Abstract: A floating drive on dry dock includes a variable buoyancy beam positioned below the deck of the dock. The beam is formed of separate cells that can be filled with air from a common feeder line. Separate inlet risers allow air into each cell. As the air moves into each cell, water is displaced out an opening in the bottom of the cell. The flow of air and water is restricted or damped to assure even filling of the cells in a beam. The feeder line and risers can be back filled with water to limit air flow between cells. Multiple beams can be used to achieve the desired buoyancy.