The pressure will not be dissipated in the line to the thru hull (ok, yes
there will be some pressure drop, but it's inconsequential), and the back
pressure will increase with the additional hose length from the macerator.
I think this is one of those scenarios where someone asks for advice but has
made up their mind as to what they what to do and no amount of logic will
dissuade them from straying from the course they have set.
Gonna be one Hell of a mess....

"Peggie Hall" wrote in message
...
bomar wrote:
Peggie-
Check your math....
Assuming true 1" and ¾" id, this is a reduction of 44% not 25%

3.14 (.5)² = .785
3.14 (.375)² = .4415
.4415 / .785 = .5625
¾" hose is 56% of 1" hose, so the ¾" hose is 44% smaller, not 25%

Thanks...math was never my strongest subject. I was only referring to
the diameter. A 44% reduction in hose volume makes things even more
interesting.

Where he put the macerator will have a lot to do with it. So how 'bout
applying a little more of your math skills.

He said the hose is 10' long. The flow through a Jabsco macerator is 12
gal/minute. If he put it close to the tank--say within a foot, will the
distance to the thru-hull permit enough dissipation in pressure to
prevent backpressure? If he put the macerator at the other end--near
the the thru-hull, it'll prob'ly be a moot point because the macerator
will take so long to prime that the impeller will prob'ly fry before it
can (Jabsco specs call for 4' max if the impeller is dry)....but
assuming that it doesn't, what's likely to happen?

I wonder why the the phrase "trying to stuff 12 lbs of $#!* into a 10 lb
bag" has suddenly started running through my head....

Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://www.seaworthy.com/html/get_ri...oat_odors.html