Abstract: A light guide is disclosed and includes a flexible elongated tube having an inner surface and first and second ends. A non-supercritically dried hydrophobic aerogel film is affixed to the inner surface of the tube as a cladding layer, and a fluid core is disposed within the tube. The fluid core has a refractive index greater than the refractive index of the aerogel cladding film.

Abstract: A universal foot fin is disclosed for use with float tubes and pontoon boats which can be selectively adapted to propel either forward or backward in the water, while simultaneously allowing the user to walk forward in either adaptation without removing the fin assembly. The fin assembly is described as being either (in simplest form) a separate FIN member to be attached to mounting fixtures which can be permanently affixed to or molded integral on wading boots, or as a complete assembly including a base member to be secured to wading boots by an releasable binding mechanism In use the fin member pivotally retracts in an upward position for walking.