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The combination of a sailing craft's speed and direction with respect to the wind, together with wind strength, generate an apparent wind velocity. When the craft is aligned in a direction where the sail can be adjusted to align with its leading edge parallel to the apparent wind, the sail acts as an airfoil to generate lift in a direction ...
The apparent wind on board (a boat) 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. Modern instrumentation can calculate the true wind velocity when the apparent wind and boat speed and ...
A ship in a force 12 ("hurricane-force") storm at sea, the highest rated on the Beaufort scale. The Beaufort scale (/ ˈ b oʊ f ər t / BOH-fərt) is an empirical measure that relates wind speed to observed conditions at sea or on land. Its full name is the Beaufort wind force scale.
Hull speed can be calculated by the following formula: where is the length of the waterline in feet, and is the hull speed of the vessel in knots. If the length of waterline is given in metres and desired hull speed in knots, the coefficient is 2.43 kn·m −½.
If a craft proceeds at 90° to a true wind of V T = 10 knots, itself traveling at a speed inducing V B = 10 knots, then the apparent wind angle would be 45° off the bow and the apparent wind speed would be about 14 knots, calculated as: square root [(V B) 2 + (V T) 2] = square root [10 2 + 10 2] = 14.14. As the craft becomes faster than the ...
Such as, a vessel has a speed of 8 knots through the water and the vessel is traveling with the current, which is at 2 knots, then the speed over ground is 8+2 and the vessel's true speed is 10 knots. Set and Drift can be calculated by using a vector diagram and can be drawn and measured on a chart, maneuvering board or even a plain piece of paper.
A polar diagram, or polar plot, is a graph that shows a sailboat's potential speed over a range of wind speeds and relative wind angles. [1] It normally consists of the right side of a line chart with the radius representing the yacht speed and the angle representing the wind direction blowing from top to bottom. Several lines are normally ...
The reference wind pressure q is calculated using the equation q = ρv 2 / 2, where ρ is the air density and v is the wind speed. [ 19 ] Historically, wind speeds have been reported with a variety of averaging times (such as fastest mile, 3-second gust, 1-minute, and mean hourly) which designers may have to take into account.