True vs Apparent Wind
If you're hanging out at any yacht club bar, reading your instruments or talking about sail trim, then chances are you've heard people talking about things like true wind speed and apparent wind angle. Well what does all that mean anyway? What is True Wind? Imagine you are standing still in a paddock. There is a light breeze of 5 knots coming from the north. This is the true wind speed and the true wind angle or direction. It is the actual speed of the wind as it passes over the land or surface of the sea. It is also the apparent wind as this is the same wind that you are feeling when you are standing still. What is Apparent Wind? Imagine you are still in the paddock with the 5 knot northerly, and you start running north at 5 knots. You are now 'feeling' 10 knots of wind. The 5 knots of true wind, plus the fact that you are running at 5 knots - gives you 10 knots of 'apparent wind'. It isn't actually blowing 10 knots but because you are running that fast in to the wind that is what you feel. If however you run south - with the wind behind you, and you run at 5 knots - i.e. the same speed as the wind, then you will feel no apparent wind at all. Apparent wind is a combination of wind direction and the direction and speed of the moving object. The two winds, the actual wind and the wind created by the motion, are added together and this is your apparent wind. Picture by Richard Loseby of Bella Vita setting off on the #pacificrally2022
