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Tunnel Hull
A tunnel hull is a type of boat hull that uses two typically planing hulls with a solid centre that traps air. This entrapment then creates aerodynamic lift in addition to the planing (hydrodynamic) lift from the hulls. Many times this is attributed to ground effect. Theoretical research and full-scale testing of tunnel hulls has demonstrated the dramatic contributions of 'close-proximity ground effect' on enhanced aerodynamic lift/drag in operation of performance tunnel hull designs."Secrets of Tunnel Boat Design", JDRussell,P.Eng. () Tunnel hulls are distinguishable from other catamarans by the typical close hull spacing and solid deck in between the hulls. Formula 1 powerboats have a tunnel hull catamaran design allowing them to go faster. Tunnel hulls are a common design in offshore powerboat racing. References See also * Cathedral hull * Hickman sea sled * Boston Whaler * Supercavitation propeller * Offshore Powerboat Racing Offshore powerboat racing is a type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground Effect (aircraft)
For fixed-wing aircraft, ground effect is the reduced aerodynamic drag that an aircraft's wings generate when they are close to a fixed surface.. Reduced drag when in ground effect during takeoff can cause the aircraft to "float" while below the recommended climb speed. The pilot can then fly just above the runway while the aircraft accelerates in ground effect until a safe climb speed is reached.. For rotorcraft, ground effect results in less drag on the rotor during hovering close to the ground. At high weights this sometimes allows the rotorcraft to lift off while stationary in ground effect but does not allow it to transition to flight out of ground effect. Helicopter pilots are provided with performance charts which show the limitations for hovering their helicopter in ground effect (IGE) and out of ground effect (OGE). The charts show the added lift benefit produced by ground effect. For fan- and jet-powered vertical take-off and landing (VTOL) aircraft, ground effect when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catamaran
A Formula 16 beachable catamaran Powered catamaran passenger ferry at Salem, Massachusetts, United States A catamaran () (informally, a "cat") is a multi-hulled watercraft featuring two parallel hulls of equal size. It is a geometry-stabilized craft, deriving its stability from its wide beam, rather than from a ballasted keel as with a monohull boat. Catamarans typically have less hull volume, smaller displacement, and shallower draft (draught) than monohulls of comparable length. The two hulls combined also often have a smaller hydrodynamic resistance than comparable monohulls, requiring less propulsive power from either sails or motors. The catamaran's wider stance on the water can reduce both heeling and wave-induced motion, as compared with a monohull, and can give reduced wakes. Catamarans were invented by the Austronesian peoples which enabled their expansion to the islands of the Indian and Pacific Oceans. Catamarans range in size from small sailing or rowing ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Offshore Powerboat Racing
Offshore powerboat racing is a type of racing by ocean-going powerboats, typically point-to-point racing. In most of the world, offshore powerboat racing is led by the Union Internationale Motonautique (UIM) regulated Class 1 and Powerboat P1. In the US, offshore powerboat racing is led by the APBA/UIM and consists of races hosted by Powerboat P1 USA. The sport is financed by a mixture of private funding and commercial sponsors. History of the sport In 1903, the Automobile Club of Great Britain and Ireland, and its offshoot, the Marine Motor Association organised a race of auto-boats. The winner was awarded the Harmsworth Trophy. Offshore powerboat racing was first recognised as a sport when, in 1904, a race took place from the south-eastern coast England to Calais, France. In the United States, the APBA (American Power Boat Association) was formed soon thereafter and the first U.S. recorded race was in 1911, in California. The sport increased in popularity over the next few ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathedral Hull
A cathedral hull is a hull shape used in modern boats, usually power-driven. It has sponsons which extend almost as far forward as the main hull. The airspace between the hulls may be very small or nonexistent. Depending on the proportions of the sponsons and the depth of the main hull, the cathedral hull can approach the handling characteristics of either the Hickman sea sled, or the vee hull. The naval architect first credited with the successful use of the deep-vee hull form, C. Raymond Hunt, was involved in the design of the original 13’ Boston Whaler. It is cathedral hulled forward, but nearly a flat-bottomed scow at the stern. The term "cathedral hull" refers to the resemblance of a section through an inverted boat to that of a medieval cathedral. Characteristics The cathedral hull configuration tends to result in a very broad bow; many such boats are completely rectangular. This provides the maximum cargo or working space for a given length and beam. The hull shape ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hickman Sea Sled
The Hickman Sea Sled is an inverted vee planing hull invented by Albert Hickman. The Sea Sled is a direct forerunner of the modern high speed catamaran or tunnel hull. The reduced friction is due to a "trapped" gas film between the hull surface and water. A similar effect is seen in super-cavitating torpedoes where a gas generator creates a film separation to water friction. "A new type of vessel, which promises to revolutionize water craft and which takes the same place on the water that the automobile does on land" - ''Scientific American'' 26 September 1914 See also * Cathedral hull * Boston Whaler Boston Whaler is an American boat manufacturer. It is a subsidiary of the Brunswick Boat Group, a division of the Brunswick Corporation. Boston Whalers were originally produced in Massachusetts, hence the name, but today are manufactured in Edge ... * Supercavitation propeller References * Campbell, Lorne''Innovation in Small Craft Design - A Tribute'' The Royal Institute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boston Whaler
Boston Whaler is an American boat manufacturer. It is a subsidiary of the Brunswick Boat Group, a division of the Brunswick Corporation. Boston Whalers were originally produced in Massachusetts, hence the name, but today are manufactured in Edgewater, Florida. History Richard "Dick" Fisher graduated from Harvard University in 1936. He ran a company building small, lightweight boats out of balsa wood. He designed a rowboat and got the materials to build it, but he never completed it. In the 1950s, polyurethane foam, a stiff, lightweight, buoyant material, was invented. Fisher imagined it as a replacement for the lightweight balsa used in small boat construction, and in 1954 he constructed a small sailing dinghy filled with the foam, with a design similar to the Sunfish. He showed the finished product to his friend, naval architect C. Raymond Hunt. Hunt recognized potential in the process, however he did not feel the design was particularly suited to sailboats. Instead, he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercavitation Propeller
{{no footnotes, date=November 2016 The supercavitating propeller is a variant of a propeller for propulsion in water, where supercavitation is actively employed to gain increased speed by reducing friction. They are being used for military purposes and for high performance racing boats as well as model racing boats. This article distinguishes a supercavitating propeller from a subcavitating propeller running under supercavitating conditions. In general, subcavitating propellers become less efficient when they are running under supercavitating conditions. The supercavitating propeller operates submerged with the entire diameter of the blade below the water line. Its blades are wedge-shaped to force cavitation at the leading edge and to avoid water skin friction along the whole forward face. As the cavity collapses well behind the blade, the supercavitating propeller avoids the spalling damage due to cavitation that is a problem with conventional propellers. An alternative to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Offshore Powerboat Racing
Offshore powerboat racing is a type of racing by ocean-going powerboats, typically point-to-point racing. In most of the world, offshore powerboat racing is led by the Union Internationale Motonautique (UIM) regulated Class 1 and Powerboat P1. In the US, offshore powerboat racing is led by the APBA/UIM and consists of races hosted by Powerboat P1 USA. The sport is financed by a mixture of private funding and commercial sponsors. History of the sport In 1903, the Automobile Club of Great Britain and Ireland, and its offshoot, the Marine Motor Association organised a race of auto-boats. The winner was awarded the Harmsworth Trophy. Offshore powerboat racing was first recognised as a sport when, in 1904, a race took place from the south-eastern coast England to Calais, France. In the United States, the APBA (American Power Boat Association) was formed soon thereafter and the first U.S. recorded race was in 1911, in California. The sport increased in popularity over the next few ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
