Sewage Hose or PVC Pipe ?

[skipgundlach]

Hi, y'all,

Amen to the timing marks and dry fitting beforehand. Be aware that the pipe will go further into the joint once it's lubed up with cleaner and goop than you can get it in dry, however, making final depth/length issues of some note. My solution was to lightly sand in order to allow it to bottom, which also gave more tooth to the adhesive (which is lots solvent, too).

Second that I did differently, based on the pix, was to be sloppily liberal with my glue. Nobody's marking for neatness, and I for sure didn't want a joint seep. More on that later...

Third, I made very tight butt joints at the toilet and thruhull ends. A short section of sanitary hose acted as a collar to build up the nipple to exactly the diameter (outside) of the PVC. That allowed a butt joint (tight, based on very careful cutting) between the nippled end - see depth issues above - and the raw PVC. I then used a rubber sleeve joint (as you'd use in underground sanitary pipe) over those points, but added a third clamp at the joint. Thus, any tiny seepage which might possibly pass through that butt joint would be prevented from moving down the outside of the pipe. More on that, too, later.

So, if you wanted to see my pix, you'd have to wander through the thousands of pix in my refit early section in my gallery, but it's essentially the same as the original poster's in execution, the only differences being in the details of my particular installations. However, I even did a blind section in the forward head, which ran under the toilet base from the sink cabinet, starting with a fixed (already glued) ell on the end of the appropriate length, making my timing mark for the incoming ell on the end under sink cabinet. The end run wasn't angle critical (other than the under-sink ell, and I put in the exhaust pipe dry-fit before making that particular mark) so I didn't need such a mark coming out of the fixed ell.

I proved the utility of the sleeve when I had to service my Y valve. If you lube the inside of the sleeve, and the outside of the pipe, with KY equivalent, it will slide right back up the pipe, easily. Proof of concept was that, after more than 2 years, there was no staining, let alone smell, at the joint, which was easily exposed just by loosening the clamps and sliding the sleeve/collar out of the way.

Another trick, learned from Peggie Hall, the Head Mistress, when she was active on the rec.boats.cruising newsgroup, related to the potential for scale buildup, again proved in execution above with NO accumulation during that removal, is that we pump aggressively to rinse after each use of the head, and then again aggressively with air to force out all the water we've used to rinse with. The antisiphon valve prevents water intrusion, as the tube is now under pressure (to the extent that the pipe is below the waterline, of course).

However, every so often, we also descale - that is, we use either vinegar (not nearly as effective, but done regularly, will do just fine) or muriatic acid. A cup into the bowl, then pump so it enters the exit stream. Listen for the bubbles to stop, and give it another pump. Rinse (metaphorically, of course), repeat, one stroke at a time, until it's all through the system. Then give it a vigorous rinse.

For us, with our PHIIs, our metric for keeping the pipes empty and free of scale is 25 pumps of water and then the same of air, each use. My calculation has it that the pump 25-stroke volume is more than sufficient to put everything which is in the standing tube into the falling tube by double or more. The much-faster (to prevent as much as possible any water falling past the bubble you're moving through the system) pumping at the end is concluded when you hear a constant stream of bubbles out the bottom.

FWIW, I used an ell with a vertical (on the side) screw female joint and a washing-machine type of antisiphon, on the downhill side. In the unlikely event of the need to rod the line, I can easily remove that to get a 1.5" hole, above the water line, to start from.

Finally, to the survivability of this installation, while I did support the tubes as appropriate, I didn't tie them tightly to the hull which, being fiberglass, will flex. That will allow you to avoid "hard points" in the system. Long-time followers of our adventures will recall that we had a severe wreck early on.

We were on a flat rock, with 8-10' seas picking up and slamming our boat back down, at a 60* from vertical angle. Based on the length of the storm, we estimate 3-5000 impacts. YMMV, but I doubt that you'll encounter more severe conditions in actual use - and, yet, the system survived just fine.

Moreover, as to using a short section of even the best hose as a joint, eventually, that will, also, inevitably, smell. We have NO head smell. And, amen to just closing the thru-hull seacock for the solution to a failure. Belt and suspenders, each of our THs has a wooden plug secured by a line next to it, in the event of a failure of the seacock-to-TH joint, however.

And (doing a Columbo, here), SeaLand even recommends using PVC, selling adapters (much more expensive than our solution, of course, as they're specialty items) for PVC-to-hose, due to the expense of hose. And theirs don't allow for disassembly such as we have, but, of course, since they connect to hose, that's not a big deal.

And, of course, I agree with the comment about builders' not using this stuff because it's so much easier to just pull a hose. Island Packets seem to have some mental block about runs, because there are some which are well over 10 feet. Thus I can understand the need for them to pull hoses and whack them on the dock from time to time, as that long a basically flat run, even doing what we do for prevention, would be nearly impossible to manage. PVC in that application probably wouldn't be such a good idea. Of course, making a new hole in the boat and avoiding such idiocy would be a better one (idea), IMHO :{))

Anyway, cudos for a great looking and clean installation. Hats off to you!

L8R

Skip, currently lying George Town, Exuma Bahamas

[SV Demeter]

Originally Posted by GordMay

I wouldn’t expect a S/S wire saw to “rust into nothing”.
The BCB Commando Wire Saw consists of a 28" length of 8 strand braided stainless steel wire with a ring or strap attached to each end.

$5.95 ➥ BCB Commando Wire Saw

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Gordo you frighten me with your ability to pull up this sort of stuff...

[GordMay]

Originally Posted by SV Escape Plan

Gordo you frighten me with your ability to pull up this sort of stuff...

Then, be afraid. Very afraid, for I'm not near done.

[foggysail]

Originally Posted by bstreep

FWIW, I just see too many problems with "stuff" sliding around and putting strain on PVC to use it. As well, we had a charter boat from the Moorings almost sink on us because a PVC fitting was used on a water intake for the fridge, and it broke as it was in the bottom of a lazarette.

Maybe a PVC fitting did fail and then again, maybe it was plastic/nylon and not PVC.

I have used 1 1/4" & 1 1/2" PVC waste lines for extensions on pipe wrenches when I needed extra torque .......like four feet of the stuff over a wrench handle. I have hammered on PVC, schedule 40. I can attest to its strength. It is not easily broken even in 20 degree F weather. It is always flexible but not as much as hoses are. AND THEY DON'T STINK!

If you feel PVC is not an option for your boat, that is fine, nothing wrong with that at all. But do not underestimate PVC's strength.

1 1/2" PVC is rated for almost 200psi, has a required minimum burst pressure of 1060psi. PVC is very strong, inexpensive, easy to use, commonly available pipe.

PVC needs to be derated by 20% when operated at temperatures of -140 degrees F. Brittle? I think not.

Foggy

[IdoraKeeper]

I use short lengths of hose as shock isolation. In the installation on Idora, the hose is all dry unless pumping out one way or another. Keeping the lines empty and dry does mean closing a valve to keep stink from coming back up the line. Treating the tank does help considerably. I do not use PVC on the rinsewater input side. A failure on the input side is a leak below the water line. The input line does not stink, so no big deal. It's an experiment that is working sofar.

Todd

[NoTies]

The main problem with PVC on salt water toilet systems is the inability to remove it and beat the hell out of it on the jetty when you have forgotten to acid flush the calcium build up inside (as I discovered this year)

[Wand]

Originally Posted by Cotemar

This thread was started to address “Boat Smell”, by using a permanent PVC pipe solution. A lot of cruisers just deal with having a progressively smelly boat then changing the sewage hose when it becomes almost unbearable to take the bad “The common theme with this “Boat Smell” problem from reading other post is that it should have been replaced a few years ago or I can not sell by boat Over time most boat owners have no idea that their “Boat Smells”, because they are on it all the time or the miss’s has sprayed or has candles burning. Of coarse your friends or guest will not tell you, but you had better know they talk about it together or to others.It takes years, but over time all “Boats Smell” because of poor grade sewage hose.Most of you can remember boat shopping and getting on a few boats with this “Boat Smell” problem. Those boats stay on the market for a The only reason one would go with PVC piping verses sewage hose is to address the “boat smell problem” over a long time.

If you've really found the solution to the sewer boat smell, you're surely in line for the nobel prize for saving marriages or some such...

[Cotemar]

NoTies,

You should never have to beat anything on dock. Unless you really want to.

Urine interacts with salt water to make calcium deposits.
Most cruisers are using "Fresh Water Flush" which eliminates the calcium deposits.

Cruisers leave the toilet seawater inlet valve closed. When flushing the toilet, they just leave a cup next to the sink and fill it with water from the sink and pour it in the toilet and pump the valve.

#1 Use one cup of water then pump valve
#2 Use three cups of water in the bowl before you start. When finished, then pump like crazy.

Mark

[NoTies]

Most cruisers I know are using salt water for flush and yes, I know about the uric acid effect (I work in water treatment) but somehow my lecturing of other people somehow missed absorption into my own brain and it got left off my "must do" list. Didn't even have a jetty to do it at so the dinghy got beaten on instead.

[Privleoplag]

just a note, you can cut pvc pipe easily with a small diameter string.. like masons string or even something as convenient as 1/8 inch or even 1/4" braided nylon or poly, although the 1/4" is getting a bit thick for cutting, the smaller diameter string works better.

[Nik]

I have bent PVC with the exhaust from my propane grill. Have to keep turning it, not to close and wear gloves. but it does work.

[colemj]

Originally Posted by NoTies

The main problem with PVC on salt water toilet systems is the inability to remove it and beat the hell out of it on the jetty when you have forgotten to acid flush the calcium build up inside (as I discovered this year)

This is true, but the advantage of PVC is that you can just cut that section out and replace it for a couple of bucks.

Mark

[bstreep]

Originally Posted by SailFastTri

That "PVC" intake fitting was more likely a nylon fitting, not PVC,

Oh, no. It WAS PVC. "Just like Home Depot". The boat had been moved from another base, and the BVI base was REALLY ticked that someone had done this. Not only that... Ready for this? It was an elbow that had broken before, and someone had glued the 2 pieces back together... BELOW the waterline.

[troppo]

Originally Posted by bstreep

... Ready for this? It was an elbow that had broken before, and someone had glued the 2 pieces back together... BELOW the waterline.

That should be okay if they used waterproof glue. . . . . Ah, maybe not . The mind boggles at what some people do for repairs.

[wingless]

Originally Posted by skipgundlach

Amen to the timing marks and dry fitting beforehand. Be aware that the pipe will go further into the joint once it's lubed up with cleaner and goop than you can get it in dry, however, making final depth/length issues of some note. My solution was to lightly sand in order to allow it to bottom, which also gave more tooth to the adhesive (which is lots solvent, too).

The OP write-up is very good.

The only improvement would be to include using / listing usage of a solvent cleaner during the joining process.

The pipe and fittings have an exterior skin that is softened by the cleaner, permitting the best bond w/ the glue.

The other thing I do when using these pipes and fittings is to put a small 45° bevel using a file around 360° of the pipe exterior end, before jamming it into the fitting, to have the pipe shape match the fitting shape.