Sounder Introduction

The "Furuno Sounder Module" needs to be unlocked to access the sounder/fish finder features.
Note: No Module is necessary to display the digital depth from a NMEA0183 or NMEA2000 sounder. Please refer to the Sensor NavData chapter for more information.

Echo sounders or "fish finder" determine the distance between its transducer and underwater objects such as fish or seabed and show the results on the screen. An ultrasonic wave transmitted through water travels at a nearly constant speed of 4800 feet (1500 meters) per second. When a sound wave strikes an underwater object such as fish or sea bottom, part of the sound is reflected back toward the source. The depth to the object can be determined by calculating the time difference between the transmission of a sound wave and the reception of the reflected sound. The sounder will then display this return ("ping") as one of up to 64 different colors depending on the strength of the returned signal. Sounder pings are represented over time, in a running display moving from right to left as the bottom appears beneath the transducer.

Most of the sounders on the market can operate at multiple frequencies (usually "Low" and "High"). The frequency of the sound waves created by the transducer impacts the type of reflected returns. Higher frequency sound waves, such as 200 kHz, do not penetrate the water deeply, but they return greater detail from the items they contact. For this reason, the Sounder in 200 kHz frequency is great for fish detection. However, transducers are rarely able to penetrate deeper than 600 feet in 200 kHz mode. Lower frequency sound waves behave in the opposite way. They offer much deeper depth penetration, but provide less detail from objects they contact.

TimeZero is compatible with the following Furuno Ethernet sounder:

  • DFF1: Black Box 600W/1kW Dual-frequency 50/200 kHz

  • DFF3: Black Box 1kW/3kW Dual frequencies between 28 and 200 kHz

  • DFF3-UHD: Black Box High power 2kW/3kW Truecho Chirp™ network Fish Finder for NavNet TZtouch3.

  • BBDS1: Black Box 600W/1kW Dual-frequency 50/200 kHz with bottom discrimination (*)

  • DFF1-UHD: Black Box 1kW Broadband "CHIRP" Dual frequencies (50 kHz +/- 20 kHz, 200 kHz +/- 25 kHz) with bottom discrimination (*)

  • TZtouch2 & TZtouch3 Internal Sounder: 600W/1kW Dual-frequency 50/200 kHz sounder integrated to the NavNet TZtouch2 &  TZtouch3 MFD with bottom discrimination (*)

  • FCV-1150: Standalone 1kW/3kW Dual-frequency 28/200 kHz

(*) The Bottom Discrimination is only available with selected transducer models. Make sure to contact your Furuno dealer for transducer compatibility.