Abstract: A flotation assembly made up of a load bearing structure which can be an off-shore platform, and also a flotation section comprising a plurality of flotation tubes. Each of the flotation tubes comprises a surrounding side wall defining a vertically aligned elongate pressure chamber and having an upper end closure portion that has a downwardly facing surface exposed to pressure in the chamber. The tubes are positioned at laterally spaced locations and arranged relative to the load bearing structure so as to create upwardly directed flotation forces that bear against the load bearing structure. A source of pressurized gas is transmitted to the flotation tubes to a level where the gas pressure within each tube creates a force against the side walls to alleviate compressive force of the surrounding water pressing inwardly against the side walls of the flotation tubes.