I have just put in a patent for a new ultralight fishing pole that is filled with helium. it is basically theory work and no prototype has been developed, although firms like Maver, Daiwa and Garbolino have shown interest. Can anybody work out the following: if you have a 13m pole, and you take off the top kit say 2m, leaving you 11m, the pole now weighs 600 grams with air inside, the butt end has a inside diameter of 70mm and the smallest end has a inside diameter of 10mm. How heavy would the pole weigh if it was filled with helium. Do not ask me for the answer as I do not know it yet.