Abstract: A float which may be utilized individually or which may be joined to other such floats or used with other elements to provide flotation for a deck or dock unit. Though the particular shapes and attributes of the float may vary for the particular use, the basic float consists of a hollow, preferably rotocast, unit which combines an exterior skin with attachment accommodations having a selectable top surface and a first and second flotation concept. The first flotation is provided by the buoyancy of the hollow structure with the second achieved through a plurality of selectively shaped and positioned cavities extending upwardly from the bottom surface of the float to a location at or adjacent the upper surface of the float. With this dual flotation provision, should the exterior skin of the float be pierced, allowing water to fill the interior thereof, flotation is provided by air entrapment within the formed cavities.