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A canting keel is a form of sailing ballast, suspended from a rigid canting strut beneath the boat, which can be swung to windward of a boat under sail, in order to counteract the heeling force of the sail. The canting keel must be able to pivot to either port or starboard, depending on the current tack. ==Purpose and history== The traditional yacht keel performs four functions: * the development of lateral water force to resist lateral aerodynamic force from sails and superstructure, * the physical housing of ballast load as low as possible, * roll-damping to resist energy inputs from waves and disturbed water, and * a contribution to directional stability. The traditional fin keel, pointing straight down from the boat, provides no righting moment when the boat is level. The heeling force of the wind on the sails is therefore not counteracted until the boat has heeled over by a certain amount, moving the fixed keel to windward of the centerline. The purpose of the canting keel is to allow the boat to sail closer to level which generates maximum speed, by swinging the keel to windward and developing an adequate righting moment to keep the boat's angle of heel closer to level. With the canting keel handling the ballast functions, lateral resistance and steering can be managed separately with a foil (or pair of foils, either on each side or fore and aft), such as daggerboards. This allows for much quicker maneuverability than traditional keelboats, with about half the weight usually required for ballast. First patented 27-2-1981 by NSW business man Mr Arthur S Walker patent number 67911. A version of the technology was invented and patented by CBTF Technology in the 1990s. The canting keel's first use was in the Vendee Globe of 1996-7 which Pete Goss completed in a 50ft, Adrian Thompson-designed yacht named ''Aqua Quorum''. Development of the yacht and the events of the Race are described in detail in Pete's subsequent book ''Close to the Wind''. Subsequent use in major competition was in September 2004, when five boats using the canting keel in the Maxi Yacht Rolex Cup placed ahead of the previously unbeaten world champion ''Alfa Romeo''. ''Alfa Romeo II'', designed by Reichel/Pugh features a canting keel and fore-and-aft twin foils (CBTF). A variation of the canting keel is the 3d keel invented by François Lucas in 1998, which allows movement in three directions (side to side, forward and aft, and rotation). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Canting keel」の詳細全文を読む スポンサード リンク
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