An apparatus for increasing the buoyancy of a wheeled vehicle includes a ski to be disposed under at least one tire or wheel of a wheeled vehicle; a boot having a bottom wall secured directly or indirectly to the ski and side walls substantially perpendicular to the bottom wall, wherein the side walls of the boot are configured to laterally constrain the tire or wheel of the wheeled vehicle; and a tire block pin for connecting the side walls of the boot to one another to increase rigidity of the apparatus and to rotationally constrain the tire or wheel of the wheeled vehicle and/or tie downs for securing the wheel to the ski. Methods of using the apparatus are also disclosed.