InstrumentAid - Polar Plot Window with Optimized Tacking Data

The optimized tack angles and percentage time on each tack is computed from performance polars and the desired user specified course.  The dashed green line shows the ideal wind angle for a starboard tack, and the dashed red line shows the ideal wind angle for a port tack.

In the sample shown here, the Waypoint course is 80 degress, and shown by the blue arrow.  The boat is sailing on a starboard tack at a Heading of 40 degrees.  For these sample conditions the optimized tacking data is composed of two parts:

• Starboard tack of 48 degrees for 60% of the time, as shown by the green arrow
• Port tack of 132 degrees for 40% of the time, as shown by the red arrow

The predicted velocity made good is 6.1 kts.

The green arrow indicates that the boat should turn 8 degrees to starboard for optimum performance.  By heading up the boat will slow down on the starboard tack, but make better velocity on the desired course.