US Patent 10029761 Boat expanding and contracting apparatus

An expandable and contractible boat comprises a first outer hull and a second outer hull symmetrically shaped and arranged with respect to one another. The first and second outer hulls are movable relative to one another, and each of the first and second outer hulls includes an outboard side portion, an inboard side portion, a bottom portion between the outboard side portion and the inboard side portion, and a concave chine portion connecting the outboard side portion and the bottom portion. A cross-section of each of the first and second outer hulls is recessed at the concave chine portion.