Using Fish Finders, Depth Finders,

Chart Plotters and SONAR Units

Fish finders are essential equipment on fishing boats. They range from simple depth readouts to combination units that can include mapping and navigational functions. Costs go up with features and can get into the thousands of US dollars.

In choosing a fish finder, you will need to decide on a budget. Next, consideration must be made to the different types of display formats. Black and white is the simplest with other choices being grayscale (also known as monochrome) and color. Another choice is the display type. Fishfinder displays use LCD or other technologies, with choices based on price.

Several factors determine the effectiveness of the fishfinder. When shopping, consider the following parameters:

  • viewable display size

  • display physical type    (CRT or LCD)

  • display format type (monochrome or color)

  • resolution in pixels

  • single or dual transducers

  • transducer frequency

  • output power measured in RMS

  • temperature probe

  • The chart below may help sort out some of the choices to be made

    Fish Finder Feature



    LCD Display

    typically cheaper
    more waterproof
    less fragile


    CRT Display

    good picture prone to breakage, water damage
    Black and White Display inexpensive no longer produced?
    Monochrome or Grayscale display good picture
    viewable in direct sunlight
    less expensive
    does not differentiate targets as easily as color displays
    Second Generation Grayscale  "Blue Screen" display good picture
    viewable in direct sunlight
    sometimes expensive

    Color Display

    excellent at defining different targets difficult to see in bright sunlight

    Second Generation Color Display

    excellent at defining different targets
    viewable in direct sunlight

    Temperature Probe

    important fish finding tool

    sometimes an added expense

    50 KHz Transducer

    good resolution
    essential for deep saltwater
    narrow beam misses fish
    interference in shallow water

    200 KHz Transducer

    excellent wide coverage poor results in deep water

    50 KHz / 200 KHz Transducer

    best of both types! high initial cost


    Related Information

    Installing Fish Finders

    Finding Shipwrecks, Reefs and Structure with Fish Finding Equipment

    Identifying Various Fish with Fish Finding Equipment