Friends of mine just bought a papertiger, and its got tyre tubes inside its hull. The guy who sold it to them said it helps make it more bouyant.... to me this sounds ridiculous, if anything it would make it very slightly less bouyant because the rubber from the tubes is heavyer than the air it displaces, and then if they are pumped up more than atmodpheric press. then that weighs more too. Have I missed something, or did the last sailor of this fine craft miss the boat???