How does sailing upwind work

As soon as you have some speed, start heading closer and closer to the wind. Each time you head up, trim your sails in a little tighter so they stop luffing. When you reach a closehauled course about 45 degrees to the wind , your sails should be trimmed in tightly. Where to look — The skipper should concentrate on the front part of the jib, along the luff of the sail.

If you're on a boat without a jib, such as a Laser, watch the front part of the mainsail. You are looking for two things: 1 A bubble, or backwinding, along the front of the sail; and 2 Movement of the windward and leeward telltales on the sail. Steering by the jib — I learned to sail upwind by using the front part of the jib as a guide. This is a good basic technique.

With the sails trimmed in tight, keep trying to steer a little closer to the wind. When the front part of the jib just starts to backwind or luff , you are sailing as close to the wind as possible. If you head up any farther, more of the wind will hit the back of the jib and a larger part of the sail will luff. This is called "pinching. When you want to make distance to windward, continually try to point the boat as high as possible without pinching and slowing down too much.

Steering by the telltales — Another good way to know how high you can point is by watching the telltales on your jib. These pieces of yarn are usually taped on the sail about a foot back from the headstay. Start out by sailing closehauled with the telltales on each side of the sail streaming straight back.

Then head up slightly. When the jib is about to luff, the windward telltales will start to lift up above a horizontal position. This is a good upwind heading. If the windward telltales get more active than this and start to spin around, you are pinching too much. Telltales will also indicate when you are not sailing as high as possible.

If the leeward telltales start to flutter or drop out of a horizontal position, then you are sailing too low and losing distance to windward. In this case, head up until the leeward telltales straighten out and the windward telltales just begin to move again. Practicing — Finding the upwind groove is a matter of practice as much as anything. You just have to spend time sailing closehauled, watching the luff of the jib and telltales, and constantly trying to head a little higher without losing speed.

If you have a chance to sail upwind next to another boat, you'll get a quick and accurate idea of how efficient a job you're doing. Ultimately, if you can close your eyes and keep your boat going upwind, you'll know you really have the "feel". Steering a boat on a closehauled course is only part of the challenge of getting to an upwind destination.

You can sail closehauled all day, but if you remain on one tack, you are only zigging and not zagging. Making progress upwind requires sailing on both tacks. The act of tacking, by definition, takes you from one tack starboard or port to the other, with your bow swinging through the wind.

The sails begin to luff as you push the tiller over, they flap wildly when you are head to wind, and then they fill again as you reach a closehauled course on the new tack. Before you begin a tack, consider the following requirements:. If there is no water flowing over the rudder, the boat won't turn when you push the tiller over. So don't try to tack when you're going slowly. Instead, turn the boat away from the wind to fill the sails and pick up speed. Tack only when the boat's momentum is sufficient to carry her around through the turn.

If you begin a tack from a reaching course with the sails half way out, it can be difficult to spin the boat all the way through the wind without losing speed. So before you tack, trim your sails in to the center of the boat and head up to a closehauled course. So before you push the tiller over, look around to make sure you have room to tack.

Remember that while you are tacking, you must stay clear of other boats. Once you've got good speed on a closehauled course and have plenty of room on all sides, you are ready to tack. Here is a step-by-step procedure of everything the skipper and crew should do before and during this maneuver.

First of all, the skipper should tell the crew about upcoming tacks. Not all crews are good mind readers. I remember making an unexpected tack in one race at a recent Thistle National Championships. I had to avoid another boat and, unfortunately, didn't have time to warn my crew. When we came out of the tack, my crew was still in the hiking straps — under water on the leeward side.

The moral is if your crew is not ready, a tack can end up in disaster. To make sure everyone is ready, the skipper typically yells "Ready about? What the skipper is saying is: "I'm about to throw the helm over. Are you ready to let go of the old jib sheet, trim in the new and move to the other side? When I am racing, I modify this procedure slightly. I tell my crew that when I say "Ready about," I'll assume they are ready to tack unless I hear an objection.

This usually works, but in a less pressured situation I'd suggest waiting for a positive response. Executing the tack itself is a skill that takes a little practice to perfect. The skipper's first move is to push the tiller to leeward, slowly at first and then faster as the boat reaches head to wind.

While this is happening, the skipper stands up, facing forward, moves across the cockpit and continues turning so he can sit on the new windward rail. He exchanges the mainsheet and tiller behind his back just before or as he sits down, and then brings the tiller back to centerline as the sails fill on the new tack.

Why are eighteen footers always sailing upwind? In a fast boat, there's no point going straight downwind: you can never go faster than the wind. So you travel at an angle. But if your boat is fast enough, then the relative wind always seems to be coming mainly from ahead of you, as these arrows show.

So the eighteen footers never set ordinary spinnakers: they have asymmetrical sails that they can set even when they are travelling at small angles to the apparent wind.

A good list of links to technical material , courtesy of Sailboat Technology. How can you trim the mainsail using blocks and pulleys to multiply your force? More about hull shapes, bouyancy and sails. Australian Marine Services Directory has links to weather services, marine services and other information. Coriolis forces and the reasons behind the major ocean currents and winds. Another puzzle involving relative motion of the air: the plane on the conveyor belt.

Did you know that both the special and general theories of relativity are important in the Global Positioning System? See this link from Univ. See where the satellites are at the moment in this animation from J-Track. Details at Science Outreach Centre news and Activities for students and teachers.

Answer to puzzle. The faster heat is the one with no wind. When the wind and the water both move W to E at 10 kt, the boats drift down the river at 10 kt, with their sails hanging limp. In the heat with no wind as measured on the land , a drifting boat has a headwind of 10 kt. You can tack into that. Of course, you don't get something for nothing. In the heat with wind, the river does very little work on the boat.

In the heat without wind, it exerts much greater force on the boat, in particular on the keel or centreboard. Much of that work goes into disturbing the air downwind of the boat's sails. The man in the photo at right did a lot of sailing on rivers: he would have known that. Modified 10 Jan 03 J. Wolfe unsw. Joe's scientific home page Joe's educational pages Joe's music page.

An experiment. When air moves over a plane's wing, from front to back, wind flowing over the top of the wing has to travel farther than wind flowing under the wing's bottom surface. This creates a pressure difference that lifts the plane.

On a sailboat, wind blowing against the boat at an angle inflates the sail, and it forms a similar foil shape, creating a difference in pressure that pushes the sail perpendicular to the wind direction.

Anderson, this force from the sail's foil shape is combined with and balanced by other forces, including those of the boat's keel the long thin piece that juts down from the bottom of the boat. Together, the forces of drag, from the water, and the pressure from the wind against the sail itself push the craft forward. It moves at an angle opposite the direction of the wind, called windward in sailing terminology.