Sail area is usually planned by boat designers based on the boat's size, displacement (weight), and hull shape and configuration - not the number of masts or sails.
帆面积通常是由帆船设计者根据帆船的尺寸，重量，船底形状和配置来确定的，而非根据桅杆或船帆的数量。
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The centerboard can be raised to decrease displacement to allow the boat into shallower water - and it should swing up and back if it hits the bottom when sailing with it down.