is similar but slides vertically rather than pivoting. Function A centerboard is used to provide lift to counter the lateral force from the sails. This is required for sailboats to move in directions other than downwind, since the force of the sail is never closer than 45 degrees to the apparent wind. Since most sailboats are symmetric along their axis of motion, the lateral force can come from either side, which means that centerboards must use symmetric foil shapes so that'll operate with equ… (More on Centerboard)