In watercraft A watercraft is a vehicle, vessel or craft designed to move across water, including saltwater and freshwater, for pleasure, recreation, physical exercise, commerce, transport and military missions. It is derived from the term "craft" which was used as term to describe all types of water going vessels. (The term craft has since been, a racing shell (also referred to as just a fine boat (UK) or just shell) is an extremely narrow, and often disproportionately long, rowing boat Watercraft rowing is the act of propelling a boat using the motion of oars in the water. The difference between paddling and rowing is that with rowing the oars have a mechanical connection with the boat whereas with paddling the paddles are hand-held with no mechanical connection specifically designed for racing Rowing is a sport in which athletes race against each other on rivers, on lakes or on the ocean, depending upon the type of race and the discipline. The boats are propelled by the reaction forces on the oar blades as they are pushed against the water. The sport can be both recreational, focusing on learning the techniques required, and competitive or exercise. It is outfitted with long oars, outriggers In an outrigger canoe or bangka and in sailboats such as the proa, an outrigger is a thin, long, solid, hull used to stabilise an inherently unstable main hull. The outrigger is positioned rigidly and parallel to the main hull so that the main hull is less likely to capsize. If only one outrigger is used on a vessel, its weight reduces the to hold the oarlocks away for the boat, and sliding seats. The boat's long length and semicircular cross-section reduce drag to a minimum. This makes the boat both fast and unstable. It must be actively balanced by the rowers to avoid tipping. Being able to balance, or "set" the boat while putting maximum effort into the oars is therefore an essential skill of rowing.
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History
The racing shell evolved from the simple working rowboat Watercraft rowing is the act of propelling a boat using the motion of oars in the water. The difference between paddling and rowing is that with rowing the oars have a mechanical connection with the boat whereas with paddling the paddles are hand-held with no mechanical connection. Boats with longer hulls A hull is the watertight body of a ship or boat. Above the hull comes the superstructure and deckhouse. The line where the hull meets the water surface is called the waterline and narrower in beam The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position. Typical length-to-beam ratios for small sailboats are from 2:1 (dinghies were developed in the early 1800s specifically for team racing. These dedicated boats were the first boats that could be called racing shells, and they have since evolved into the highly specialized forms used today.
Riggers
A narrower boat provides a sharper angle to the bow and a smaller cross-sectional area reducing drag In fluid dynamics, drag refers to forces that oppose the relative motion of an object through a fluid (a liquid or gas). Drag forces act in a direction opposite to the oncoming flow velocity. Unlike other resistive forces such as dry friction, which is nearly independent of velocity, drag forces depend on velocity and wave drag Wave making resistance is a form of drag that affects surface watercraft, such as boats and ships, and reflects the energy required to push the water out of the way of the hull. This energy goes into creating the wake, and avoiding hull speed Hull speed, sometimes referred to as displacement speed, is a rule of thumb used to provide an approximate maximum efficient speed for a hull. It is only ever an approximation and only applies where the hull is a fairly traditional displacement design. It is usually described as a speed corresponding to a speed-length ratio of between 1.34 and 1.51 limitations at race speed. The first racing shells, while narrower than working rowboats, were limited by the width necessary to mount the oarlocks on the boat's sides ("gunwales The gunwale is a nautical term describing the top edge of the side of a boat"). By attaching riggers to the gunwales, the oarlocks could be placed farther out, two things happened: oars got much longer, providing more length to the strokes, and hulls got narrower, until they were as narrow as it was possible while still retain sufficient buoyancy and balance.
Materials
University of Vermont 8+ oar shellOriginally made from lapstrake wood Wood is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression. In the strict sense wood is produced as secondary xylem in the stems of trees (and other woody plants). In a living tree it transfers water and nutrients to the leaves and other growing tissues, and has a support function,, shells are now almost always made from a composite material Composite materials are engineered materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct on a macroscopic level within the finished structure for strength and weight advantages. The first composite shells were made from a form of papier-mâché Papier-mâché , commonly called paper-mâché, is a construction material that consists of pieces of paper, sometimes reinforced with textiles, stuck together using a wet paste (e.g., glue, starch, or wallpaper adhesive). The crafted object becomes solid when the paste dries and became popular in the 1870s. Modern shells are usually made of carbon-fibre reinforced plastic Carbon fiber-reinforced polymer or carbon fiber-reinforced plastic , is a very strong, light, and expensive composite material or fiber-reinforced polymer. Similar to fiberglass (glass reinforced polymer), the composite material is commonly referred to by the name of its reinforcing fibers (carbon fiber). The polymer is most often epoxy, but other in a honeycomb A honeycomb is a mass of hexagonal wax cells built by commercial and wild honey bees in their nests to contain their larvae and stores of honey and pollen structure. They are manufactured by either cold laying up of the carbon, which is then left to set, or by using heat curing, which ensures that the carbon fibre composite is properly set. The best shells are characterized by their "stiffness", as the lack of flexing means none of the force exerted by the rower is wasted in twisting the boat.
Sliding seats
A rower on a fixed seat is limited in the amount of power he can apply to the oars by the strength in his upper body and the distance he can pull the oars on each stroke. After riggers were added to the shell allowing the use of longer oars, rowers took advantage by taking longer strokes and using their legs during the stroke. At first, the athletes wore trousers with wear resistant leather Leather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry bottoms covered in grease and the shells had concave, longitudinal seats. The athletes could then use their legs to slide along the seat, adding the power of their legs and letting them greatly lengthen the stroke. This eventually lead to the modern sliding seat, mounted on rollers, which allows nearly frictionless movement of the rower's body.
Boat classification
There are a large number of different types of boats. They are classified using:
- Number of rowers. In all forms of modern competition the number is either 1, 2, 4, or 8. Although they are very rare, boats for other numbers of rowers do exist (such as the 24 person Stämpfli Express). In the 1800s, there were often races with 6, 10 and 12 rowers per boat.[citation needed]
- Position of coxswain. Boats are either coxless, bow-coxed (also called bowloaders A bowloader is a crew shell in which the coxswain lies semi-supine in the bow, as opposed to the normal seated position at the stern. Bowloaders are often seen as coxed fours and also coxed pairs. Although a small number of bowloader eights exist, the larger boat's momentum means that a coxswain lying in the bows could be injured in a collision if), or stern-coxed. In coxless ("straight") boats, a steersman is responsible for steering by either use of a mechanism connecting one of his shoes by wire to the rudder--the swiveling of the shoe turns the rudder, or by using a hand controlled string, called a tiller rope, which is parallel to the gunwhales or the boat, and controls the rudder in a similar fashion. Singles, doubles, and quads do not employ a rudder in competition; the oarsmen steer by increasing or decreasing pressure on one scull or the other. In competition, bow- and stern-coxed boats may race one another.
Although sculling and sweep boats are generally identical to each other (except having different riggers), they are referred to using different names:
- Sweep: straight pair (2-), coxed pair (2+), straight four (4-), coxed four (4+), eight (8+) (always coxed)
- Sculling: single (1x), double (2x), quad (4x), octuple (8x) (very rare, and always coxed)
References
- A history of paper boats, including the paper racing shell
- History of MIT Crew: Chapter 8, which covers the evolution of the rowing shell
Categories: Rowing Categories: Boat racing | Commonwealth Games sports | Endurance sports | Human-powered vehicles | Olympic sports | Water sports | Boat types
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