"Larry" wrote

Distilled water has none of these problems. What I can't figure out,
especially on power yachts, is why all that waste engine heat going up
the stacks isn't running engine-room-mounted distillers for fresh water
to drink.

You are spot on with this comment. When I was working at Woods Hole, in the
days before reverse osmosis, they had an engineer who knew how to tweak the
waste heat vacuum distillation units to the point that they got a gallon of
fresh water for every gallon of fuel burned; that's after the fuel had
pushed the ship or made electricity.

Take a look at the power draw for a reverse osmosis unit and then figure out
how much "fresh water" you have to carry in the form of fuel.

--
Roger Long