•Calibrate Water Speed—this appears only if you are using a speed-capable transducer/sensor. Calibration is required to ensure that the water speed shown on your Fishfinder is accurate. The Fishfinder automatically uses GPS ground speed (if available using NMEA input) for comparison on the calibration. If a GPS ground speed is not available, use either your boat’s speedometer reading (not always accurate) or a stopwatch to determine your speed over a certain distance (distance / time = speed). It is recommended that the calibration take place in water having little or no current.

To calibrate the water speed:

1.Use the ROCKER to highlight Calibrate Water Speed, and press ENTER.

2.Bring the boat to a cruising speed. Both the top GPS ground speed and uncalibrated water speed appears at the bottom of the calibration window. Note your top speed, then stop the boat, and press ENTER.

3.By default, the top speed automatically appears in the What was your top water speed? field. If a ground speed is not available, the top uncalibrated water speed is used instead. If the new speed is correct, highlight OK, and press ENTER. If you want to manually enter a calibration, press ENTER on the speed field, enter a new speed, and press ENTER.

Using the Fishfinder 340C > Using the Main Menu

NOTE: If the boat is not moving fast enough or the speed sensor is not registering a speed, a “Boat Is Not Moving Fast Enough To Calibrate” message appears at the bottom of the screen. Check that the speed sensor wheel is moving or safely increase boat speed. If there is a problem with the Fishfinder speed sensor, or if a speed senor is not installed, a “Water Speed Sensor Is Not Working” message appears at the bottom of the screen. Check the connections of the speed sensor cables.

Fishfinder 340C Owner’s Manual