> used. But still, it would probably be cheaper for a nuclear powered
> surface ship to store fresh water obtained from on-shore sources than it
> would be to make fresh water from seawater.
> Ron Kean
I beleive that all surface ships of any size make fresh from sea water even given that the cost of energy can be quite high. Even my boat can make a couple thousand gallons a day with its reverse osmosis system.
This is done because even though shore water would be nearly free, the space to store it would be incredibly expensive. A 100 footer works out to about 15,000 dollars a liner foot, and/or about 35 dollars per cubic foot to purchase so every cubic foot is valued much to highly to make it a large water tank. Then the energy required to move 10 or 15 tones of water along with the craft would add up quickly as a continuing cost factor.
Just my 2 cents worth.