The bottom section of the Calibration screen is the heart of the calibration, with the line length and angle pairs that define the geometry of a depth curve.

All angles of a calibration must be measured with the same speed and rod tip height, as entered on this panel.

Trolling Speed

Enter the desired trolling speed into the Speed field in the Angle Measurement section.

For a diving lure, the trolling speed does not usually greatly effect the trolling depth, because the drag and line lift forces are balanced by the lure’s dive force as velocity changes.

For a sinking lure, weight remains unchanged as the drag and line lift forces increase as velocity increases, so that the calibration data is valid only when the boat is trolling at the same speed that the measurements are taken. Be sure to maintain the same boat speed for all measurements of the calibration, and be careful not to change the boat speed field inadvertently. Trolling Angles does not adjust for differing trolling speeds.

Rod Tip Height

Enter the Rod Tip Height that is in effect when measuring the line angles. You can use a different rod tip height while fishing. This value is used, with the angle, to determine the length of the unsubmerged portion of the line.

Measurements

The angle measurement at each line length reflects the average of one or more actual measurements at that length.

To add measurements for a new line angle, select the Add Measurement + button.

To add or modify measurements for an existing line length, select the details chevron icon on the right of the measurement.