Centerboard schooner

A centerboard is a movable fin or sliding keel made of wood or metal, pivoting in a slot in the bottom of a vessel and contained within a watertight trunk or case. It increases the vessel's area of lateral resistance to the water. It is used mostly in small sailing boats and yachts. A centerboard schooner refers to this device used on a sailing vessel with two or more masts with fore-and-aft sails.