Abstract: A sponson comprises a floatable tubular section (110) with longitudinal, attached guideways or channels (105, 115) that house drawstrings (106, 116). The sponson is secured to the gunwale (130) of a personal watercraft by positioning a first guideway or channel above the gunwale and a second guideway or channel below the gunwale then pulling the drawstrings tight and securing them with knots (107, 117) or other means. The sponson has been filled with air, a foam material, or a combination in order to provide flotation. It also acts as a bumper to prevent damage to the craft in case of a collision with another object. The sponson is positioned above the water line and so does not cause drag when the craft is in normal use. The design is usable without modification for a variety of craft. An alternative embodiment includes an extra guideway or channel (120) for attachment to a fixture (125) previously installed on a craft.

Abstract: An improved sponson and rigid inflatable boats incorporating the same. The sponson includes a non-inflatable buoyant component, such as closed-cell polyethylene, and an inflatable buoyant component, such as one or more inflatable tubes. The boat includes a rigid hull having sidewalls along which one or more of the improved sponsons extend. In some embodiments, the inflatable component is removably secured to the non-inflatable component by a restraining structure. In some embodiments, the restraining structure includes straps. In some embodiments, the restraining structure includes resilient arms that bias the inflatable component within a pocket formed in the non-inflatable component.