The Flemish bend known as a figure eight bend, a double figure eight bend, a rewoven figure eight is a knot for joining two ropes of similar size. A loose figure-eight knot is tied in the end of one rope; the second rope is now threaded backwards parallel to the first rope. When properly dressed, the two strands do not cross each other. Although secure, it is susceptible to jamming. If tied and stressed properly it does not need "stopper" or "safety" knots; the Flemish bend called figure-eight bend, is given in knot monographs but is used. It is bulky and bothersome to tie, not to be preferred to the following knot, made in a similar manner. List of bend knots List of knots Flemish, or double figure eight, bend animated video by Marinews Grog. "Flemish, or figure eight, bend". Animated Knots
Offset figure-eight bend
The offset figure-eight bend or flat figure-eight bend or abnormal figure-eight bend is a poor knot, implicated in the deaths of several rock climbers. The knot may invert itself under load, as shown in the figure, this can happen repeatedly; each inversion reduces the lengths of the tails. If the tails are used up the knot comes undone. More secure knots for this purpose are the Flemish bend, offset overhand bend, or double fisherman's knot
The stevedore knot is a stopper knot tied near the end of a rope. It is more bulky and less prone to jamming than the related figure-eight knot; the bight is given one more half turn than in the former knot, before the end is stuck. There is a lack of consensus among knot experts regarding the origin of the name. Many sources, including The Ashley Book of Knots, suggest the knot was used by stevedores in their work loading and unloading ships. To raise and lower cargo they used large blocks and these required a larger stopper knot to prevent the line from running through the block. However, in The Art of Knotting & Splicing, Cyrus Day disagrees, stating "the name originated in a pamphlet issued about 1890 by the C. W. Hunt Company, which sold rope under the name'Stevedore', it was subsequently adopted by dictionaries, engineers' handbooks, other works of reference, it is now established in books, if not in the vocabulary of seamen." The knot is formed by following the steps to make a figure-of-eight knot, but the working end makes an additional wrap around the standing part before passing back through the initial loop in the same direction it would have for a figure-of-eight knot.
List of knots Figure-of-nine loop Weisstein, Eric W. "Stevedores Knot". MathWorld
Abseiling known as rappelling from French rapeler,'to recall' or'to pull through'), is a controlled descent off a vertical drop, such as a rock face, using a rope. This technique is used by climbers, cavers, canyoners and rescue and rope access technicians to descend cliffs or slopes when they are too steep and/or dangerous to descend without protection. Many climbers use this technique to protect established anchors from damage. Rope access technicians use this as a method to access difficult-to-reach areas from above for various industrial applications like maintenance, construction and welding. To descend safely, abseilers use a variety of techniques to increase the friction on the rope to the point where it can be controlled comfortably; these techniques range from wrapping the rope around their body to using a custom built device like a rack. Practitioners choose a technique based on speed, safety and other circumstantial concerns. In the United States, the term "rappelling" is used nearly exclusively.
In the United Kingdom, both terms are understood, but "abseilling" is preferred. In Australia, New Zealand and Canada, the two terms are used interchangably. Globally, the term "rappelling" appears in books written in English more than "abseiling"; the origin of the term rappel in reference to the technique is attributed by Roger Frison-Roche circa 1944. Frison in turn attributed the techinique of abseiling to Jean Charlet-Straton, a Chamonix guide who lived from 1840–1925. Charlet devised the technique during a failed solo attempt of Petit Dru in 1876. After many attempts, some of them solo, he managed to reach the summit of the Petit Dru in 1879 in the company of two other hired Chamonix guides, Prosper Payot and Frédéric Folliguet. During that ascent, Charlet mastered the technique. Ropes: Static rope is ideal, but dynamic rope is used. Anchors: Usually constructed from trees, ice or rock features, using webbing/cordellete, or rock climbing equipment; some areas have fixed anchors such as pitons.
A descender: A friction device or friction hitch that allows rope to be played out in a controlled fashion, under load, with a minimal effort by the person controlling it. Climbing harness: Fixed around the waist or whole body used to secure the descender. Fit is important to prevent suspension trauma. Safety back-up: Typically a friction hitch such as a prusik, Klemheist knot, or autoblock knot wrapped around the rope as to prevent uncontrolled descents. Helmets: Used to protect the head from bumps and falling rocks. Gloves: Used to protect hands from the rope and from colliding with the wall. May increase the risk of accident by becoming caught in the descender. Boots or climbing shoes: Used to increase friction against the rock Knee-pads Abseiling is used in a number of applications, including: Climbing - for returning to the base of a climb or to a point where one can try a new route. Recreation Canyoning - to descend tall waterfalls and/or cliffs. Mountaineering Caving and speleology - where underground pitches need to be accessed.
Adventure racing Industrial/commercial applications - to access parts of structures or buildings so as to perform maintenance, cleaning or construction Access to wildfires. Confined spaces access - e.g. ballast tanks, manholes Rescue applications - used to access injured people on or nearby cliffs. Military applications - tactical heliborne insertion of troops, including special forces, into the battlefield close to the objective when proper landing zones are not available. Australian rappel — Used in the military; the abseiler descends facing downwards allowing them to see. Tandem or spider abseiling — Used in climbing. Involves two climbers descending on the same belay device; this is useful in rescue situations when one of the climbers is incapacitated or the descent needs to be done quickly. The set-up is similar to a regular rappelling, with the incapacitated climber suspended from the descender. Simul-rappelling or rappelling — Used in climbing and canyoning. Two climbers descend on the same length of rope, where one climber’s weight counterbalances the other.
The technique is considered less safe than the regular rappelling. This is common in places like the Needles of South Dakota’s Black Hills. Counterbalance abseiling — Used in climbing; this rescue technique is used by a leader to reach an injured second. The leader abseils off on one strand of rope, using the incapacitated second's weight on the other strand of the rope as a counterbalance. Releasable abseil — Used by guides; this safety technique allows a leader to descend with inexperienced abseilers. A rope about twice the length of the descent is anchored with a munter mule hitch; the client descends on a single isolated strand of the rope. If the client becomes stuck halfway down the guide will be able to unlock the other strand and lower the client to the ground using the hitch as a belay device; this could be useful if the client gets clothing or hair entangled in the descender. Classical, e.g. the Dülfersitz — Used in emergencies. These technique are more dangerous than modern alternatives and only used when no other option is available.
They involve descending without aid of mechanical devices, by wrapping the rope around the body, were used before the advent of harnesses and hardware. South African classical abseil — Used in emergencies; this is a
Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water, on ice or on land over a chosen course, part of a larger plan of navigation. A course defined with respect to the true wind direction is called a point of sail. Conventional sailing craft cannot derive power from sails on a point of sail, too close into the wind. On a given point of sail, the sailor adjusts the alignment of each sail with respect to the apparent wind direction to mobilize the power of the wind; the forces transmitted via the sails are resisted by forces from the hull and rudder of a sailing craft, by forces from skate runners of an iceboat, or by forces from wheels of a land sailing craft to allow steering the course. In the 21st century, most sailing represents a form of sport. Recreational sailing or yachting can be divided into cruising. Cruising can include extended offshore and ocean-crossing trips, coastal sailing within sight of land, daysailing; until the mid of the 19th century, sailing ships were the primary means for marine commerce, this period is known as Age of Sail.
Throughout history sailing has been instrumental in the development of civilization, affording humanity greater mobility than travel over land, whether for trade, transport or warfare, the capacity for fishing. The earliest representation of a ship under sail appears on a painted disc found in Kuwait dating between 5500 and 5000 BCE. Polynesian oceanfarers traveled vast distances of open ocean in outrigger canoes using navigation methods such as stick charts. Advances in sailing technology from the Middle Ages onward enabled Arab, Chinese and European explorers to make longer voyages into regions with extreme weather and climatic conditions. There were improvements in sails and rigging. From the 15th century onwards, European ships went further north, stayed longer on the Grand Banks and in the Gulf of St. Lawrence, began to explore the Pacific Northwest and the Western Arctic. Sailing has contributed to many great explorations in the world. According to Jett, the Egyptians used a bipod mast to support a sail that allowed a reed craft to travel upriver with a following wind, as late as 3,500 BCE.
Such sails evolved into the square-sail rig. Such rigs could not sail much closer than 80° to the wind. Fore-and-aft rigs appear to have evolved in Southeast Asia—dates are uncertain—allowing for rigs that could sail as close as 60–75° off the wind; the physics of sailing arises from a balance of forces between the wind powering the sailing craft as it passes over its sails and the resistance by the sailing craft against being blown off course, provided in the water by the keel, underwater foils and other elements of the underbody of a sailboat, on ice by the runners of an ice boat, or on land by the wheels of a sail-powered land vehicle. Forces on sails depend on the speed and direction of the craft; 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 apparent wind on the sail creates a total aerodynamic force, which may be resolved into drag—the force component in the direction of the apparent wind—and lift—the force component normal to the apparent wind.
Depending on the alignment of the sail with the apparent wind, lift or drag may be the predominant propulsive component. Depending on the angle of attack of a set of sails with respect to the apparent wind, each sail is providing motive force to the sailing craft either from lift-dominant attached flow or drag-dominant separated flow. Additionally, sails may interact with one another to create forces that are different from the sum of the individual contributions each sail, when used alone; the term "velocity" refers both to direction. As applied to wind, apparent wind velocity is the air velocity acting upon the leading edge of the most forward sail or as experienced by instrumentation or crew on a moving sailing craft. In nautical terminology, wind speeds are expressed in knots and wind angles in degrees. All sailing craft reach a constant forward velocity for a given true wind velocity and point of sail; the craft's point of sail affects its velocity for a given true wind velocity. Conventional sailing craft cannot derive power from the wind in a "no-go" zone, 40° to 50° away from the true wind, depending on the craft.
The directly downwind speed of all conventional sailing craft is limited to the true wind speed. As a sailboat sails further from the wind, the apparent wind becomes smaller and the lateral component becomes less. In order to act like an airfoil, the sail on a sailboat is sheeted further out as the course is further off the wind; as an iceboat sails further from the wind, the apparent wind increases and the boat speed is highest on the broad reach. In order to act like an airfoil, the sail on an iceboat is sheeted in for all three points of sail. Lift on a sail, acting as an airfoil, occurs in a direction perpendicular to the incident airstream and is a result of pressure differences between the windward and leeward surfaces and depends on angle of attack, sail shape, air density, speed of the apparent wind; the lift force results from the average pressure on the windward surface of the sail being higher than the ave
Rock climbing is a sport in which participants climb up, down or across natural rock formations or artificial rock walls. The goal is to reach the summit of a formation or the endpoint of a pre-defined route without falling. Professional rock climbing competitions have the objectives of either completing the route in the quickest possible time or attaining the farthest point on an difficult route. Due to the length of time and extended endurance required, because accidents are most to happen on the descent, rock climbers do not climb back down the route, or "downclimb" on the larger multiple pitch class III–IV, or multi-day grade IV–VI climbs. Rock climbing is a physically and mentally demanding sport, one that tests a climber's strength, endurance and balance along with mental control, it can be a dangerous activity and knowledge of proper climbing techniques and use of specialized climbing equipment is crucial for the safe completion of routes. Because of the wide range and variety of rock formations around the world, rock climbing has been separated into several different styles and sub-disciplines, such as scrambling, another activity involving the scaling of hills and similar formations, differentiated by rock climbing's sustained use of hands to support the climber's weight as well as to provide balance.
Paintings dating from 200 BC show Chinese men rock climbing. In early America, the cliff-dwelling Anasazi in the 12th century are thought to have been excellent climbers. Early European climbers used rock climbing techniques as a skill required to reach the summit in their mountaineering exploits. In the 1880s, European rock climbing became an independent pursuit outside of mountain climbing. Although rock climbing was an important component of Victorian mountaineering in the Alps, it is thought that the sport of rock climbing began in the last quarter of the nineteenth century in various parts of Europe. Rock climbing evolved from an alpine necessity to a distinct athletic activity. Aid climbing, climbing using equipment that acts as artificial handhold or footholds, became popular during the period 1920–1960, leading to ascents in the Alps and in Yosemite Valley that were considered impossible without such means. However, climbing techniques and ethical considerations have evolved steadily.
Today, free climbing, climbing using holds made of natural rock while using gear for protection and not for upward movement, is the most popular form of the sport. Free climbing has since been divided into several sub-styles of climbing dependent on belay configuration. Over time, grading systems have been created in order to compare more the relative difficulties of the rock climbs. In How to Rock Climb, John Long notes that for moderately skilled climbers getting to the top of a route is not enough. Within free climbing, there are distinctions given to ascents: on-sight and redpoint. To on-sight a route is to ascend the wall without aid or any foreknowledge, it is considered the way to climb with the most style. Flashing is similar to on-sighting, except that the climber has previous information about the route including talking about the beta with other climbers. Redpointing means to make a free ascent of the route after having first tried it. Style is up to each individual climber and among climbers the verbiage and definitions can differ.
Most of the climbing done in modern times is considered free climbing—climbing using one's own physical strength, with equipment used as protection and not as support—as opposed to aid climbing, the gear-dependent form of climbing, dominant in the sport's earlier days. Free climbing is divided into several styles that differ from one another depending on the choice of equipment used and the configurations of their belay and anchor systems; as routes get higher off the ground, the increased risk of life-threatening injuries necessitates additional safety measures. A variety of specialized climbing techniques and climbing equipment exists to provide that safety. Climbers will work in pairs and utilize a system of ropes and anchors designed to catch falls. Ropes and anchors can be configured in different ways to suit many styles of climbing, roped climbing are thus divided into further sub-types that vary based on how their belay systems are set up. Speaking, beginners will start with top roping and/or easy bouldering and work their way up to lead climbing and beyond.
Still the most popular method of climbing big walls, aid climbers make progress up a wall by placing and weighting gear, used directly to aid ascent and enhance safety. This form of climbing is used when ascent is too technically difficult or impossible for free climbing; the most used method to ascend climbs refers to climbs where the climber's own physical strength and skill are relied on to accomplish the climb. Free climbing may rely on top rope belay systems, or on lead climbing to establish protection and the belay stations. Anchors and protection are used to back up the climber and are passive as opposed to active ascending aids. Subtypes of free climbing are trad sport climbing. Free climbing is done as "clean lead" meaning no pitons or pins are used as protection. Climbing on short, low routes without the use of the safety rope, typical of most other styles. Protection, if used at all consists of a cushioned bouldering pad below the route and a spotter, a person who watches from below and directs the fall of the climber away from hazardous areas.
Bouldering may be an arena for intense and safe competition, resulting in exceptionally high diffic
Heraldry is a broad term, encompassing the design and study of armorial bearings, as well as related disciplines, such as vexillology, together with the study of ceremony and pedigree. Armory, the best-known branch of heraldry, concerns the design and transmission of the heraldic achievement; the achievement, or armorial bearings includes a coat of arms on an shield and crest, together with any accompanying devices, such as supporters, heraldic banners, mottoes. Although the use of various devices to signify individuals and groups goes back to antiquity, both the form and use of such devices varied and the concept of regular, hereditary designs, constituting the distinguishing feature of heraldry, did not develop until the High Middle Ages, it is often that the use of helmets with face guards during this period made it difficult to recognize one's commanders in the field when large armies gathered together for extended periods, necessitating the development of heraldry as a symbolic language but there is little actual support for this view.
The beauty and pageantry of heraldic designs allowed them to survive the gradual abandonment of armour on the battlefield during the seventeenth century. Heraldry has been described poetically as "the handmaid of history", "the shorthand of history", "the floral border in the garden of history". In modern times, individuals and private organizations, cities and regions use heraldry and its conventions to symbolize their heritage and aspirations. Various symbols have been used to represent groups for thousands of years; the earliest representations of distinct persons and regions in Egyptian art show the use of standards topped with the images or symbols of various gods, the names of kings appear upon emblems known as serekhs, representing the king's palace, topped with a falcon representing the god Horus, of whom the king was regarded as the earthly incarnation. Similar emblems and devices are found in ancient Mesopotamian art of the same period, the precursors of heraldic beasts such as the griffin can be found.
In the Bible, the Book of Numbers refers to the standards and ensigns of the children of Israel, who were commanded to gather beneath these emblems and declare their pedigrees. The Greek and Latin writers describe the shields and symbols of various heroes, units of the Roman army were sometimes identified by distinctive markings on their shields; until the nineteenth century, it was common for heraldic writers to cite examples such as these, metaphorical symbols such as the "Lion of Judah" or "Eagle of the Caesars" as evidence of the antiquity of heraldry itself. The Book of Saint Albans, compiled in 1486, declares that Christ himself was a gentleman of coat armour, but these fabulous claims have long since been dismissed as the fantasy of medieval heralds, for there is no evidence of a distinctive symbolic language akin to that of heraldry during this early period. The medieval heralds devised arms for various knights and lords from history and literature. Notable examples include the toads attributed to Pharamond, the cross and martlets of Edward the Confessor, the various arms attributed to the Nine Worthies and the Knights of the Round Table.
These too are now regarded as a fanciful invention, rather than evidence of the antiquity of heraldry. The development of the modern heraldic language cannot be attributed to a single individual, time, or place. Although certain designs that are now considered heraldic were evidently in use during the eleventh century, most accounts and depictions of shields up to the beginning of the twelfth century contain little or no evidence of their heraldic character. For example, the Bayeux Tapestry, illustrating the Norman invasion of England in 1066, commissioned about 1077, when the cathedral of Bayeux was rebuilt, depicts a number of shields of various shapes and designs, many of which are plain, while others are decorated with dragons, crosses, or other heraldic figures, yet no individual is depicted twice bearing the same arms, nor are any of the descendants of the various persons depicted known to have borne devices resembling those in the tapestry. An account of the French knights at the court of the Byzantine emperor Alexius I at the beginning of the twelfth century describes their shields of polished metal, utterly devoid of heraldic design.
A Spanish manuscript from 1109 describes both plain and decorated shields, none of which appears to have been heraldic. The Abbey of St. Denis contained a window commemorating the knights who embarked on the Second Crusade in 1147, was made soon after the event. In England, from the time of the Norman conquest, official documents had to be sealed. Beginning in the twelfth century, seals assumed a distinctly heraldic character. A notable example of an early armorial seal is attached to a charter granted by Philip I, Count of Flanders, in 1164. Seals from the latter part of the eleventh and early twelfth centuries show no evidence of heraldic symbolism, but by t