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Polar Diagram (sailing)
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. 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 drawn on the chart representing wind speed. To identify how fast a yacht could potentially go you select a particular wind speed curve and particular wind angle. Refer to the graph to the right for an example. Polar diagrams are normally specific to a particular sailboat design and are created by the yacht designer. Polar diagrams can also be created using a velocity prediction program or by a range of computer programs including iPolar and iRegatta. See also * Forces on sails External links ORC Sailboat Dataa large database of polar diagrams maintained by the Offshore Racing Congress The Offshore Racing Congress (ORC) is an international body ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Downwind Polar Diagram To Determine Velocity Made Good At Various Wind Speeds
Windward () and leeward () are terms used to describe the direction of the wind. Windward is ''upwind'' from the point of reference, i.e. towards the direction from which the wind is coming; leeward is ''downwind'' from the point of reference, i.e. along the direction towards which the wind is going. The side of a ship that is towards the leeward is its "lee side". If the vessel is heeling under the pressure of crosswind, the lee side will be the "lower side". During the Age of Sail, the term ''weather'' was used as a synonym for ''windward'' in some contexts, as in the ''weather gage''. Because it captures rain, the windward side of a mountain tends to be wet compared to the leeward it blocks. Origin The term "lee" comes from the middle-low German word // meaning "where the sea is not exposed to the wind" or "mild". The terms Luv and Lee (engl. Windward and Leeward) have been in use since the 17th century. Usage Windward and leeward directions (and the points of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chart
A chart (sometimes known as a graph) is a graphical representation for data visualization, in which "the data is represented by symbols, such as bars in a bar chart, lines in a line chart, or slices in a pie chart". A chart can represent tabular numeric data, functions or some kinds of quality structure and provides different info. The term "chart" as a graphical representation of data has multiple meanings: * A data chart is a type of diagram or graph, that organizes and represents a set of numerical or qualitative data. * Maps that are adorned with extra information (map surround) for a specific purpose are often known as charts, such as a nautical chart or aeronautical chart, typically spread over several map sheets. * Other domain-specific constructs are sometimes called charts, such as the chord chart in music notation or a record chart for album popularity. Charts are often used to ease understanding of large quantities of data and the relationships between parts of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sailboat
A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture. Types Although sailboat terminology has varied across history, many terms have specific meanings in the context of modern yachting. A great number of sailboat-types may be distinguished by size, hull configuration, keel type, purpose, number and configuration of masts, and sail plan. Popular monohull designs include: Cutter The cutter is similar to a sloop with a single mast and mainsail, but generally carries the mast further aft to allow for a jib and staysail to be attached to the head stay and inner forestay, respectively. Once a common racing configuration, today it gives versatility to cruising boats, especially in allowing a small staysail to be flown from the inner stay in high winds. Catboat A catboat has a single mast mounted far forward and does not carr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line Chart
A line chart or line graph or curve chart is a type of chart which displays information as a series of data points called 'markers' connected by straight line segments. It is a basic type of chart common in many fields. It is similar to a scatter plot except that the measurement points are ordered (typically by their x-axis value) and joined with straight line segments. A line chart is often used to visualize a trend in data over intervals of time – a time series – thus the line is often drawn chronologically. In these cases they are known as run charts. History Some of the earliest known line charts are generally credited to Francis Hauksbee, Nicolaus Samuel Cruquius, Johann Heinrich Lambert and William Playfair. Example In the experimental sciences, data collected from experiments are often visualized by a graph. For example, if one collects data on the speed of an object at certain points in time, one can visualize the data in a data table such as the following: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Velocity Prediction Program
A velocity prediction program (VPP) is a computer program which solves for the performance of a sailing yacht in various wind conditions by balancing hull and sail forces. VPPs are used by yacht designers, boat builders, model testers, sailors, sailmakers, also America's Cup teams, to predict the performance of a sailboat before it has been built or prior to major modifications. Background The first VPP was developed at the Massachusetts Institute of Technology during the early 1970s when Commodore H. Irving Pratt funded research to predict the performance ''"of a sailing yacht, given knowledge of its hull, rig and sailplan geometry"''. Methodology VPPs are iterative programs which require educated guesses of initial parameters to begin operating. Generally VPPs are composed of two mechanisms, a ''boat model'' and a ''solution algorithm''. Initial guesses of parameters including boat speed (Vs), heel angle (Φ), number of reefs and sail flatness are input into the ''bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forces On Sails
Forces on sails result from movement of air that interacts with sails and gives them motive power for sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and sail-powered land vehicles. Similar principles in a rotating frame of reference apply to windmill sails and wind turbine blades, which are also wind-driven. They are differentiated from forces on wings, and propeller blades, the actions of which are not adjusted to the wind. Kites also power certain sailing craft, but do not employ a mast to support the airfoil and are beyond the scope of this article. Forces on sails depend on wind speed and direction and the speed and direction of the craft. The direction that the craft is traveling with respect to the "true wind" (the wind direction and speed over the surface) is called the point of sail. The speed of the craft at a given point of sail contributes to the "apparent wind"—the wind speed and direction as measured on the moving craft. The apparen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Offshore Racing Congress
The Offshore Racing Congress (ORC) is an international body for the sport of competitive sailing and is responsible for the establishment and maintenance of rating and classification standards used to define offshore, that is marine as opposed to inland, yacht racing handicap categories. Ratings and Classification The ORC was established in 1969 to create a single international handicap standard to combine the two pre-existing dominant handicap standards - that of the Cruising Club of America which covered North and South Americas, and the standard of the Royal Ocean Racing Club for Europe and the Antipodes. The combined ruleset, the International Offshore Rule or IOR, was initially successful. The ORC developed International Measurement System (IMS) in the early 1990s and it was widely used to the early 2000s. This made use of a Velocity prediction program or VPP. While still maintained, the IMS has been largely superseded by the Offshore Racing Congress Rule in its Internatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naval Architecture
Naval architecture, or naval engineering, is an engineering discipline incorporating elements of mechanical, electrical, electronic, software and safety engineering as applied to the engineering design process, shipbuilding, maintenance, and operation of marine vessels and structures. Naval architecture involves basic and applied research, design, development, design evaluation (classification) and calculations during all stages of the life of a marine vehicle. Preliminary design of the vessel, its detailed design, construction, trials, operation and maintenance, launching and dry-docking are the main activities involved. Ship design calculations are also required for ships being modified (by means of conversion, rebuilding, modernization, or repair). Naval architecture also involves formulation of safety regulations and damage-control rules and the approval and certification of ship designs to meet statutory and non-statutory requirements. Main subjects The word "vessel" in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_and_down_wind_(left).jpg "Click for more on -> Forces On Sails")
