Abstract: An elongated operating cylinder has an internal piston assembly including axially spaced diametral disks. Such assembly is movable lengthwise in the internal cavity of the cylinder. A flexible force-transmitting component is connected to the piston assembly and extends axially of the cylinder through one of its ends. Introduction of fluid under pressure into the cylinder cavity tends to move the piston assembly axially so as to apply a pulling force to the flexible force-transmitting component, adapting the cylinder for use as a fluid-pressure actuator. Such fluid pressure actuator is particularly suited for use in lift apparatus where a compact, stationary frame has upright rails along which a lift carriage is movable. The lifting force preferably is provided by the flexible force-transmitting component of the actuator which can be routed by one or more pulleys. The lift apparatus can be mounted adjacent to a dock for lifting a small watercraft from the water.

Abstract: A stationary rectangular base frame is mounted underwater and supports generally upwardly extending, swingable, parallel links or arms. A lift platform or lift pads are supported at the upper end portions of the arms and, in combination with the base frame and arms, form one or more upright parallelograms. A hydraulic jack is connected extending generally diagonally of the parallelogram arrangement and has a plunger for swinging the arms to translate the lift platform or pads up to remove a watercraft from the water or down to lower the watercraft back into the water.