Find your velocity made good toward or away from the wind, and the optimal upwind and downwind angles your boat's polar predicts for the current wind speed.
Your VMG (toward the wind)
4.2kn
Optimal Upwind VMG
5.0kn
at 40° TWA, 6.5 kn boat speed
Optimal Downwind VMG
4.7kn
at 140° TWA, 6.1 kn boat speed
VMG is the part of your boat speed that actually counts toward (or away from) the true wind direction — the rest is speed spent going sideways to it. Sailing closer to the wind points higher but slows the boat; bearing away speeds the boat up but points worse. The optimal angle is wherever that trade-off peaks, which is why racing polars target a specific angle rather than the closest one the boat can point.
Optimal angles are read from a generic cruiser polar and a nearest-knot match to the entered wind speed — a real boat's numbers will differ. Not a substitute for your boat's own polar or calibrated instruments.
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