This has been very informative for me. I think I am going to look into changing out these stem valves to the Halkey... can't be too difficult. Anyone ever done that? What kind of glue for the urethane bladder?

I do use a pump (however jerry-rigged) to inflate the tube... my lungs just aren't that good. It is OK to top things off on the shore after a leak but that is about it...

Thanks for the education.