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. However, for some lures, speed will noticeably affect the trolling depth.

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.

Rod Tip Height

Enter the Rod Tip Height that is in effect when measuring the line angles. This value is used, with the angle, to determine the length of the unsubmerged portion of the line.

You can use a different rod tip height while fishing. For example, if you intend to use a side planer board, take the measurements for the calibration from the boat with a rod tip height that allows you to see and measure the line angles. Then, after the calibration is complete, use a zero rod tip height in the depth control section to determine the amount of line to deploy behind the board.

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.