Abstract: Wind surfing hydrofoil apparatus for enabling hydroplaning of a wind surfing board having a mast mounted centrally thereon between a front end portion and a rear end portion of the board, and comprising a front hydrofoil mounted on the board in juxtaposition to the mast for hydroplaning support of the board; and a rear hydrofoil mounted on the board rearwardly of the mast for hydroplaning support of the board and releasable mounting apparatus for clamping engagement with the board and a dagger board attached to the board between the front hydrofoil and the rear hydrofoil and extending rearwardly within the rear hydrofoil.