Patent ID: 7413378

Claim:
An assembly for lifting a boat comprising a cradle for carrying a boat; a plurality of spaced vertically disposed pilings on each side of said cradle each said piling having a lower portion mounted into a floor of a body of water and an upper portion extending thereabove; a pair of elongate support housings affixed to and along respective said upper portion of said plurality of said pilings on each side of said cradle; a pair of independently controlled hydraulic lifting means respectively housed in and mounted on said support housing and connected to said cradle for moving said cradle vertically; each said hydraulic lifting means including a horizontally extensible piston carrying a piston pulley block at its forward end, a stationary hydraulic cylinder mounted to said housing, and cable means having one end portion located in said housing and threaded around pulleys in said piston pulley block and another end portion connected to said cradle, transition pulley means spacedly supported by said housing and carrying a portion of said cable means to direct said another end portion of said cable means attached to said cradle vertically for moving said cradle when said piston pulley block is moved horizontally by said piston; hydraulic control means for operating each said hydraulic cylinder, and said hydraulic control means including automatic leveling system for maintaining said cradle level from port to starboard when said cradle is moved vertically by said pair of hydraulic lifting means.