After a couple of weeks (up to 6 sometimes) in the dinghy store I put a couple of breaths (I can't be bothered to get the pump out of the boot) in each tube to stiffen it up for rowing. I suspect it weeps around the valves, but WTF?
The inflatable seat however, is an absolute bummer & has to be reinflated every day - definitely an air valve weep, as I water tested it for leaks I was so fed up with it. I have been known to prefer a 10 gallon plastic container (spare fuel or water containers) from time to time.
-------------------- Boaty junk clogging up your shed or lockers? Chuck it in Marinaskip