How Keels, Centreboards and Daggerboards Work


船的⻰⻣、稳向板和中插板是如何运作的 A boat’s keel, centreboard, or daggerboard is designed to resist the sideways force created by the sails. The rudder also plays a part. When the boat starts to move, water flows across the centreboard in much the same way as air flows across the sail. It creates a sideways force to windward that resists the opposite force on the sail. The two sideways forces cancel each other out, leaving a forward force which drives the boat. The force on the sails acts roughly at right angles to the boom. With sails in tight (when sailing close to the wind) the force acts mainly in a sideways direction. More sideways resistance is therefore required from the daggerboard. This is why most dinghies and some multihulls have a lifting centreboard or daggerboard, so that the area under the boat can be adjusted to suit the point of sailing.


船的⻰⻣、稳向板和中插板的作⽤是，抵消帆产⽣的横移⼒。舵也起到⼀定作⽤。当船开始 移动时，⽔流会像空⽓流过帆⼀样流过稳向板。从⽽产⽣⼀个向迎⻛⾯的横移⼒，抵抗船帆 所产⽣的反作⽤⼒。这两股横移⼒相互抵消，剩下推动船向前的驱动⼒。作⽤在帆上的⼒⼤ 致与帆杆成直⻆，当帆收得很紧时（迎⻛航⾏），这股⼒主要作⽤于横向。因此，就需要中 插板提供更⼤的横移阻⼒。这就是为什么⼤多数⼩帆船和有些多体船会配有可升降的稳向板 或中插板，以便根据不同的航⾏⻆度，调节船体⽔下的受⼒⾯积。


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