How to Use a Fish Finder

Depth finders, or fish finders, are sonar units that bounce sound waves off the bottom of the lake to determine water depth and the presence of objects between the bottom and the surface. The first fish finder used a rotating diode, while units today use liquid crystal or CRT displays to show the bottom and fish that may be present.

Difficulty:

Moderate

Instructions

1. Mount the transducer far enough away from the engine to avoid radio interference and turbulence. Transducers can be mounted externally, either on the boat transom or on a trolling motor shaft, or internally. If mounting internally in a fiberglass boat, be sure there is only one layer of hull between the transducer and the bottom of the boat, as the sound waves will not travel between air and water.

2. Set the sensitivity control between 75 and 100 percent. This is the most important control to set correctly.

3. Adjust the gray line to between 6 to 12 percent or turn it off entirely.

4. Increase the chart speed to as fast as it will go according to the speed of your boat. Use a faster chart speed when the boat is moving slower and a slower chart speed when the boat is moving faster.

5. Turn off the suppressor feature. The suppressor is designed to reduce noise interference; setting it too high will block out the signal entirely. If you mounted the transducer correctly, you should not have to use the suppressor.