Abstract: An apparatus and method wherein a pair of frame members each having four jacks and placed one upon another are provided with other jacks which are horizontally movable to change the relative position of the frame members, and the jacks are suitably operable sequentially to provide the frame members with a capacity to be moved freely within a dock, whereby a propeller or rudder for a large ship is held between a pair of scaffolds provided on the frame members and the article is then conveyed to the desired place and mounted in the desired position of the ship.