In the 21st century, most sailing represents a form of recreation or sport. Recreational sailing or yachting can be divided into racing and cruising. Cruising can include extended offshore and ocean-crossing trips, coastal sailing within sight of land, and daysailing.
Sailing relies on the physics of sails as they derive power from the wind, generating both lift and drag. On a given course, the sails are set to an angle that optimizes the development of wind power, as determined by the apparent wind, which is the wind as sensed from a moving vessel. The forces transmitted via the sails are resisted by forces from the hull, keel, and rudder of a sailing craft, by forces from skate runners of an iceboat, or by forces from wheels of a land sailing craft which are steering the course. This combination of forces means that it is possible to sail an upwind course as well as downwind. The course with respect to the true wind direction (as would be indicated by a stationary flag) is called a point of sail. Conventional sailing craft cannot derive wind power on a course with a point of sail that is too close into the wind.
Sailing By Download
DOWNLOAD 🔥 https://urloso.com/2yGc4I 🔥
Throughout history, sailing was a key form of propulsion that allowed for greater mobility than travel over land. This greater mobility increased capacity for exploration, trade, transport, warfare, and fishing, especially when compared to overland options.[citation needed]
During the Age of Discovery, sailing ships figured in European voyages around Africa to China and Japan; and across the Atlantic Ocean to North and South America. Later, sailing ships ventured into the Arctic to explore northern sea routes and assess natural resources. In the 18th and 19th centuries sailing vessels made Hydrographic surveys to develop charts for navigation and, at times, carried scientists aboard as with the voyages of James Cook and the Second voyage of HMS Beagle with naturalist Charles Darwin.
Iron-hulled sailing ships represented the final evolution of sailing ships at the end of the Age of Sail. They were built to carry bulk cargo for long distances in the nineteenth and early twentieth centuries.[20] They were the largest of merchant sailing ships, with three to five masts and square sails, as well as other sail plans. They carried bulk cargoes between continents. Iron-hulled sailing ships were mainly built from the 1870s to 1900, when steamships began to outpace them economically because of their ability to keep a schedule regardless of the wind. Steel hulls also replaced iron hulls at around the same time. Even into the twentieth century, sailing ships could hold their own on transoceanic voyages such as Australia to Europe, since they did not require bunkerage for coal nor fresh water for steam, and they were faster than the early steamers, which usually could barely make 8 knots (15 km/h).[21] Ultimately, the steamships' independence from the wind and their ability to take shorter routes, passing through the Suez and Panama Canals, made sailing ships uneconomical.[22]
Until the general adoption of carvel-built ships that relied on an internal skeleton structure to bear the weight of the ship and for gun ports to be cut in the side, sailing ships were just vehicles for delivering fighters to the enemy for engagement.[23] Early Phoenician, Greek, Roman galleys would ram each other, then pour onto the decks of the opposing force and continue the fight by hand, meaning that these galleys required speed and maneuverability.[24] This need for speed translated into longer ships with multiple rows of oars along the sides, known as biremes and triremes.[25] Typically, the sailing ships during this time period were the merchant ships.[26]
By 1500, Gun ports allowed sailing vessels to sail alongside an enemy vessel and fire a broadside of multiple cannon.[27] This development allowed for naval fleets to array themselves into a line of battle, whereby, warships would maintain their place in the line to engage the enemy in a parallel or perpendicular line.[28]
While the use of sailing vessels for commerce or naval power has been supplanted with engine-driven vessels, there continue to be commercial operations that take passengers on sailing cruises.[29][30] Modern navies also employ sailing vessels to train cadets in seamanship.[31] Recreation or sport accounts for the bulk of sailing in modern boats.
Day-sailing primarily affords experiencing the pleasure of sailing a boat. No destination is required. It is an opportunity to share the experience with others.[32] A variety of boats with no overnight accommodations, ranging in size from 10 feet (3.0 m) to over 30 feet (9.1 m), may be regarded as day sailors.[33]
Cruising on a sailing yacht may be either near-shore or passage-making out of sight of land and entails the use of sailboats that support sustained overnight use.[34] Coastal cruising grounds include areas of the Mediterranean and Black Seas, Northern Europe, Western Europe and islands of the North Atlantic, West Africa and the islands of the South Atlantic, the Caribbean, and regions of North and Central America.[35] Passage-making under sail occurs on routes through oceans all over the world. Circular routes exist between the Americas and Europe, and between South Africa and South America. There are many routes from the Americas, Australia, New Zealand, and Asia to island destinations in the South Pacific. Some cruisers circumnavigate the globe.[36]
Sailing as a sport is organized on a hierarchical basis, starting at the yacht club level and reaching up into national and international federations; it may entail racing yachts, sailing dinghies, or other small, open sailing craft, including iceboats and land yachts. Sailboat racing is governed by World Sailing with most racing formats using the Racing Rules of Sailing.[37] It entails a variety of different disciplines, including:
A saildrone is a type of unmanned surface vehicle used primarily in oceans for data collection.[44] Saildrones are wind and solar powered and carry a suite of science sensors and navigational instruments. They can follow a set of remotely prescribed waypoints.[45] The saildrone was invented by Richard Jenkins, a British engineer,[46] founder and CEO of Saildrone, Inc. Saildrones have been used by scientists and research organizations like the National Oceanic and Atmospheric Administration (NOAA) to survey the marine ecosystem, fisheries, and weather.[47][48] In January 2019, a small fleet of saildrones was launched to attempt the first autonomous circumnavigation of Antarctica.[49] One of the saildrones completed the mission, traveling 12,500 miles (20,100 km) over the seven month journey while collecting a detailed data set using on board environmental monitoring instrumentation.[50]
In August 2019, SD 1021 completed the fastest unmanned Atlantic crossing sailing from Bermuda to the UK,[51] and in October, it completed the return trip to become the first autonomous vehicle to cross the Atlantic in both directions.[52] The University of Washington and the Saildrone company began a joint venture in 2019 called The Saildrone Pacific Sentinel Experiment, which positioned six saildrones along the west coast of the United States to gather atmospheric and ocean data.[53][54]
In points of sail that range from close-hauled to a broad reach, sails act substantially like a wing, with lift predominantly propelling the craft. In points of sail from a broad reach to down wind, sails act substantially like a parachute, with drag predominantly propelling the craft. For craft with little forward resistance, such as ice boats and land yachts, this transition occurs further off the wind than for sailboats and sailing ships.[58]
True wind velocity (VT) combines with the sailing craft's velocity (VB) to give the apparent wind velocity (VA), the air velocity experienced by instrumentation or crew on a moving sailing craft. Apparent wind velocity provides the motive power for the sails on any given point of sail. It varies from being the true wind velocity of a stopped craft in irons in the no-go zone, to being faster than the true wind speed as the sailing craft's velocity adds to the true windspeed on a reach. It diminishes towards zero for a craft sailing dead downwind.[59]
The speed of sailboats through the water is limited by the resistance that results from hull drag in the water. Ice boats typically have the least resistance to forward motion of any sailing craft.[58] Consequently, a sailboat experiences a wider range of apparent wind angles than does an ice boat, whose speed is typically great enough to have the apparent wind coming from a few degrees to one side of its course, necessitating sailing with the sail sheeted in for most points of sail. On conventional sailboats, the sails are set to create lift for those points of sail where it's possible to align the leading edge of the sail with the apparent wind.[59]
For a sailboat, point of sail affects lateral force significantly. The higher the boat points to the wind under sail, the stronger the lateral force, which requires resistance from a keel or other underwater foils, including daggerboard, centerboard, skeg and rudder. Lateral force also induces heeling in a sailboat, which requires resistance by weight of ballast from the crew or the boat itself and by the shape of the boat, especially with a catamaran. As the boat points off the wind, lateral force and the forces required to resist it become less important.[60]On ice boats, lateral forces are countered by the lateral resistance of the blades on ice and their distance apart, which generally prevents heeling.[61]
Wind and currents are important factors to plan on for both offshore and inshore sailing. Predicting the availability, strength and direction of the wind is key to using its power along the desired course. Ocean currents, tides and river currents may deflect a sailing vessel from its desired course.[62] 152ee80cbc
open sans medium font free download