Misplaced Pages

#118881

62-516: Centurion Boats was founded by Rick and Pam Lee. They acquired the trade name from a Salt Lake City company, and took their first order by phone in 1976. The first products were inboard ski boats, which were produced in a leased 10,000 square foot facility in Southern California. In 1986 the first V-Drive ski boat was brought to market. As business increased, the facility was expanded to 121,000 sq feet, set on about six acres, including

124-461: A boat, but can also be towed by cable systems and winches, and be pulled by other motorized vehicles like personal watercraft, cars, trucks, and all-terrain vehicles. The gear and wakeboard boat used are often personalized to each rider's liking. Though natural watercourses such as rivers, lakes and areas of open water are generally used in wakeboarding, it is possible to wakeboard in unconventional locations, such as flooded roads and car parks, using

186-441: A car as the towing vehicle. Wakeboarding is done for pleasure and competition, ranging from freestyle wakeboarding and wakeboard parks to wakeboard competitions at the X Games , WWA Wakeboard World Championships, or similar events. Though it had an obscure start, it is now the world's fastest-growing water sport. The sport that would later become wake boarding began as water-skiing with mono water skis (single water skis) in

248-515: A high chemical resistance. Polypropylene is the second-most widely produced commodity plastic (after polyethylene ). Phillips Petroleum chemists J. Paul Hogan and Robert Banks first demonstrated the polymerization of propylene in 1951. The stereoselective polymerization to the isotactic was discovered by Giulio Natta and Karl Rehn in March 1954. This pioneering discovery led to large-scale commercial production of isotactic polypropylene by

310-638: A melting point of 130 °C (266 °F). Below 0 °C, PP becomes brittle. The thermal expansion of PP is significant, but somewhat less than that of polyethylene. Propylene molecules prefer to join together "head-to-tail", giving a chain with methyl groups on every other carbon, but some randomness occurs. Polypropylene at room temperature is resistant to fats and almost all organic solvents , apart from strong oxidants. Non-oxidizing acids and bases can be stored in containers made of PP. At elevated temperature, PP can be dissolved in nonpolar solvents such as xylene , tetralin and decalin . Due to

372-525: A modifier. The catalysts are differentiated depending on the procedure used for fashioning catalyst particles from MgCl 2 and depending on the type of organic modifiers employed during catalyst preparation and use in polymerization reactions. Two most important technological characteristics of all the supported catalysts are high productivity and a high fraction of the crystalline isotactic polymer they produce at 70–80 °C under standard polymerization conditions. Commercial synthesis of isotactic polypropylene

434-402: A range, so the melting point is determined by finding the highest temperature of a differential scanning calorimetry chart. Perfectly isotactic PP has a melting point of 171 °C (340 °F). Commercial isotactic PP has a melting point that ranges from 160 to 166 °C (320 to 331 °F), depending on atactic material and crystallinity. Syndiotactic PP with a crystallinity of 30% has

496-716: A series of licensed waterskiing boats. For several years Centurion sponsored the Watkins Glen sprint racecourse, leading to the unusual title "Centurion Boats at the Glen". In 2015 the Correct Craft company bought a majority interest in Centurion Boats. As of 2013, the company's best-selling line was the Centurion Enzo, a V-Drive tow boat geared towards producing Wakesurfing waves. That year an Enzo

558-406: A smoother ride. The wake board rope has advanced over the years with improvements in the material makeup. When wakeboarding first started, wakeboarders used ski rope, which was made with stretchy cloth or plastic ropes. The latter soon grew in popularity, and a braided rope made out of polypropylene was eventually introduced. A few years later , a rope that was less stretchy was invented that gave

620-444: A stiffer material that is more resistant to creep than both atactic polypropylene and polyethylene. The density of PP is between 0.895 and 0.93 g/cm . Therefore, PP is the commodity plastic with the lowest density. With lower density, moldings parts with lower weight and more parts of a certain mass of plastic can be produced. Unlike polyethylene, crystalline and amorphous regions differ only slightly in their density. However,

682-442: A test lake for research and development. Centurion later manufactured mainly boats designed for Wakeboarding and Wakesurfing . In 1990 the company developed C.A.T. fins, and by 1992 they had developed a computerized management system to monitor and control boats' features and performance. In 1995 Centurion began manufacturing 'The Wave', a boat specifically designed to create large wakes for Wakeboarding and Wakesurfing. By 1997

SECTION 10

#1732802508119

744-490: A wide range of useful products, such as face masks, filters, diapers and wipes. The most common shaping technique is injection molding , which is used for parts such as cups, cutlery, vials, caps, containers, housewares, and automotive parts such as batteries. The related techniques of blow molding and injection-stretch blow molding are also used, which involve both extrusion and molding. The large number of end-use applications for polypropylene are often possible because of

806-402: Is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene . Polypropylene belongs to the group of polyolefins and is partially crystalline and non-polar . Its properties are similar to polyethylene , but it is slightly harder and more heat-resistant. It is a white, mechanically rugged material and has

868-501: Is a colorless, cloudy material and can be used between −15 and +120 °C. Atactic polypropylene is used as a sealant, as an insulating material for automobiles and as an additive to bitumen . Polypropylene copolymers are in use as well. A particularly important one is polypropylene random copolymer ( PPR or PP-R ), a random copolymer with polyethylene used for plastic pipework . Polypropylene random crystallinity temperature ( PP-RCT ), also used for plastic pipework ,

930-492: Is a measure of molecular weight of polypropylene. The measure helps to determine how easily the molten raw material will flow during processing. Polypropylene with higher MFR will fill the plastic mold more easily during the injection or blow-molding production process. As the melt flow increases, however, some physical properties, like impact strength, will decrease. There are three general types of polypropylene: homopolymer , random copolymer, and block copolymer . The comonomer

992-410: Is a new form of this plastic. It achieves higher strength at high temperature by β- crystallization . Polypropylene is liable to chain degradation from exposure to temperatures above 100 °C. Oxidation usually occurs at the tertiary carbon centers leading to chain breaking via reaction with oxygen . In external applications, degradation is evidenced by cracks and crazing . It may be protected by

1054-407: Is as biaxially oriented polypropylene (BOPP). These BOPP sheets are used to make a wide variety of materials including clear bags . When polypropylene is biaxially oriented, it becomes crystal clear and serves as an excellent packaging material for artistic and retail products. Polypropylene, highly colorfast, is widely used in manufacturing carpets, rugs and mats to be used at home. Polypropylene

1116-413: Is easy to coat, print and laminate to give the required appearance and properties for use as a packaging material. This process is normally called converting . It is normally produced in large rolls which are slit on slitting machines into smaller rolls for use on packaging machines. BOPP is also used for stickers and labels in addition to OPP. It is non-reactive, which makes BOPP suitable for safe use in

1178-456: Is extruded and stretched in both the machine direction and across machine direction it is called biaxially oriented polypropylene . Two methods are widely used for producing BOPP films, namely, a bi-directional stenter process or a double-bubble blown film extrusion process. Biaxial orientation increases strength and clarity. BOPP is widely used as a packaging material for packaging products such as snack foods, fresh produce and confectionery. It

1240-423: Is given as 185 to 220 °C, the density as 0.936 to 0.946 g·cm . The β-modification is in comparison somewhat less ordered, as a result of which it forms faster and has a lower melting point of 170 to 200 °C. The formation of the β-modification can be promoted by nucleating agents, suitable temperatures and shear stress. The γ-modification is hardly formed under the conditions used in industry and

1302-447: Is made with two types of Ziegler-Natta catalysts. The first group of the catalysts encompasses solid (mostly supported) catalysts and certain types of soluble metallocene catalysts. Such isotactic macromolecules coil into a helical shape; these helices then line up next to one another to form the crystals that give commercial isotactic polypropylene many of its desirable properties. Modern supported Ziegler-Natta catalysts developed for

SECTION 20

#1732802508119

1364-427: Is manufactured using melt processing with either chemical or physical blowing agents. Expansion of PP in solid state, due to its highly crystalline structure, has not been successful. In this regard, two novel strategies were developed for expansion of PP. It was observed that PP can be expanded to make EPP through controlling its crystalline structure or through blending with other polymers. When polypropylene film

1426-457: Is poorly understood. The mesomorphic modification, however, occurs often in industrial processing, since the plastic is usually cooled quickly. The degree of order of the mesomorphic phase ranges between the crystalline and the amorphous phase, its density is with 0.916 g·cm comparatively. The mesomorphic phase is considered as cause for the transparency in rapidly cooled films (due to low order and small crystallites). Syndiotactic polypropylene

1488-518: Is typically used with ethylene . Ethylene-propylene rubber or EPDM added to polypropylene homopolymer increases its low temperature impact strength. Randomly polymerized ethylene monomer added to polypropylene homopolymer decreases the polymer crystallinity, lowers the melting point and makes the polymer more transparent. [REDACTED] Polypropylene can be categorized as atactic polypropylene (aPP), syndiotactic polypropylene (sPP) and isotactic polypropylene (iPP). In case of atactic polypropylene,

1550-416: Is usually carried out either in the medium of liquid propylene or in gas-phase reactors. Commercial synthesis of syndiotactic polypropylene is carried out with the use of a special class of metallocene catalysts. They employ bridged bis-metallocene complexes of the type bridge-(Cp 1 )(Cp 2 )ZrCl 2 where the first Cp ligand is the cyclopentadienyl group, the second Cp ligand is the fluorenyl group, and

1612-548: The Italian firm Montecatini from 1957 onwards. Syndiotactic polypropylene was also first synthesized by Natta. Interest in polypropylene development is ongoing to the present. For example, making polypropylene from bio-based resources is a topic of interest in the 21st century. Polypropylene is in little aspects similar to polyethylene , especially in solution behavior and electrical properties. The methyl group improves mechanical properties and thermal resistance, although

1674-703: The USA around 1950. The main difference between mono water skis and contemporary wake boards is the shape of the board and the stance. Wake surfing - using surfboards as mono water skis - began picking up traction around 1964, where it was seen as an "exciting new sport that's soon going to sweep the waterways." Although surfboards were originally used, boards without straps or bindings were first seen in New Zealand with boards called "skurfboards". Eventually, wake boards with bindings or straps were sold in Australia under

1736-430: The aPP obtained this way is not completely amorphous but can still contain 15% crystalline parts. Atactic polypropylene can also be produced selectively using metallocene catalysts, atactic polypropylene produced this way has a considerably higher molecular weight. Atactic polypropylene has lower density, melting point and softening temperature than the crystalline types and is tacky and rubber-like at room temperature. It

1798-509: The ability to tailor grades with specific molecular properties and additives during its manufacture. For example, antistatic additives can be added to help polypropylene surfaces resist dust and dirt. Many physical finishing techniques can also be used on polypropylene, such as machining . Surface treatments can be applied to polypropylene parts in order to promote adhesion of printing ink and paints. Expanded Polypropylene (EPP) has been produced through both solid and melt state processing. EPP

1860-420: The amount of fins they have which can be up to 5. Fins will make it easier to turn and stay level for beginners but should be removed for tricks and spins since they can make it easier to catch an edge on a jump or during a spin. [1] Another part of the wakeboard itself to consider is the size of the board and the material, which are usually a wood or foam core with a fiber glass or carbon fiber coating. [2] At

1922-638: The bridge between the two Cp ligands is -CH 2 -CH 2 -, >SiMe 2 , or >SiPh 2 . These complexes are converted to polymerization catalysts by activating them with a special organoaluminium co-catalyst, methylaluminoxane (MAO). Atactic polypropylene is an amorphous rubbery material. It can be produced commercially either with a special type of supported Ziegler-Natta catalyst or with some metallocene catalysts. Melting process of polypropylene can be achieved via extrusion and molding . Common extrusion methods include production of melt-blown and spun-bond fibers to form long rolls for future conversion into

Centurion Boats - Misplaced Pages Continue

1984-401: The chemical resistance decreases. The properties of polypropylene depend on the molecular weight and molecular weight distribution, crystallinity, type and proportion of comonomer (if used) and the iso tacticity . In isotactic polypropylene, for example, the methyl groups are oriented on one side of the carbon backbone. This arrangement creates a greater degree of crystallinity and results in

2046-512: The density of polyethylene can significantly change with fillers. The Young's modulus of PP is between 1300 and 1800 N/mm². Polypropylene is normally tough and flexible, especially when copolymerized with ethylene . This allows polypropylene to be used as an engineering plastic , competing with materials such as acrylonitrile butadiene styrene (ABS). Polypropylene is reasonably economical. Polypropylene has good resistance to fatigue . The melting point of polypropylene occurs in

2108-414: The heat in an autoclave . Its heat resistance also enables it to be used as the manufacturing material of consumer-grade kettles . Food containers made from it will not melt in the dishwasher, and do not melt during industrial hot filling processes. For this reason, most plastic tubs for dairy products are polypropylene sealed with aluminum foil (both heat-resistant materials). After the product has cooled,

2170-660: The hinge to maximise strength. Polypropylene is used in the manufacturing of piping systems, both ones concerned with high purity and ones designed for strength and rigidity (e.g., those intended for use in potable plumbing, hydronic heating and cooling, and reclaimed water ). This material is often chosen for its resistance to corrosion and chemical leaching, its resilience against most forms of physical damage, including impact and freezing, its environmental benefits, and its ability to be joined by heat fusion rather than gluing. Many plastic items for medical or laboratory use can be made from polypropylene because it can withstand

2232-691: The human body as implantable mesh devices. The degraded material forms a tree bark-like layer at the surface of mesh fibers. PP can be made translucent when uncolored but is not as readily made transparent as polystyrene , acrylic , or certain other plastics. It is often opaque or colored using pigments. Polypropylene is produced by the chain-growth polymerization of propene : [REDACTED] The industrial production processes can be grouped into gas phase polymerization, bulk polymerization and slurry polymerization. All state-of-the-art processes use either gas-phase or bulk reactor systems. The properties of PP are strongly affected by its tacticity ,

2294-651: The lids are often made of somewhat more flexible LDPE so they can snap onto the container to close it. Polypropylene can also be made into disposable bottles to contain liquid, powdered, or similar consumer products, although HDPE and polyethylene terephthalate are commonly also used to make bottles. Plastic pails, car batteries, wastebaskets, pharmacy prescription bottles, cooler containers, dishes and pitchers are often made of polypropylene or HDPE, both of which commonly have rather similar appearance, feel, and properties at ambient temperature. An abundance of medical devices are made from PP. A common application for polypropylene

2356-459: The material of the rope being used can make a significant difference in ride experience. The less stretch in the rope, the better it is for the rider to learn how to ride and do various tricks. Some of the best rope materials include Dyneema, Poly E, and Spectra. Each of these is known for its abrasion resistance, affordability and absorption, and durability respectively. When wakeboarding, a variety of tricks may be attempted. Most of these stem from

2418-407: The methyl group (-CH 3 ) is randomly aligned, alternating (alternating) for syndiotactic polypropylene and evenly for isotactic polypropylene. This has an impact on the crystallinity (amorphous or semi-crystalline) and the thermal properties (expressed as glass transition point T g and melting point T m ). The term tacticity describes for polypropylene how the methyl group is oriented in

2480-424: The molecular arrangement of the polymer chains. The crystalline modifications are categorized into the α-, β- and γ-modification as well as mesomorphic (smectic) forms. The α-modifications is predominant in iPP. Such crystals are built from lamellae in the form of folded chains. A characteristic anomaly is that the lame are arranged in the so-called "cross-hatched" structure. The melting point of α-crystalline regions

2542-502: The most common wakeboard styles include the continuous rocker, the three-stage rocker, the five-stage rocker, and the hybrid rocker. Rocker refers to the curve of the board from head to tail and each type of board has a different placement and amount of curve that works best for different types of rides. The presence or absence of fins on the bottom of a board can also make a drastic difference in how it rides. Beginning riders are usually better off with deeper fins. Wakeboards can also vary in

Centurion Boats - Misplaced Pages Continue

2604-555: The name "McSkis". Later, another company called "Skurfer" was founded by Tony Finn in 1985, named as such due to the board being a cross of a surfboard and a water ski . The first board made in the early 1990's was the Hyper lite board by the O’Brien company, a water ski manufacturer who marketed the board as a “compression-molded neutral-buoyancy wake board.” This was followed by a variety of boards that are curvier and more compact, creating

2666-484: The new UCS construction system was introduced, eliminating wood from the boat structure. In 2003, Centurion introduced the Tsunami model, a cabin cruiser with a large fuel tank. Centurion developed sideswipe exhaust in 2003. The Avalanche model for wake riding and the similar but smaller V-Drive Cyclone model were introduced in 2004. After developing VTF Fins in 2005, Centurion collaborated with NASCAR in 2007 to produce

2728-458: The orientation of the methyl groups ( CH 3 ) relative to the methyl groups in neighboring monomer units. A Ziegler–Natta catalyst is able to restrict linking of monomer molecules to a specific orientation, either isotactic, when all methyl groups are positioned at the same side with respect to the backbone of the polymer chain, or syndiotactic, when the positions of the methyl groups alternate. Commercially available isotactic polypropylene

2790-400: The other hand, lacks any regularity, which prevents it from crystallization, thereby creating an amorphous material. Isotactic polypropylene has a high degree of crystallinity , in industrial products 30–60%. Syndiotactic polypropylene is slightly less crystalline, atactic PP is amorphous (not crystalline). Is polypropylene can exist in various crystalline modifications which differ by

2852-409: The pharmaceutical and food industry. It is one of the most important commercial polyolefin films. BOPP films are available in different thicknesses and widths. They are transparent and flexible. As polypropylene is resistant to fatigue, most plastic living hinges , such as those on flip-top bottles, are made from this material. However, it is important to ensure that chain molecules are oriented across

2914-463: The polymer chain. Commercial polypropylene is usually isotactic. This article therefore always refers to isotactic polypropylene, unless stated otherwise. The tacticity is usually indicated in percent, using the isotactic index (according to DIN 16774). The index is measured by determining the fraction of the polymer insoluble in boiling heptane . Commercially available polypropylenes usually have an isotactic index between 85 and 95%. The tacticity effects

2976-412: The polymerization of propylene and other 1-alkenes to isotactic polymers usually use TiCl 4 as an active ingredient and MgCl 2 as a support. The catalysts also contain organic modifiers, either aromatic acid esters and diesters or ethers. These catalysts are activated with special co-catalysts containing an organoaluminium compound such as Al(C 2 H 5 ) 3 and the second type of

3038-443: The polymers physical properties . As the methyl group is in isotactic propylene consistently located at the same side, it forces the macromolecule in a helical shape , as also found in starch . An isotactic structure leads to a semi-crystalline polymer . The higher the isotonicity(the isotactic fraction), the greater the crystallinity, and thus also the softening point, rigidity, e-modulus and hardness. Atactic polypropylene, on

3100-461: The rider a more consistent pull on the rope, though they were heavier and larger in diameter. Modern ropes are coated with Spectra and Dyneema, which decrease the stretch and drag of the rope. When wakeboarding, a wide variety of safety equipment is used. These include life vests or other buoyancy aids which prevent water-related injuries and deaths, as they keep the wearer buoyant until they are picked up. These vests especially help in situations where

3162-487: The rider is fully upside down, as evidenced by the Raley, a trick where the rider extends their body parallel to the water bending at the knees to achieve inversion. The heel side backflip, otherwise known as a tantrum, is often regarded as the first and easiest invert to learn as an intermediate level rider. This is because the shape of the wake or the “kicker” (a type of floating ramp, used primarily at cable parks, that mimics

SECTION 50

#1732802508119

3224-484: The rider is knocked unconscious or cannot tread water. Furthermore, wakeboarders use water-resistant helmets that are able to ventilate water so that the helmets do not fill up with water. Even the length of a wakeboarder's rope is important in providing safety; if the rope is too long, a wakeboarder will land on the flat part of the wake instead of the downside, and their knees will buckle. Wakeboards themselves are also important to consider when preparing to ride. Four of

3286-405: The rider, standing on a wakeboard (a board with foot bindings), is towed behind a motorboat across its wake and especially up off the crest in order to perform aerial maneuvers. A hallmark of wakeboarding is the attempted performance of midair tricks. Wakeboarding was developed from a combination of water skiing , snowboarding and surfing techniques. The rider is usually towed by a rope behind

3348-418: The same time, the length of a wakeboarding rope will vary based on the rider's preferences. Beginner ropes usually go from about 50’ to 75’ in total length, while more advanced riders will want a rope that goes from 65’ to 85’. A longer rope may allow for more preparation and momentum before performing tricks, whereas a shorter rope may require less speed and height to travel between wakes. In addition to this,

3410-443: The shape of a wake) naturally initiates the sequence of motions that are necessary to complete the trick. There are many different ways that people are engaged in this sport. Popular brands like Byerly, Hyperlight, O'Brien and Ronix provide ever evolving technology and equipment as well as quality advice for new and seasoned riders alike. Some of these brands also have active social media presence to reach more people and get them into

3472-604: The sport. Many movements and tricks in wakeboarding bear close resemblance to moves also found in kitesurfing . This is reflected in close similarities between wakeboards and twin-tip kitesurf-boards. Wakeboarding in wake and waterski parks is thus often considered a more approachable wind condition independent alternative to kitesurfing and has seen a surge in popularity in parallel to kitesurfing, especially in densely populated areas in Europe, such as Germany. Polypropylene Polypropylene ( PP ), also known as polypropene ,

3534-527: The tertiary carbon atom, PP is chemically less resistant than PE (see Markovnikov rule ). Most commercial polypropylene is isotactic and has an intermediate level of crystallinity between that of low-density polyethylene (LDPE) and high-density polyethylene (HDPE). Isotactic & atactic polypropylene is soluble in p -xylene at 140 °C. Isotactic precipitates when the solution is cooled to 25 °C and atactic portion remains soluble in p -xylene. The melt flow rate (MFR) or melt flow index (MFI)

3596-520: The tubs are often given lids made of a less heat-resistant material, such as LDPE or polystyrene. Such containers provide a good hands-on example of the difference in modulus, since the rubbery (softer, more flexible) feeling of LDPE with respect to polypropylene of the same thickness is readily apparent. Rugged, translucent, reusable plastic containers made in a wide variety of shapes and sizes for consumers from various companies such as Rubbermaid and Sterilite are commonly made of polypropylene, although

3658-401: The use of various polymer stabilizers , including UV-absorbing additives and anti-oxidants such as phosphites (e.g. tris(2,4-di-tert-butylphenyl)phosphite ) and hindered phenols, which prevent polymer degradation . Microbial communities isolated from soil samples mixed with starch have been shown to be capable of degrading polypropylene. Polypropylene has been reported to degrade while in

3720-410: The wakeboarder adjusting their posture, edge, and distribution of weight so as to fly into the air upon hitting the wake. Various tricks include the toeside edge, the heelside edge, the ride switch, and the 180° spin. More advanced tricks call for what is known as inversion or “inverts”. An invert is considered any action where the board is above the head of the rider. This does not necessarily mean

3782-474: Was discovered much later than isotactic PP and could only be prepared by using metallocene catalysts . Syndiotactic PP has a lower melting point, with 161 to 186 °C, depending on the degree of tacticity. Atactic polypropylene is amorphous and has therefore no crystal structure. Due to its lack of crystallinity, it is readily soluble even at moderate temperatures, which allows to separate it as by-product from isotactic polypropylene by extraction . However,

SECTION 60

#1732802508119

3844-568: Was the official towboat of the World Wake Surfing Championship. Another newer model was the Avalanche C4, a V-Drive boat for both wakesurfing and wakeboarding. The Elite V C4 model is a less expensive V-Drive boat, with a narrower beam and shallower draft. The Carbon Pro is an inboard ski towboat, geared towards tournament ski competition performance. Wakeboarding Wakeboarding is a water sport in which

#118881