Going to take a LOT of power to lift a column of water 1 km high. And you cant use light materials either due to the pressure. At 1 mile, the pressure is 2,400 psi.
I’m thinking you would be better to have two lines to the ballon and a crawler system where a “pod” lifts 1 gallon crawling up to the ballon and deposits it’s gallon into a small tank and then crawls down the other line back to the ship. The line can supply the support and the power. Mulitple crawlers can keep a supply of water up at the ballon.
How do you keep the water from freezing on the way up?????..
Please don’t say “antifreeze”
At 60,000 feet, as they propose, the pressure is 26,000 psi.
That’s about half the pressure of the chamber of a 50 BMG rifle at the peak firing pressure.