Sewage Hose or PVC Pipe ?

[Cotemar]

Cruisers,

I wanted to share my experience replacing my sewage hose on our Catalina 380.
We purchased this boat used. It was only three years old, but the head really smelled bad. After we purchased her, most locals said that they had looked at the boat but it smelled, so moved on to look at other boats without issues. We negotiated a better price based on the head smell problem.

Now, what’s the solution?
Hose is simple to install but will have the same problem in a few years as the hose permeates with urine & sulfurous malodors over time.
Better sewage hose like Trident Premium Sanitation Hose, Shields Poly X Sanitation Hose or a SeaLand's OdorSafe Plus Sanitation Hose is very expensive and gives you a few more years, but will still odor permeate.

You could try my Hose Foil Tape Method to extend the life of your hose if schedule 40 PVC will not work for you.

http://www.cruisersforum.com/forums/...ml#post1377635

Schedule 40 PVC house hold pipe is cheap and will never odor permeate, but takes more time to install.
We went with the PVC. We sold the boat after six years. Never had any plumbing problems and the boat always smelled great. The boat sold in one week.

1) This is standard Schedule 40 PVC 1-1/2 inch house piping.

2) Cut piping with a hack saw and small wooden miter box.

3) Sand the O.D. of each pipe end, so they dry fit and seat to the bottom of the coupling it will join to.

4) Optional: put a small 45° bevel on the end of each pipe using a file or sander before jamming it into the fitting, to have the pipe shape match the beveled fitting shape.

5) Dry fit the whole system together.

6) Put black timing marks on each pipe and fitting with a black magic marker.

7) Prep each joint with solvent cleaner just before gluing.

8) Start at one end and solvent clean & glue and align your black timing marks as you put the pieces together.

9) At the toilet use a 1-1/2 coupling with a compression fitting on one side to connect to the toilet. Works great and never leaks and can be taken apart for servicing.

10) At the deck fitting I used just a short piece of hose since this will only be exposed to sewage for short periods of time.


I thought it was a good do it yourself job and will do it again on my current new boat in the near future when needed.

Mark

[capngeo]

Nice write-up!

[SailFastTri]

Very nice

[Wand]

I've used that pvc piping on boats for drains mainly and have never had any problems. Plenty of people said I shouldn't and others still smirk when I show them but I couldn't see how there could be a problem and none have surfaced. I think for stinking head pipes it's a smart solution.

A lot of boaters, mainly those new to the mystique I'd guess, go only to boatshops for their gear; and the industry naturally is keen to keep it that way. But the insanely priced head hoses are a good example of why it's smarter to look elsewhere for comparable products in general hardware etc.

Now, don't get me started on stainless steel...

[islander28capt]

Another example of a little extra effort and less cost is a better out come. Very nice job and great post! Too bad we cant get some (at least) of the marine service "pro's" to try this aproach!!!

[DeepFrz]

I noticed in one write up on a Kanter (one of the premier custom builders) that they had used PVC piping. I seem to remember that they used short lengths of hose at head and tank connection points though.

[islander28capt]

I can still see where the flexability requirements of a boat still need to be considered but with some care pvc seems like it has a place taking over for some of the hoses we all have flopping around in one area or another.

[Chief Engineer]

The reason pipe isn't used is becuse takes brains to install.

Time is money

[IdoraKeeper]

I am gratified to see someone make a post like this. I did the same job last winter and used pvc. Chief is correct it takes time to figure out all the angles and make the correct cuts. I used a miter saw with a fine blade and never had a fit problem. Care must be taken not to preload the PVC where it makes contact with vessel structure. Over time this could cause cracking.

In my view the main concern with pvc is shock load when the vessel is underway. If you have a twin diesel, fast sport fishing boat and like to run hard in large waves you might have a problem. So far I have zero defects on Idora. It was an experiment that seems to be successful.

I hope I have as much luck with engine mounts.

Todd

[Conall]

Nice looking job. The fittings you used are called DWV ( drain, waste, vent). Pressure fittings have twice the glue area, and can handle much more abuse in regard to the occasional knocking around. I'm not critiquing, just letting all know that there is a more robust fitting available that can handle quite a bit of pressure and rigors of boat life.

Conall
conallsboatbuild.blogspot.com

[MarkJ]

Great work!

[wsmurdoch]

When the electricians installed the PVC conduit in my house between the meter and the breaker box, they heated the PVC conduit to make a bastard angle compound bend that could not be made with stock fittings. They used an electically heated box to warm the conduit then bent it to the required shape. I did a quick Google search and found that there are several types of tools for heating and bending PVC pipe and conduit. It might be a useful technique in the confined, curvy, and odd shaped interior of a boat.

[GordMay]

Originally Posted by Conall

... The fittings you used are called DWV ( drain, waste, vent). Pressure fittings have twice the glue area, and can handle much more abuse in regard to the occasional knocking around ...
Conall
conallsboatbuild.blogspot.com

When selecting PVC pipe you should check the ASTM listing number.
You don’t want to use PVC pressure pipe (ASTM 1785) in place of Drain, Waste & Vent pipe (ASTM 2665); although much of the Pressure pipe, commonly sold in local hardware or homesupply centers, will meet (& be labelled accordingly) both standards, and is listed on the pipe as approved for both ASTM1785 & ASTM2665.
PVC pressure fittings generally have sharp bends on the corners, whereas DWV fittings will have a radius curve at all changes of direction, to reduce internal friction of flow and permit rodding a line.
Accordingly, PVC pressure fittings SHOULD NOT be used for drain, waste or vent applications, because the sharper bends will restrict the flow of gravity pressure waste systems which would cause clogs, and they will not permit a snake to pass through the joint for rodding the line.

[osirissail]

Rigid PVC pipe is great - but - as Chief Engineer put it nicely - "takes brains to install." You are dealing with "rigid" which means it does not bend like hose. Also it is subject to joint failure if not "very" properly installed. You just do not slap some glue on the pipe end and stuff it into the fitting.
- - From the OP's photos you can see all the alignment marks he needed to get each section in the proper location. And, using PVC pipe means building the system from one end progressively down to the other end. That means if you have a joint failure somewhere in between - you're F***ed. You have to cut out sections that may not be accessible to get cutting tool into. If you are underway in the ocean when the pipe or joint fails how are you going to stop the water flooding the boat? With hose you can shove a wooden plug or whatever into the hose while bending it as necessary for access. Can't do that with rigid PVC.
- - Others have mentioned the "shock loads" boats experience when in the ocean or seaways. Unless the PVC pipe is strapped and supported in a manner that does not allow slamming or vibration, it is subject to fatigue cracking and failure.
- - Retro-fitting a boat with PVC is not easy for all the reasons mentioned here and by others mainly due to the PVC being "rigid." In new construction where the interior of the boat is "wide open" or constructed separate from the hull - it is a lot easier to work with rigid PVC pipe. But again manufacturers have to consider down-time repairs and replacements, so flexible hose is the standard.
- - And PVC pipe will "lime up" when used with sea water and human urine just like hose. And you cannot take it out and pound it against the dock to flake out the lime.
- - You just really have to be "smart" and very selective on how and where you use rigid PVC pipe.

[Sailmonkey]

Originally Posted by osirissail

If you are underway in the ocean when the pipe or joint fails how are you going to stop the water flooding the boat? With hose you can shove a wooden plug or whatever into the hose while bending it as necessary for access. Can't do that with rigid PVC.
.

ahhhh, but you can. A wire pipe saw will cut pvc in no time, then you just stuff one of these in......