Velocity Made Good (VMG)

Velocity made good is the component of a boat’s speed projected onto the straight line to the wind or to the next mark. Because a sailing yacht cannot sail directly into the wind, beating to windward at an angle can put it upwind faster than the fastest reachable speed aimed straight up; the optimum upwind and downwind angles are read off the polar. Tacticians steer to the heading that maximizes VMG, and the figure is the standard measure of upwind and downwind efficiency in racing.