Re: Helium?
Helium is expensive gas and inflating SIB pontoons would do little in the way of increased performance, or fun as the thickness of the SIB material would negate any kind of lift. Also, helium tends to escape/leak through valves very easily and you'd have to constantly be adding helium . Inflating a boat with argon gas might produce some interesting minor physical effects? If you stuck your ear to the pontoons while in water you'd probably hear a lot more from the underwater world. Might also insulate the occupants a teeny tiny bit ifmore they were sitting on the tubes in their shorts during a Antarctic cruise.
