Past Lessons...
Now, that you know the basics of steering and sail trim, the next step in becoming a skilled sailor is learning more about how the wind powers your sails.
In ancient times the only way a boat could sail was with the wind pushing from behind, called running. This made it hard for the sailors to get where they wanted to go. They were at the mercy of the wind. If the wind was not blowing in the direction that they wanted to go, they would be forced to sail many miles out of their way in order to reach their desired destination.
You can easily see how a boat is pushed forward when the wind is behind it, but how does the wind make youy boat go forward when the wind blows from the side or even from the bow?
Next time you
are out sailing, look closely at the mainsail. When the wind is blowing,
the sail is no longer a flat triangle but rather a curved shape and with
a deep pocket along the luff edge. The curve is similar to an airplane
wing and works in the same manner. Try and imagine you are looking at a
cross sectional edge of an airplane wing. You will notice more curvature
on the top than on the bottom. As the air stream approaches the front of
the wing, it splits, with some air going over the wing and some going under.
because the wing is curved on top, the air that follows this route has
a longer way to go. Therefore it must travel faster to meet the air on
the bottom.
According to Bernoulli, the guy who came up with the principle, the faster air verlocity on top means there is less pressure there and more pressure underneath. Therefore, the wing tends to lift in the direction of the lower pressure. This lifting effect is called an airfoil.
A sail works in much the same way. As wind approaches the leading edge
of the sail, it separates and flows along both sides of the sail from luff
to leech. The air on the windward side reaches the leech first, since it
has a shorter route to travel. The results is lower pressure on the leeward
side of the sail creating a lift perpendicular to the wind. 
Another way to look at how an airfoil works is the wind on the outside curve is spread out, so its pressure is lower. The wind on the inside piles up, and its pressure is higher. The result is that the high pressure inside pushes on the sail, while the low pressure outside creates suction. Together they make a push-pull effect that drives the boat forward.
The push-pull action drives the boat forward and sideways. The centerboard or keel prevents the boat from slipping sideways.
You can prove to yourself that this really works by taking a piece of notebook paper and holding it up horizontally by the two corners in front of your face. The far edge of the paper will drop down because of gravity. Now blow hard along the top surface. The paper will be sucked back up to the horizontal. Your sail works in the same way.
Every boat undersail is on either a starboard tack or port tack. There are two ways to change directions. If going upwind the term used is coming about, this is accomplished by putting your bow through the no-sail zone. If going downwind the term used is jibbing, this is achieved by passing the stern through the no-sail zone.
Coming about is the method used to change the wind's direction over the bow of a sailboat going to wind ward. Before giving a detailed description of coming about let's look at the step by step commands given by the helmsman.
1. Ready About is given by the helmsman to alert the crew.
2. Helms Alee is given at the moment he pushes the tiller toward
the boom.
3. As the bow approaches head to wind (no-sail zone) the jib begins to
fill on the wrong side backing the bow to the new tack as the helmsman
pulls the tiller amidships.
4. When the mainsail fills he gives the order to release the jibsheet
and recleat the jib sheet for the new tack.
When you
push the tiller toward the boom, the bow will move into the wind and you
will quickly lose speed. Watch your sails during this move, they will shift
toward the center of the boat. When you get all the way into the no-sail
zone, your sails will flap. Don't linger there at all. Go all the way through
the wind. Keep your tiller pushed toward the mainsail when you are in the
no-sail zone, and you will turn all the way through it and come out into
the sail zone on the other side.
Your boom and sails will move across the centerline of the boat. As your boat changes direction, the sails fill and pick up the wind on the new leeward side and pull you right out of the no-sail zone.
Once on the other side of the no-sail zone, straighten the tiller, bring the helm amidships-to stop the turn and hold your new course.
The momentum or speed you gained in sailing a straight course will give you the power to cross through the no-sail zone and pick up the wind on the other side.
As the jib luffs, let go of the jibsheet on the leeward side. The jib will flap through the no-sail zone and move to the other side of the boat. As you steady the tiller on your new course, trim, or pull in , the jibsheet so that the jib is just inside of the luff point.
The boom and mainsail will also move across the boat. Duck out of the way of the boom, so it doesn't hit your head.
Having changed tacks, you must move your body to the new windward side. Remember as skipper you should always face forward to see where your boat is headed. As you change sides, pass the tiller from hand to hand behind your back. Changing body position and steering a straight course will become easy with some practice.
After changing your body position on the new side your boat will take a moment to regain the momentum you had on the previous tack. Be patient and do not over steer.
If you intend to have crew with you, don't forget to prepare them by saying: "Ready about" and "Helms alee." This will make them pay attention. Have the crew respond by saying "Ready," as soon as they are ready. Even if you are by yourself you can still say "Prepare to come about" to put yourself into the ready mode.
Preparing the boat
for a jibe is slightly different from coming about (Tacking). A jibe is
done simply by turning the stern through the wind, as opposed to tacking
when the bow passes through the wind. The helmsman bears away until the
wind strikes the opposite side of the boom and the sail swings over to
the opposite side, and the helmsman immediately has to counteract the boats
tendency to luff up sharply. At the same time the jib sheet is eased rapidly.
When jibing, your bow will be turning away from the wind. That means that you will be changing from a beam or broad reach, or even running, on one tack to the same thing on the other tack.
The jibe can be one of the most dangerous maneuvers on a sailboat. I am not certain but I think some ancient sailor named the boom, the boom, because he didn't duck. Be very careful.
As you move your stern across the wind, the change of tack downwind will bring the boom swinging across the cockpit. This is when you must pay attention and duck as it crosses.
To stop any violent swinging of the boom, you must center the boom by pulling all the way in on the mainsheet. A good time to center the boom is when you shout Prepare to Jibe! Your crew responds Ready! You then shout Jibbing, this will let your crew know that you are turning to the new tack. At this moment cast off the jibsheet on the old leeward side and pull in on the new leeward side as the boat turns and picks up the wind again.
As the mainsail jibes over, ease the boom out, to it's desired reach or run position. Also, move your body to the new windward side, still facing forward and changing the tiller and mainsheet to the other hand from behind your back.
Heel Leaning
of the boat to one side in response to the wind. A boat may be heeled deliberately
by the crew, for example to help the sails to fill and reduce wetted hull
area in a light breeze.
A boat that heels easily is said to be tender (ultra light racers, small dagger and center board boats, dinghies), one that heels less easily is stiff (full keel boats, heavy cruisers).
Heeling on a breezy day is fun. Your sailboat is designed and built to lean quite a bit without swamping or tipping over, so enjoy the feeling. It's fun to go out with a friend and hike out. Hiking is when you balance your boat with your body. This can be done several ways. Some boats have hiking straps that run along side of the center board trunk. By slipping your feet under the hiking strap you will be able to lean further out for maximizing your balancing power and will prevent you from falling out. If you don't have hiking straps, installation is simple.
Sit way out over the windward side. Hold on to the mainsheet or jibsheet and lean back to try to hold the boat flat. Expect to get a little wet, on warm days it's refreshing.
Most sailors in the beginning, while their learning, are uncomfortable to let their boat heel because of the fear of capsizing or loosing control.
If the wind changes and you feel you are heeling too far, ease the main out to spill some wind. Unsuccessful heeling means capsizing. The main is your best friend while heeling. When in doubt let it out. You should never be frightened of capsizing. Next month we will learn how to right your boat after a capsize.
For maximum speed and efficiency most boats are designed for self-steering hull balance thru a heel range of 5 to 15 degrees. If heeling further then 15 degrees you will experience weather helm. This means you will have to compensate with the rudder to steer a straight course resulting in excessive rudder drag causing the boat to slow down. You will feel more pressure from the tiller.
A well balanced boat is correctly trimmed (crew weight in the right position) and the sails sheeted to the correct angle for the point of sailing. an unbalanced boat has weather helm, unnecessary pressure on the rudder and tiller.
Capsizing is when your boat turns keel uppermost, but a capsized dinghy may be either floating with the mast and sail lying on the water, or may have turned turtle lying with the mast pointing downwards. A keel boat with a water tight or self draining cockpit normally rights herself because of the weight of the ballast keel.
A dinghy on the other hand has to be righted by the crew and the method varies according to the boat, weather and the number of the crew.
The centerboard case must be high enough to be clear above the water even when the boat is awash and must have adequate buoyancy.
Capsizing isn't scary or dangerous on a fair-weather day if you know how to swim. Before ever stepping into a sailboat you must learn how to swim. So the first lesson in sail boating should be, learn how to swim.
Capsizing usually results from heeling to far or an accidental jibe. If you feel your in real danger in tipping over, luff the main sail at once, by letting the main sheet fly. If your boat does go over on its side, stay with it, never swim away. You must do several things quickly.
First, make sure that no one is trapped under the boat or tangled in the rigging. if they are, help them to get free. next, stand on the centerboard as quickly as possible to prevent the boat from turning completely upside down. Be sure the mainsheet is free and free the jibsheets so the sails will not fill with water when the boat is capsized or with air when it is right side up again. If possible try to swim the bow around into the nosail zone.
Then swim back to the side of the boat, grab the gunwale or the shrouds, stand on the centerboard, and lean back with all your weight. This leverage should slowly bring the boat back up. hang On. Pull and slither yourself aboard over the side or the stern.
Things will be a jumbled mess. start to bail, unless you have a self bailing cockpit and can sail it dry. Get one sail sheeted in and pulling enough to get some movement and then steer a comfortable course like a beam reach, to give the crew a few minutes to sort things out.
If the boat turns upside down, you should still use the centerboard as a lever, but it will need much more effort.
Even if the centerboard slips back down into the hull, it is possible to bring one jibsheet up over the hull, stand on the opposite gunwale, and gradually haul the mast back to the surface and then upright, though this is a real feat of strength.
Above all, remember to stay with your boat. As long as its floating you will be safe. Remember the boat does not get tired and it can be visible a long way off. Don't ever think of swimming ashore.
On a calm day, in a protected area and with supervision, capsize your boat and right it several times to get confidence. You will be surprised how easy it will become with a little experience.
