from plastic to brass. They require that you cut a hole in your hull for permanent installation. Installation is more difficult than with transom-mount transducers, but the benefit is that a through-hull transducer can be mounted on any hull. On planing V-hulls, the through-hull should be mounted aft, on a relatively flat area that won't be lifted out of the water. On curved hulls, a fairing block may be necessary to keep the transducer pointing down (slight angles can be tolerated). For the average handyman, we'd recommend having the yard install a through-hull transducer.

Installation and Maintenance Tips

• Don't trim the fishfinder's transducer cable to fit your boat. If it's too long, coil it. Cutting the cable will interfere with the accuracy of the fishfinder's signal. Some manufacturers supply cable if you need a longer cable.
• Immediately after haulout, clean the bottom surface of the transducer to remove slime and barnacles. If necessary, sand lightly with 240-grit sandpaper.
• Never paint a transducer with bottom paint. Special paints inhibit marine growth without interfering with the signal.
  

Pixels, or picture elements, are like a checkerboard of tiny dots that darken upon receiving electrical impulses, which is how fishfinders form images. The greater number of pixels a fishfinder screen has in it's vertical column, the higher the resolution. If a screen has 100 pixels in its vertical column and you're looking for fish or bottom structure in 200' depth range, each pixel represents 2" of depth (200'/100 pixels). The horizontal row determines how long information stays on the screen before it scrolls off, which is important when trolling and in any split-screen application. More pixels equals a betterr picture. And when the higher pixel count is coupled with a large screen - you can't help but snag a few fish!