It seems obvious how a sailboat sails downwind: It is pushed along by the wind in its sails. Less obvious is how it can sail upwind or how some sailboats can sail faster than the wind.
Sir Isaac Newton formulated three basic laws that pertain to the motions and accelerations of all objects.
Let us have a look at the third law:
For any force exerted on an object, an equal but opposite force must be exerted by that object onto whatever exerted the force.
A direct consequence of this law is the conservation of momentum (Momentum equals mass times velocity). The conservation of momentum tells us that if the velocity of one thing is somehow changed (in either magnitude or direction) that the velocity of something else must also change accordingly.
Moreover, a large change in velocity of a light object can be balanced by a small change in velocity of a massive object. This is, of course, how a sailboat sails. Because of its large sail area, a sailboat can change the velocity of a huge amount of air in a small amount of direction or speed.
The change of velocity that the sailboat imparts to the air hitting her sails is mainly a change in the direction in which the air is moving. So a sailboat can experience a large driving force even when she is sailing against the wind.
In the real world, there are two forces. One is the wind pushing on the sail when it is changing direction. The air traveling over the leeward surface of the cambered sail creates the second force. It has to travel a longer way to reach the end of the sail (the leech), and as a consequence goes faster. This is causing a pressure differential in accordance with Bernoulli’s principle. (More speed gives less pressure and less speed gives more pressure).
So a sailboat can sail upwind with the addition of these two forces. But remember that the force created by the depression is four times bigger that the one created by pushing the air sideways.
A fluid flow exerts a force upon an object in a direction perpendicular to the uninterrupted flow of that fluid. As a result, a lift is generated. But there is also creation of a drag that is a force acting in the direction of the fluid.Because lift and drag are defined as being perpendicular to one another, any force acting on a sail can, using trigonometry, be divided into a lift component and a drag component. By separating the force into these two components, we can study the relationships between lift, drag, the shape of the sail, and the angle between the sail and the airflow( AOA or Angle Of Attack with the Greek letter).
Sailing is not a complicated sport. Anyone can do it and enjoy it.
Spend time on the water
You just need to take a little time on the water. Trying and collecting experience is one of the best way to learn. I am sure you will have a great time on the water.
You can start just by yourself.
Plenty of sailors started buying, renting, borrowing or otherwise obtaining a boat for their first sail without any knowledge.
Let me say that you have to take care because it could be hazardous to your health.
Get the Right Boat
For a child, learning to sail in a dinghy seems natural. For an adult, it is not so simple. You react less by instinct and fear to go on this unstable machine could surface. For this reason, many people opt for a larger, seemingly more forgiving big boat to learn on.
It is another way, but they miss out on a pure form of sailing not experienced in larger boats. Is it Dangerous?
Which danger could threaten you on a small sailing boat? You could tip over. It is called “Capsize”. Capsizing and learning to right your boat again are all part of the learning process and could be fun.
With the fear of capsize behind you, you will be able to concentrate wholly on sailing maneuvers instead of constantly worrying about getting wet.
Don't wait and Jump
Remember, you told everyone that you would like to become a sailor and go across oceans…
Well, it's time to make good on that.
At first, gauge how you feel about the water.
During your last summer vacation, did you jump right in the water or did you cautiously wade in? Okay, I agree it could depend of the weather and the temperature of the water.
But if you're a jumper, you can stop reading here. Just take a day off from the office, buy or rent a boat, or ask an old friend sailor to come with you, and get out of here!
If you're still with me, then you're a wader. Don’t worry. I am not a jumper too, and I sailed during the last 40 years having fun. It is difficult for me to take the decision to go, but if I fall, by accident,in the (cold) water, it is not such a big problem for me. The more I think about, the less I go…
Have no fear. Nobody is going to splash you. Let's start with dipping our toes into the water. The way to do that with sailing is to go out and buy a few books about the sport. Stay away from anything boring, technical, or overly historical. You need an easy book, with a lot of drawings, and nice to read.
Lobbying, Lobbying
Now let's go to a more serious work. Figure out a way to catch an invitation onto a sailboat. The important thing is to get sailing. You can pay to go on a sailing boat with skipper, or twist a friend’s arm to be invited aboard his next sail. I don’t care the method. You need to go on the water. As a good info, it is very rare to be sick on small boats. You are outside, in the wind, all thing concurring to have you feeling well.
Just take care not to do a race with a crazy guy who will cure you of sailing. You have to start with a mellow sailing day.
Take a Course
It's time to move on to the second step. Find an adult sailing course and sign up for it. Personally, I would recommend taking your first lessons in a small sailing boat, a dinghy. For sailing courses they are designed for beginners. They will give you an immediate response to any shifts in the variables that affect sailing (weight, wind, waves, and weather).
If your wife (or your husband, boyfriend or girlfriend) wants to learn sailing too, take separate classes. It's difficult enough to learn a new sport without having your partner watching over your shoulder at every step of the way.
It will be time later to sail (and should the occasion arise, to fight) all together, as an old couple, on the same boat.
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