US Patent 9352812 Boat lift

A boat lift has flotation tanks positioned under sides of a frame of the boat lift. Water flow is regulated so that tanks fill relatively evenly to maintain a surface of the boat lift that is generally horizontal at all times. Hingeable connection of the boat lift to a bulkhead, along with lateral stabilization, participates in maintaining a generally horizontal attitude for the boat lift. Water is expelled from the plurality of flotation tanks by pumping water from the flotation tanks, allowing the frame of the boat lift to rise. One or more catwalks along the sides of the boat lift and connected to the bulkhead are also floating, but at a level that is independent of the boat lift frame.