Apparently it’s not true… we have been doing it wrong!
When discussing the wind, sailors use two different terms to describe its direction and strength: true and apparent. True wind is what most people would think of when they hear reports of wind speed. If the wind is blowing 5 knots out of the north, the true wind is simply that, 5 knots out of the north. And as long as we remain stationary, that’s all that really comes into play. As soon as we begin to move however, our motion starts to create its own wind. To illustrate that, imagine what you would feel if you were to stick your hand out the window of a car moving 60 miles per hour. Even if the breeze on that day was very calm, you would still feel a considerable force on your hand. That is apparent wind.
Once we begin to move, creating our own breeze, this changes the wind’s effect on our sails. To what end? You could do the math and draw a little vector diagram to figure out the speed and direction of this new wind, referred to as “apparent wind,” or if you have a wind instrument on your boat like most sailboats do, you could just push the button on your gauge to switch the readings from true to apparent, letting the internal computer do that math for you.
Do you think this eagle we spotted cares about
whether the wind hitting his wings is true or apparent?
So why did I say that we have been doing it wrong? Well, although we have been aware of this info since we first took our sailing course, we have always kept our gauge set to read true wind. After quizzing several sailors as of late, it appears as if we’re just about the only ones who do this. “I don’t care what the real wind is. I only care about how it’s hitting my sails” is what one of our friends told us. This makes sense to us of course, so when we have the chance to raise our sails (which hasn’t been all that often in the last few weeks) we have been paying a lot more attention to the apparent wind, instead of just the true readings.
There is one caution about always sailing with your gauges reading apparent wind and it relates to downwind sailing. When sailing with the wind coming from astern, the apparent wind will always be less that the true wind (basically it would be the difference between the speed at which you are moving and the true wind speed). Unaware sailors could get caught with too much sail up if they’re not careful, missing the cue to reef the sails.
Charleston, SC, where we are on route to right now from last evening’s anchorage, Awendaw Creek. We’ll be stopping in Charleston IF we can find a suitable place to anchor. Reports are though that it may be tough to do so. Unlike many cruisers, we are not really “marina people.” If we can’t find a place to drop the hook, it’s likely we’ll be moving on.