Every cruiser and pro I know who has gone to PVC would never go back to hose. Boatpoker on this forum recommends it over sanitation hose. Nigel Calder recommends it over sanitation hose, as does Steve D'Antonio, and Morgan's Cloud - for just a few. Don't know who your pros are, but these four are pretty knowledgable.
Add me to the list.
We replaced our hoses with PVC. They survived our wreck (3-5000
impacts over 3 days of storm). No head smell in 12 years. Highly
The forward head, which I'd originally thought would be impossible,
turned out to be feasible with lots of joints, and some creative
vocabulary. The aft, which I originally thought would be a piece of
cake, I then thought couldn't be done at all, actually turned out
However, I learned a bit along the way. As nobody's going to be
grading you on neatness, slop the crap (pardon the expression) out of
the joints with cleaner, and then with the glue, when you're making
the assembly (do it all dry first, of course, and allow for the full
depth of insertion as the glue will act as a lubricant, letting you
seat it fully where it won't go, dry).
I didn't do that in my forward head installation. As a result, I had
two very minor seeps at two joints after the incident (more below).
Those were cured with careful sanding and addition of, first, more
glue preceded by an acetone wipe (to clean and soften the plastic),
and followed by some penetrating epoxy (more flexible than laminating
or general-purpose epoxy) with a thickener added to keep it in place.
As I'm currently on the hard, I shut the thru-hull connection, opened
the anti-siphon valve (like you'd see in a laundry connection), and
poured water into the system until it was full (both toilet and hull
ends of the line), and waited a week. No seeps. The aft didn't leak
So, from that, I get...
First, if you think you're being ridiculous in your application of
cleaner and glue, and follow up each joint with swabs around the
perimeter for good measure, it's unlikely you'll ever have a leak.
Second, if there *is* a very small leak, it can be addressed, if you
can get to it. I'd originally thought I'd have to cut out the
offending joint - but even that's possible to do.
Meanwhile, as an establishment of the bona fides of this process, this
hard pipe stood up to huge hull flexing and pounding (impacts) - more
than you'll ever encounter in normal seagoing life. I estimate, based
on time and wave interval, that our hull took not less than 3000 and
probably more than 5000 huge crashes on rock. The flexing our hull
provided in her defense is totally awesome, and for which we're
without words to adequately express how grateful we are that was so.
From that I can provide my own assurances that, done right (joints
fully glued) and supported (no flailing around) that it's unlikely
you'll ever have to deal with that again.
Given the stench of the hose we took out (the good stuff), I'm very
happy to not have to face that thought in this boat's lifetime.
And, finally (you knew I'd get here, eventually, right??), for those
so inclined, my galleries have the gory details on the installations
of both heads' hard pipe, and I can give you the links if you like.
However, in general, I think the forward head (the more complex of the
two) was Feb06 in the refit gallery.
My apologies for these early galleries. There were a dozen major
projects going on at any time, and I had not yet started isolating
projects in separate galleries. As such, there are many intervening
pictures of other stuff going on which you'll have to slog through to
get them all..
Now Ė as to the pix themselves:
Pictures: Flying Pig Early Refit + Projects/Early_Major_Alterations_Work/04-05
Pictures start in this album; they are of the forward head, which is
actually a much more complicated installation than the aft. They
continue into the next gallery, which is
Pictures: Flying Pig Early Refit + Projects/Early_Major_Alterations_Work/04-26&27-05
where you can see the installed product.
This is another start point link:
Forward PVC start
Pictures: Flying Pig Early Refit + Projects/Finishing_Touches-Readying_To_Splash/5-06-Early
Keep the pipes clean, as well as free of scale. Flush aggressively -
all the while anything's going in the toilet, and then a calculated
full-length rinse (enough water in pump strokes to replace the volume
in the pipes), followed by a similar volume of air. We use 20
strokes each after the continuous flushing under way... The
aggressive rinsing makes sure no urine remains in sea water, which is
what clogs the pipes/hoses with scale. The dry pumps go until the
through hull burps...
If your anti-siphon valve is in working order, what you get is a very
small amount of water at the duckbill/joker valve (the water doesn't
entirely go out with a dry pump), and the rest of the entirety bone
dry. What you have will be, essentially, a dry stack.
The few times we've had to get into our system, even the exit
end is not only clean and scale free, but dry, as proven when we
closed the through hull valve in order to disassemble it. For an
example of that, see this pic, 5 years after installation - it's the
end of the forward head PVC at the Y valve:
Pictures: Flying Pig 2013-2014 Shakedown/Y-Valve and Hose
If there's nothing in it, your pipes can't possibly smell. Use a
rubber sleeve/coupler designed for repairs to drain lines to seal the
joints between toilet/pipe and pipe/Y-or-exit. I made a very careful
butt fit so that the pipe was tight against the hose fitting; a small
section of hose brings the outside diameter to the same as the PVC.
Couplings then slide over both sections, with hose clamps at the ends.
I added another hose clamp at the butt joint; if that somehow wasn't
secure, the ends would prevent against leakage, but in my experience,
there is none, anyway. Getting into it is merely a matter of loosening
the clamps, twisting the coupling to release any pressure-induced
sticky, and slide it up the PVC. Reverse install/replace.
You can see an example of that when I replaced my overboard Y-valve
(holding tank or straight through):
Pictures: Flying Pig 2013-2014 Shakedown/Y-Valve and Hose
So, if you have the time and the inclination, you can replace your
sanitary hose with PVC, and be done with smelly pipe forever. If you
prefer to keep hose, to keep it fresh and scale free, follow the
procedure above about pumping. FWIW, I credit Peggie Hall, the
Princess of Poop, with that concept, LOOOOONG ago, on an NNTP
newsgroup, rec.boats.cruising. You can still find her on the
internet, but she's no longer on newsgroups. She has also written
several books on marine sanitation and controlling boat odors. Highly
I expect to pass this way but once; any good therefore that I can do,
or any kindness that I can show to any fellow creature, let me do it
Let me not defer or neglect it, for I shall not pass this way again.
- Etienne Griellet