GPS

If the GPS switch is turned on, the app will display the actual boat speed, and will show a warning if the current boat speed differs from the calibration’s speed. You may change a setting to determine what percentage speed difference to allow before warning.

Current Correction

The depth of a sinking lure is heavily dependent on the speed of the lure with respect to the water. When there is a significant water current, the speed with respect to the water is different than the speed given by the GPS.

Trolling Angles can show the speed and direction of the rig with respect to the water by comparing the GPS and the water current. This gives you the knowledge to control the boat speed to accurately achieve the desired lure depth when using weighted lines or downriggers in tidal currents and large rivers,

If the current switch is on, the GPS control shows the speed and direction components of three related velocity vectors:

• Speed Over Ground (SOG), as given by the GPS.
• Current, as entered by the user.
• Speed Through Water (STW), as calculated by Trolling Angles.

The depth curve of a trolled line is determined by its Speed Through Water (STW).

Since the Over Ground vector is the sum of the Current vector plus the Through Water vector, the STW is calculated by subtracting the Current from the SOG.

The only trick in this process is to determine and enter the Current speed and direction. You may be able to find the current at certain locations as measured by government current gauges. On a calm day, you can let your boat drift as you read the speed and direction from the GPS.

Or, you can use the Trolling Angles Water Current Gauge!