Sorry, I think I forgot to mention in my write up a many years ago that I put a spacer between the seat pan and the belly to prevent squeezing the tube.

But I have had the water balloon experience--when I used the tube in sub-freezing conditions and it froze. Fortunately, the blockage melted because I was running out of control. That's when I added the blowout tube--with a plug on the end. A little valve would be better but I was worried I'd get it confused with my drinking water tube. If what you're saying is true (I'll take your word for it), no big deal.

Chip Bearden
JB