Billowing smoke. Swirling dust and sand. Dancing leaves. Pinwheels, flags, windmills, kites. Ocean waves, sand dunes and snow drifts. The wind is invisible, yet we can see and feel it all around us. It is chilling in winter, a welcome refreshment in summer, and potentially destructive almost anytime.
There is no better place to experience the wind than out on the water in a small sailboat. By definition, a sailboat exists because of the wind. It gathers all its life from the breeze and is helpless when the wind disappears. Sailors put up sails to harvest the energy of the wind, and they take down sails when they are overpowered by its awesome force.
My first Bermuda Race, in 1972, was a good demonstration of the wind's many attitudes. Two days out of Newport, R.I., we were becalmed in the middle of the meandering Gulf Stream. I remember staring incredulously at an ocean as calm as a pond at dusk. We even went swimming! Twenty four hours later, however, we sailed into a near-hurricane, with winds over 50 knots. The millpond had turned into a maelstrom, and we were slamming off the backs of 20-foot waves. The contrast was incredible.
Whether racing or daysailing, getting tuned in to the wind is probably the most important thing a sailor can do. In fact, you must feel comfortable with the wind before you'll ever feel in control of your boat.
There are two aspects of the wind that are important: strength and direction. Before heading out on the water, try to get a good feel for both of these variables. You won't want to go sailing, for example, if gale force winds are expected; this wouldn't help your enjoyment of the sport. You might also want to avoid sailing in a strong offshore breeze until you're confident of your ability to sail upwind -- unless, of course, you've always wanted to make that 10-mile trip to the other side of the bay.
There are several ways to get an idea of wind strength and direction before you head out on the water. The first is simply your own observation. As author Dave Perry once said, "When I wake up and see my mailbox blowing sideways, I get a sudden urge to mow the lawn." The British have come up with a system of judging wind strength on land, called the Beaufort scale. This offers a good way to judge how hard it's blowing by looking at the activity of the trees. Be careful of underestimating the wind this way, however. There will usually be more breeze out on the water than in the seclusion of your own backyard.|
Another way to get an idea of wind strength and direction is by listening to the weather report on your local radio station. Don't put too much faith in these predictions, however, since they're often generalizations bearing little resemblance to reality. When I was sailing as a kid, our local weatherman used to broadcast from the station's airplane while flying over Long Island Sound. We'd be sitting in our boats, totally becalmed, when out of our radios would come a report that the wind was blowing15-20 knots from the south. We used to joke that the weatherman was holding his anemometer out the window of the plane.
A more reliable source of wind and weather predictions are broadcasts by the National Oceanographic and Atmospheric Agency (NOAA). These are continuous weather updates on special frequencies. They provide information such as: "Winds will be south to southwest this morning at 5 to 10 knots, shifting to westerly this afternoon and building to 15 to 20. Wave heights one to three feet on the bay, three to six feet on the ocean. Small craft advisories will be in effect this afternoon and small craft warnings should be heeded after 5:00 tonight. High tide at Long Point at 1:14 pm." This is the kind of information that anyone heading out for a sail really needs to know.
Once you've decided that conditions are satisfactory for sailing, it's time to head out on the water. Here it will be easier to gauge wind direction and strength because you are not shielded by trees or buildings, and you can easily see the wind on the water.
An experienced sailor knows the wind direction at all times. This information is very important for trimming your sails and handling your boat properly. When we talk about wind direction, we mean where the wind is blowing from (not where it's going to). There are a number of ways to determine this.
When I learned to sail, I was taught a method known to old salts as "holding a finger to the wind." To do this, put your forefinger in the water (or in your mouth) to get it wet and then hold it up in the wind. Wherever you feel the most coolness on your finger is where the wind is coming from. I can't say I've used this method too recently, but I think it still works. A more reliable guide, for both wind direction and strength, is simply the feel of the wind on your body. America's Cup skipper Dennis Conner reportedly gets his hair cut very short before major regattas so he'll be able to feel the wind on the back of his neck. This way it's easier for him to sense a change in wind direction or strength without having to look around all the time.
Since we're not all quite as intuitive as Dennis Conner, it's definitely helpful to have a few visual clues to help us determine wind direction. My personal method of choice for determining wind direction is to use ripples on the water. I look toward the wind and try to direct my line of sight so it bisects the ripples (is in line with the direction they're moving). Sometimes I stick my arm out straight toward the wind at the same time, and move my arm until it is perpendicular to the ripples. Then I am pointing at the wind.
I remember iceboating for the first time a couple years ago. Until that time, I could never figure out how iceboaters knew what the wind was doing. It seemed that, without ripples on the water, the wind was truly invisible. That day I learned this was true to a certain extent, but I also learned I could tell a lot about the wind by feeling what it was doing to my boat. This sense of feel is so important in sailing.
There are, of course, many other ways to figure out the wind direction. You can always look at flags (on land or on boats), or smoke that's coming out of a smokestack. Other indicators are telltales, usually made of yarn, that are tied to your boat's shrouds and a masthead "fly" on top of your mast. Some bigger boats even have instruments, connected to the masthead unit, that give you a continuous readout on wind direction and velocity. Unfortunately, that's a luxury you probably won't ever find on a small boat.
A more scientific way to tell wind direction is to let your sails luff completely. Just let your sheets go for a few seconds. The sails will start flapping and will move to a position that is lined up with the flow of the wind. If you look where the sails are pointing, that's where the wind is coming from.
One refinement of this technique is to let your sails flap and turn your boat so the sails are luffing along the centerline of the boat. Now the bow of your boat is pointing toward the wind. This technique is often used by racing sailors who are trying to find the wind direction before the start of a race.
One of the hardest times to tell wind direction is when the wind is so light that you can't see any ripples on the water. Some racing sailors light up a cigarette so they can watch where the smoke goes. I like the idea of blowing soap bubbles and watching where these float. When the bubbles hover in your cockpit, you know you've got a real drifter on your hands!
Knowing (and being able to anticipate) the strength of the wind is very important for both safety and performance. When I was 14, I was sailing my 13-foot Blue Jay home from a race when we were suddenly caught in a 40-knot squall. At that age, I didn't know the wind could blow so hard or that it could come up so suddenly. We capsized immediately and spent 30 long minutes in the water but, fortunately, we were rescued. It's very important to know when a squall is coming or when the wind is about to die for the evening (and make you paddle home). Here are some useful rules of thumb.
1) The key to anticipating the strength of the wind coming toward you is the appearance of ripples on the water. (Don't confuse the larger wave pattern with tiny wavelets created by the wind.) Basically, the closer together the ripples are, the more wind there is.
2) Another sign is the color of the water surface. The darker the water, the more wind there is. The reason for this is that when you have a lot of wind ripples, less of the sky's brightness will be reflected to your eyes. You can often see puffs (dark blotches) moving across the water.
3) If you're looking into the sun, the glare will make it look like there's more wind than if you're looking away from the sun. Also, the breeze looks stronger if you're looking into the wind than if you're looking away from the wind. This is because the back sides of the ripples are less steep and therefore reflect more of the light-colored sky.
4) When whitecaps just begin to form on top of the waves (in an open body of water), the wind is blowing about 12 or 13 knots. Most boats begin to get overpowered around this velocity.
5) Other good guides for wind strength are: a) the action of smoke coming out of smokestacks; b) how straight flags are blowing; and c) how much other boats are heeled.
In the United States, the National Weather Service, a branch of the NOAA, uses a system of signals to warn sailors about high winds and storms. For example, if you see a triangular red flag on the flagpole at your local marina or yacht club, a small craft warning has been posted. This means that wind and sea conditions are such that small boats should not go out. Other signals warn of gale winds and hurricanes. You should definitely know these signals and where they are displayed in your area.
Before leaving this subject, we should mention that wind speeds, like boat speeds, are almost always measured in "knots." A knot is defined as one nautical mile per hour. A nautical mile is 6,080 feet, or 14% longer than a statute mile (5,280 feet). Thus, if the wind velocity is 20 knots, it is blowing about 23 miles per hour.
True vs. Apparent Wind There is another factor affecting wind strength and direction that we haven't mentioned yet. It has to do with the wind caused by your boat moving through the water. Let's go back for a minute to the meteorologist who held his anemometer out the window of the plane. Even though the boats below had no breeze, he really did feel a strong wind from the south. The reason is that the plane was flying fast in a southerly direction. It's like putting your hand out the window of your car on the interstate. You'll feel a breeze about 60 miles per hour.
The breeze you feel from a moving plane or car is called the "apparent" wind. It works the same for boats, though the effect is less pronounced. Let's pretend you are standing on the end of a dock and the wind you feel is 8 knots from the north. This is called the "true" wind. Now I come sailing by you at five knots, heading east. The wind instruments on my boat say the wind I feel is blowing 10 knots from the northeast. This is my apparent wind; it's a combination of the true wind you feel, plus the wind caused by my boat moving through the water.
When sailing upwind, your apparent wind will be greater than the true wind; if you're sailing downwind, it will be less. The direction of your apparent wind will always be shifted more toward your bow than the true wind. As a sailor, you should be concerned primarily with the apparent wind, because this is the wind in which you sail and it determines how you must trim your sails. That's why it's OK to use telltales and a masthead fly (both of which indicate apparent wind) to determine wind direction.
Whether you're a racer or day sailor, not knowing the wind strength and direction is like driving blindfolded. If you take off the blindfold, suddenly you can predict the sharp turns and give a little more gas before the hills. You'll know where to point your boat and how far in to pull the sails. It's important to keep trying to understand the wind no matter what else you do. This will make learning the sport and controlling your boat much easier.
How the Wind Makes a Sailboat Go
Sailboats are machines that harness the wind for their power. It's easy to understand how the wind can push a boat along with it, but a lot more difficult to figure out how a boat can actually make progress into the wind. It's a little like trying to comprehend how airplanes ever get off the ground.
When I was a young aspiring sailor, I used to build crude model boats consisting of a rectangular piece of wood for a hull, with some sort of stick mast and a square sail made from an old rag. My test area was usually the neighbor's pond, and I quickly learned one thing: the boat only sailed in one direction -- downwind. This meant I could only launch it from the upwind side of the pond.
The ancient sailors faced similar problems. Though they angled their sails to catch the wind and used a paddle to steer, they still had a hard time going anywhere except with the wind . Their eventual solution was a flat board that acted as a kind of brake. They put this board down into the water alongside the boat to keep them from moving sideways.
Today this flat board is called a keel or centerboard, and it's the secret to how a boat can sail into the wind. To imagine how it works, think about squeezing a watermelon seed. When you put pressure on both sides of the seed, it squirts in a direction that's perpendicular to the forces.
With a sailboat, the wind is pushing on the sails on one side while the water pushes on the centerboard, rudder and hull on the other side. As the boat is squeezed by these two forces, it "squirts" forward and is thus able to sail upwind. There are, of course, many more complicated aerodynamic and hydrodynamic reasons why this works, but the important thing to know is that without your keel or centerboard you could not sail toward the wind.