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Topic: Apparent wind

	News \| TimesDaily.com \| TimesDaily \| Florence, Alabama (AL)
		In sailing, the apparent wind is the actual flow of air acting upon a sail, or the wind as it appears to the sailor.
		The Apparent wind is the wind experienced by an observer in motion and is the relative velocity of the wind in relation to to the observer.
		The apparent wind on-board is often quoted as a speed measured by a masthead transducer containing an anemometer and wind vane that measures wind speed in knots and wind direction in degrees relative to the heading of the boat.
	www.timesdaily.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=apparent_wind (475 words)

	CHAPTER-17-C
		Apparent wind is the wind which is apparent to an observing station which is itself in motion.
		Ballistic wind is a value of wind speed and direction which is considered to be the resultant of the effect of all the true winds acting upon the projectile in flight.
		Apparent wind is the vectorial resultant of the motion of the true wind and the reversed motion of the observing station (article 17C1).
	www.eugeneleeslover.com /USNAVY/CHAPTER-17-C.html (5749 words)

	Science Fair Projects - Apparent wind
		Apparent wind is the breeze felt by an observer.
		For a stationary observer, both apparent wind and true wind are the same.
		Apparent wind is calculated by the sum of two vectors.
	www.all-science-fair-projects.com /science_fair_projects_encyclopedia/Apparent_wind (242 words)

	understand apparent wind
		Apparent wind is a very simple concept that continues to mystify many people who have been sailing for years.
		It is the combination of two winds: the one derived by the boat moving through the air and the wind produced by nature—the true wind.
		As the gust hits, the apparent wind goes aft causing more heeling and less drive and changing the angle of incidence—the angle the apparent wind makes with the sails—so that the sails are now improperly trimmed unless you head up or ease the sheets or traveler.
	www.yachting-life.com /new%20index/frames2/apparant%20wind_frame.htm (1886 words)

	Windsurfing Technique & Apparent Wind
		Apparent Wind is a term that most sailors have heard about but very few really understand.
		Yet, the behaviour of the apparent wind under different conditions has a profound effect on the performance of all sailing craft.
		A sound understanding of the principle of apparent wind will help in improving a sailor's technique on all points of sailing, whether it is in sailing upwind, reaching or broadreaching.
	web.singnet.com.sg /~dgswee (187 words)

	Wind Gradient
		Trimming the sails to the wind, as first approximation, is relatively straightforward: they need to develop an angle of attack of about 15 degrees to the oncoming apparent wind (for the beat or the reach).
		Sailing at an angle of 45 degrees to the true wind, the apparent wind would be at about 30 degrees, and so the jib sheeting angle is about 15 degrees to allow the jib to develop about 15 degrees angle of attack to that apparent wind.
		The closer to the water, the slower the wind; this is the wind gradient, caused by friction between the wind and the water surface and its waves.
	www.onemetre.net /Design/Gradient/Gradient.htm (816 words)

	Catamaran VEGA Sailing School Chapter 6
		Apparent wind is a very simple concept that continues to mystify many people who have been sailing for years.
		It is the combination of two winds: the one derived by the boat moving through the air and the wind produced by nature—the true wind.
		As the gust hits, the apparent wind goes aft causing more heeling and less drive and changing the angle of incidence—the angle the apparent wind makes with the sails—so that the sails are now improperly trimmed unless you head up or ease the sheets or traveler.
	www.catamaranvega.com /vega/sailing/06/lesson6.html (1861 words)

	Headwinds, Crosswinds and Tailwinds by Jobst Brandt
		Unlike wind resistance, climbing effort does not diminish at lower speeds, which is partly why bicycles are used mostly in the flatlands.
		Wind drag is a nonlinear function of the relative wind.
		The wind tunnel data was expressed in units of drag related to the rider's size and units of measure.
	sheldonbrown.com /brandt/wind.html (813 words)

	* Apparent wind - (Boating): Definition
		apparent wind The apparent direction of the wind, which is affected by a boat's motion.
		Apparent wind- The direction of the wind as it appears when the boat is moving.
		Apparent wind is the wind felt in a moving boat.
	en.mimi.hu /boating/apparent_wind.html (430 words)

	Understanding apparent wind (Site not responding. Last check: )
		Apparent wind is the wind shown by a masthead indicator and telltales, the wind you feel on your face while you are sailing.
		But your forward motion results in apparent wind coming from a direction that is slightly forward of the true wind and with a speed that is greater than the true wind.
		Even though the true wind is abeam, you are sailing on a close reach because of the apparent wind.
	www.boatimages.com /articles/understand_appwind/understand_appwind.php (971 words)

	bymnews.com
		As the wind increases, the lightweight, 0.75oz, spinnaker is peeled to the medium weight (1.5 oz) when there is about 12 knots of wind over the deck, then to the heavyweight (2.2 oz) when the wind gets to the high teens.
		Once the apparent wind reaches the mid twenties, the point at which the spinnaker is dropped depends on the sea state and the skill of the helmsman and the trimmers.
		Apparent wind (wind over the deck) is the wind that you actually feel on board, and is the combination of what the wind is actually doing (true wind) and how you are moving through it.
	www.bymnews.com /new/content/view/21310/48 (514 words)

	Feathering Up in the Gusts
		For many situations, the best response by the iikpper to being overtrimmed (because the appaent wind moved aft) is to keep a delicate touch on the tiller, and to let the boat head up so the trim of her sails matches the "new direction" of the apparent wind.
		But the problem is that when you dump wind with the mainsheet, all the airflow on the sail(s) is disrupted and the boat "lurches" back upright suddenly, and slows down.
		They don't perceive that when a gust hits, the apparent wind moves aft, and the boat should be given the freedom to head up.
	www.blumhorst.com /potterpages/feathering-up.htm (525 words)

	Landsailing 101 - Ground School for Land Sailors (Site not responding. Last check: )
		Apparent wind is the wind we seem to feel in a given situation.
		Not only does the apparent wind have a direction which is a combination of the two other winds, but it has a velocity which is a combination as well.
		Imagine that there is a wind blowing from behind you and to your left a little, and you are sailing in a direction that is a little to the left of straight downwind, and you are not sailing very fast..
	www.lathingstodo.com /landsailing/groundschool.htm (3533 words)

	Sailing Downwind
		The apparent wind is the wind you feel as you move.
		The apparent wind can be greater than the true wind, and it is the speed of the apparent wind that matters for the sailor.
		The speed of the apparent wind can be illustrated with a "vector diagram" where the length of the lines indicates speed (in knots or MPH).
	ist-socrates.berkeley.edu /~wprinz/windsurfing/Down.html (890 words)

	[No title] (Site not responding. Last check: )
		For a stationary observer, the apparent wind and the true wind are the same.
		Apparent wind is the sum of two vectors.
		The first vector is the true wind speed.
	www.wikiwhat.com /encyclopedia/a/ap/apparent_wind.html (75 words)

	SailPowerCalc
		All the wind values are apparent wind, not true wind.
		VPPs usually base their data on true wind values, but since boatspeed is unknown, and sails work on apparent wind, SailPowerCalc has to rely on apparent wind.
		Apparent wind angle is measured to the centerline of the boat.
	www.wb-sails.fi /news/SailPowerCalc/SailPowerCalc.htm (1044 words)

	Sailboat steering indicator system - Patent 4022150
		An electrical signal in accordance with the direction of the wind relative to the heading of a sailboat is generated by means of a wind direction sensor and a transducer.
		The output of the summing device which represents the apparent wind direction (relative to boat heading) as modified by a change of rudder signal provides an "apparent wind track" error signal which is used to drive a servo motor.
		In the operation of a sailboat it is desirable to steer to and hold headings at a predetermined constant angle with respect to the apparent wind direction in the presence of changing sea and wind conditions.
	www.freepatentsonline.com /4022150.html (3107 words)

	Kiteboarding kite repairs / replacement bladders
		The biggest factor is apparent wind, one must understand what apparent wind is and how to make it work.
		Apparent wind is the vector addition of the true wind speed, and the speed the rider is traveling.
		Consider the example where we have 10 knots of N wind, and you are riding E at 10 knots.
	www.airpadrekiteboarding.com /light-wind-kiteboarding.php (994 words)

	Wind and course calculator for navigation - Patent 4652728
		The data supplied by the boat's instruments are the speed of the apparent wind, its direction with respect to the axis of the boat (trim), the drift, the speed and the direction of the boat, whereas the characteristics of the current are available from the map depending on the times of tides.
		The second operation consists in indicating using dot 13 on the mobile disk the direction of the wind, of the course or heading and, by sliding slider 12 along the pointer, in placing dot 13 on the value of the speed of the wind or that of the boat.
		For calculating the true wind (TW) without current or the surface wind (SW) with current, the first operation consists in indicating the sailing trim to which the drift has been added by means of arrow 10 on the scale of the supporting disk.
	www.freepatentsonline.com /4652728.html (3212 words)

	Windvane, Autopilot, steering systems
		With the wind aft of the beam, the autopilot tries to steer a compass course, and the changes in the apparent wind result in the sails performing at less than maximum efficiency.
		With the wind forward of the beam and the autopilot steering to a set apparent-wind angle, there wasn't much to choose between the autopilot and the windvane, though it was clear that the windvane yielded more miles made good at the smaller apparent-wind angles.
		If the wind was between 85 and 95 degrees apparent, it was better to set the autopilot on a fixed compass course, and with this, the autopilot yielded more miles made good than the windvane.
	members.shaw.ca /taonui/windvane.html (1735 words)

	sailpower.com
		The wind perceived on a boat is affected by three separate factors.
		The second is the wind generated by the passage of the boat through the air, which is in an opposite direction to the boat's course and at the same speed.
		However, when the motion of the boat over the sea is modified by a tidal current, the apparent wind perceived aboard will be the resultant of waterflow, boat motion through the water and true wind.
	www.sailpower.com /sp/features/tidal/index.html (721 words)

	NAUTICALweb - Aerodynamic simulation of upwind and downwind sails
		The interaction between the flowing wind and the two sails generates an overall force acting on the sails which can be split into a drag force, in the direction of the incoming apparent wind, and into a lift force, perpendicular to it.
		However, because in the general case the wind blows in a direction which is not the direction of the sailboat motion, it is more convenient to split the overall force into a thrust force in the direction of the boat motion and into a side force, perpendicular to the direction of motion.
		Experimental measurements, obtained for a scaled model (1:12.5) at the wind tunnel of the University of Auckland in New Zealand, are available in the literature and are reported in the two figures together with the results of the viscous and inviscid computations.
	www.nautica.it /superyacht/517/tecnica/sail.htm (2578 words)

	How does it sail
		When the true winds strength will go back to its previous state, the apparent wind will change again (will blow more from the front, because once again the wind of the boats' own speed remains the same).
		Once you remember that the telltales show only the apparent wind, and that this winds direction may change with the strength of the true wind changing, you'll then be able to steer your boat in the most advantageous way.
		When the wind blows astern, the boat is driven forward by the force of resistance to the wind.
	www.angelfire.com /bug2/bugged/how_does_it_sail.htm (700 words)

	FAQ - Kitesurf Wiki - a Wikia wiki
		When kitesurfing in a straight line, the kite's apparent wind is a combination of the wind speed and the speed of the kite and rider over the surface, but since the kite is highly steerable apparent wind can vary widely depending on how the kite is being flown.
		In normal riding, the kiteboarder takes a heading which is as close to into the wind as possible, and in any event leads at some angle slightly upwind, sometimes as much as 45 degrees; jumping or wave riding usually results in traveling downwind, so the net result is to maintain relative position.
		If the rider is facing downwind on a flat surface, like the ocean, the wind window consists of roughly all the area the rider can see, from the rider's peripheral vision on one side, along the horizon to the other side, and then directly overhead back to the first side.
	kitesurf.wikia.com /wiki/FAQ (1392 words)

	June 25, 2003: Wind Power Set to Become World's Leading Energy Source
		Wind Force 12 projected that the average cost per kilowatt hour of wind-generated electricity will drop to 2.6¢ by 2010 and to 2.1¢ by 2020.
		For Germany, this rapid growth in wind power is central to reaching its goal of reducing carbon emissions 40 percent by 2020.
		With the wind industry's engineering know-how and manufacturing experience, it would be relatively easy to scale up the size of the industry, even doubling it annually for several years, if the need arose.
	www.earth-policy.org /Updates/Update24.htm (1269 words)

	Sail Trim
		The apparent wind is forward of the true-wind, except when sailing directly into or away from the true-wind.
		In general, the closer you sail to the wind, the closer the sails are pulled or trimmed to the midline of the boat.
		The speed of the boat is mainly dependent upon the amount of sail hoisted and, in a hull displacement boat, the length of the hull at the waterline.
	www.sailingusa.info /sail_trim.htm (1297 words)

	Miller's 1933 Cosmic Model
		In this paper, the cosmic ether wind is assumed to operate outside an entrained ether bubble that rotates with the Earth as a “solid” body, and the near ether wind is assumed to operate inside that bubble.
		At the ground terminal of this helical trajectory, the helical ether wind speed in the direction of the helical path is presumed to be the exhaust velocity of 57.2 km/s.
		is the apparent ether wind from the CMB that is aberrated by the Sun’s motion.
	home1.gte.net /res00bfl/millers_cosmic_model.htm (6802 words)

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