Patent ID: 8221028

Claim:
A boat lift for lifting a boat above a water level at which it normally floats, the boat lift comprising: a lift frame with attachment points for movably attaching said lift frame to a boat dock and with a boat cradle for accepting the boat and permitting the boat to move relative to said lift frame to define a docking direction along which the boat propels itself during a docking operation; a first movable lift member mounted on said lift frame for movement relative to said lift frame generally parallel to the docking direction, said first lift member including a flotation device for exerting on said lift frame an upward force sufficient to lift the boat above the water level at which it normally floats; a second movable lift member mounted on said lift frame for engaging the boat during a docking operation to move said second lift member relative to said lift frame generally parallel to the docking direction; and a linkage operatively connecting said first and second movable lift members for moving said first lift member relative to said lift frame in a direction different from the direction of movement of said second lift member, wherein said movement of said second lift member by the boat during a docking operation displaces said flotation device toward a location relative to said attachment points where said upward force can lift the boat.