Abstract: A hollow, elongated tubular member, constructed of flexible resilient material, an inlet-outlet for admitting and discharging air, and including a separate, removable sleeve constructed of material as resilient, or less resilient than the buoy bladder, for its upper portion is adapted for deployment as a portable, large, and versatile marker buoy. The height above the waterline is adjustable by controlling the amount of air therein, the sleeve is removable, interchangable, and is to be printed with the insignia to designate its use. The air pressure in the buoy is used to hold the sleeve and any lightweight device inserted between the two members in position without the use of a fastening device. The method of deploying this marker buoy includes the steps of partial inflation, positioning of the sleeve, attaching ballast weight and or anchor weight, and adjusting to the desired height above the waterline by controlling the volume of air therein.