Select the Smartphone option, which will use the smartphone sensors to keep the Line Angle field updated to the angle of the phone with respect to horizontal.

Measure the angle of the line with respect to horizontal with the smartphone. This is a convenient and automatic way to measure and record the angle with no additional equipment or manual data entry.

The figure above shows how this is performed by holding the smartphone (not over the water!) parallel to the line and the boat’s travel motion.  Visually align the edge of the device to the portion of the fishing line evident above the surface of the water.

You do not need to place the smartphone directly on the line to measure its angle. The rod can be deployed in a normal fishing position, and you can hold the smartphone inside the boat, as long as you hold the edge of the smartphone parallel to the line.

While the device and the line are aligned, press the Done button to save the displayed line length and line angle, or the All Done button to return to the calibration page.

Trolling Angles also supports an external device, the Trolling Angles Autocline, to measure line angles.

[expandsub4 title=”Alignment” tag=”h6″]

Align the Smartphone Carefully with the Fishing Line.

To get an accurate angle measurement, it is critical that the smartphone body is parallel with the fishing line.  If the smartphone is not exactly aligned with the fore-and-aft direction of the line, the measured angle of the visible line will be different than the line’s actual angle, and therefore the calculated depth will be different than the lure’s actual depth.

It is not always easy to see the exact alignment of the line, especially when the rod tip is out to the side of the boat.  On a calm day, trolling in a straight line, your line is aligned with the boat, and you can then align the phone with the centerline of the boat. However, if the wind is blowing your boat sideways at all, the trolling line will be at an angle to the boat’s centerline, and you probably do not have a good perspective to see the exact direction.

The Alignment Aid

You can use the graphical Smartphone Alignment Aid while taking measurements. It shows two lines, one representing the phone, and another showing the trolling line.  When the two lines are overlapped, the phone is aligned with the trolling line.  The trolling line direction is deduced from the GPS and the water current correction.  The phone alignment is measured using the phone’s magnetic compass, corrected to true north according to magnetic declination at your location.  The GPS is trustworthy when the boat is moving, but the compass and current correction may not be fully accurate, so use common sense whether to use the aid or to eyeball the phone and trolling line yourself.

The Alignment Aid is enabled or disabled in the Settings/GPS Speed and Alignment page.

The Autocline is always aligned with the trolling line, so the alignment aid is not useful when using the A