Abstract: Boat jacks operable in pairs to lift a boat off a wheeled carrier, each jack resting on a "T"-shaped base and supported by a tripod, each jack being specially modified by providing a horizontal lifting member on the front of the jack component that is movable up or down by a cranking arm, each horizontal lifting member being lodgable in longitudinally extending side channels provided on the hull of a boat, each base being clear of the boat, and a connecting chain provided between the horizontal lifting members to furnish additional lifting support to the jacks and to prevent their lateral movement one away from the other.