...My understanding is that Larry simply prefers distilled water, ...

Oh, if that's all then I think it is a great idea. I thought his
argument was that distilling using engine heat was more efficient and
was responding to his post of Sept 8 where he said:

"And any RO uses more power which equals more fuel expense we can no
longer afford. It's a shame to let so much heat just blow out the
stacks
and be poured overboard as hot seawater when there are so many uses
for
it....like distillation, heat engines driving gensets, etc. "

This confused me because RO uses much LESS energy than steam
distillation. So, basically the question I've been asking all along
is: If the heat is available to do work then why not use it to make
RO water which will give you a lot more water for your work than
steam? I gather from you that the answer is "because I want steam
distilled water and I don't get any of that from RO." I'm good with
that. It was the "more power" thing that threw me.

... Though I am not well versed in this, and have not tested the waters.
distilled and RO are different, aren't they?

Yes, Larry is right, there may be qualitative differences between
typical RO water and steam distilled water. His preferences in this
seem defensible to me as long as we're talking about drinking water
and not washing or cooking water. RO desalinated water is probably
better than the water that comes out of your taps at home if you don't
filter it. It is good enough for drinking -- I'm a lot happier
drinking it than the water that gets used in most of the developing
world -- but for some things steam distilled could be better yet.
Steam distilled water is a luxury version of drinking water.

He never said distilling was more energy efficient than RO, but was
looking to capture engine waste heat to make distilling more efficient
than it is using conventional methods.

I thought he did say distilling was more energy efficient which is why
I was confused.

And if it could be done, it would be of benefit to sailboats too,
since they are often under power, and their engines waste many,
BTUs. ...

I think Larry said he didn't think it would be practical for sailboats
(he used all those big letters), but it would be neat if it was
workable and affordable. I'm hoping he will do the hard work for us
by rigging up a prototype on his diesel truck and then share the
results with us. It would be lovely if it worked!

Capturing wasted BTUs is the most important issue.

Now you've confused me -- bless my heart I am dumber than a box of
rocks. I was good with "I steam distill water because I want steam
distilled water", but if capturing the BTUs is the most important
issue then why use an inefficient desalination system like steam
distilling?

-- Tom.