The wind you feel on a moving boat, the true wind combined with the headwind created by the boat's own speed.
Apparent wind is the wind as it is felt and measured on board a moving boat. It's the sum of two winds: the true wind blowing over the water, and the headwind your own motion creates. Stand still and the two are the same; get moving and the apparent wind shifts forward and changes strength.
How it behaves
- Upwind the boat's headwind adds to the true wind: the apparent wind is stronger than the true wind and comes from further ahead.
- Downwind the boat's speed is subtracted: the apparent wind feels lighter than it really is, a classic trap when deciding whether to reef before turning upwind.
- Except dead upwind or dead downwind, the apparent wind always comes from further forward than the true wind.
Where it appears
Sails are trimmed to the apparent wind, and the wind vane on the masthead measures it: AWA (apparent wind angle, relative to the bow) and AWS (apparent wind speed). Wind instruments then calculate the true wind from it, using speed through the water. More in the guide true vs apparent wind.
Manta does this for you
Plotter data on your iPhone over WiFi
Connect your plotter or a WiFi gateway, and Manta shows your instruments live and records wind, depth and speed through the water on every trip.
