This couple is doing it :)
Look at 7min11sec
https://www.youtube.com/watch?v=Xay9BPkBcCU
regards,
Floris
I'm not sure I'd call that a tub... More like a poorly designed shower... I wouldn't trade my much cheaper portable shower that can be used inside or outside for theirs.
I accomplish having a marvelous outdoor bath/soaking/hot/cold tub if I have access to water in a campground or while boondocking by filling up my small inflatable boat. Very versatile, a boat, a tub, or even a durable air mattress, for under $30 and that folds up small and lightweight when not in use.
There's nothing quite like a moonlight hot tub in the middle of winter in the frozen north, or a cold tub in the middle of summer in the desert. If you only have a small trickle of water at your campsite, a tub can really improve your stay.