Drift Correction

What it does

• Heading and track diverge whenever a current crosses the leg.
• Three numbers — speed, set and rate — are enough for a small-craft correction.
• The tool returns the steer heading and the speed made good over the ground.

How to use it

1. Set is the direction the current flows towards, not where it comes from.
2. Recompute at every sector boundary; a single correction for a whole leg is luck.
3. A drift angle above 20 degrees is a signal to re-time the leg.
4. Keep the vector sketch; it explains the correction faster than the number does.

Safety notes

• A correction assumes the current behaves as published; verify with a transit.
• Never let a corrected heading take you outside the planned corridor.