How fast you are actually getting upwind or downwind, the part of your boat speed that brings you toward your goal.
VMG (velocity made good) is the part of your speed that brings you directly toward where you want to go. Sailing close-hauled at 6 knots doesn't take you upwind at 6 knots: much of that speed goes sideways. VMG is what's left in the direction that counts.
Calculation
VMG = boat speed × cos(angle between your course and the direction you want to go)
- Upwind VMG compares your course with the wind direction: how fast you climb toward the wind.
- Downwind VMG does the same with the wind behind you.
- Toward a waypoint the same idea is often called VMC (velocity made on course).
Why it matters
Pointing higher shortens the distance but slows the boat; bearing away is faster but sails further. The best VMG lies in between, at a different wind angle for every wind strength. That's exactly what a boat's polar diagram shows, and why racing sailors watch VMG more closely than speed.
Manta does this for you
Sailing polar diagrams from your own trips Pro
Manta builds your boat's polar diagram from the trips you sail and shows how well she performs on every point of sail.
