Passage planning

Leeway & course to steer

Given a desired track, boat speed, current set/drift, and wind, compute the course to steer to hold track — including leeway correction.

Desired track & boat

Desired track (°T)

Speed through water (kn)

Current

Current set (°T)

Current drift (kn)

Wind & leeway

Wind direction (°T, where FROM)

Leeway angle (°)

Leeway pushes the boat downwind of where it points, so the course to steer is corrected that many degrees up into the wind. No correction is applied with the wind dead ahead or dead astern.

Result

Course to steer (°T)—

Water track (°T)—

Speed made good (kn)—

Course made good (°T)—

Leeway side—

Can hold track—