Best wastewater hose to use

[KevinE]

I have to replace the hose between my head and holding tank and was wondering about any specific products anybody would recommend. The reason I am replacing it is there is head odour in the compartments that the hose runs through in the aft cabin. It's not really bad but definately noticable. So I am looking for the most impervious hose available.

Also wondering what I can treat these compartments where the pipe ran to clean them up and remove the odours. I have read about some biological cleaners that will eat these smells but they only work in damp environments - again any specific products or do I just bleach/borax the area?

Thanks in advance
Kevin

[GordMay]

Trident Sanitation Hose:
http://www.tridentmarine.com/stage/sanitation.htm

See also:

“Decommissioning Holding tank question”
Decomisioning Holding tank question
and
“Nigel Calder on Hoses”
Nigel Caulder on Hoses

[ssullivan]

A good bleach/borax scrubbing will kill any odor... just make sure the area sparkles like a new boat, and you'll be sure you removed all of the head funk.

Trident is excellent. I also have run some Shield's sanitation hose. It is still sparlking white after a year of heavy use by charter guests. No smells.

[KevinE]

Thanks Guys

[hellosailor]

Kev-
Bleach, hydrogen peroxide, ammonia...lots of old fashioned harsh kitchen chemicals are good at destroying all organic matter. Just be careful about mixing them--sometimes that can be a bit rough on human life too.<G>

[cal40john]

I went with schedule 40 PVC. Where the pipe passes through bulkheads I have wrapped foam around it. I have a short length of hose at each end so that the pipe is de-coupled from the rigidly attached to the boat pieces. The hoses are in accessable areas, and where possible angled to drain back into the tank so nothing remains in the hose. The 10" piece from the head to the PVC is the exception for drainage. Everyone that has written on the topic agrees PVC will never have an odor. There is disagreement on suitability of use on a boat though. Some say, Peggy Hall for one, that say PVC will eventually fail due to vibration. So I have followed the directions of those who say it can work. My install has only been in service for 3 years and no problems so far, well as far as the pipe is concerned.

I had all my ports in the tank installed on top. The local MSD shop sells a pickup tube that consists of an angled rubber gasket that you shove a PVC part through that has the pickup tube. The part squeezes the rubber against the hole that you drilled in the tank and seals everything. Dealer says it will never leak. It has worked perfectly except for the time I was sure that the tank was not full and even though I felt back pressure on the head's pump I kept pumping. Well the tank was indeed full and the two vent lines filled and I was pressurizing the tank faster than the vent lines could deal with it once they had liquid in them. The seal did work well enough that there couldn't have been more than a ml or two of a leak and it all just sat on top of the tank for an easy clean up.

[islandplanet]

Originally Posted by cal40john

There is disagreement on suitability of use on a boat though. Some say, Peggy Hall for one, that say PVC will eventually fail due to vibration. So I have followed the directions of those who say it can work. My install has only been in service for 3 years and no problems so far, well as far as the pipe is concerned.

I just replaced all the sanitation plumbing in a boat that was plumbed with PVC. I'd stick with hose. One problem with PVC is that it it does have a problem it's not the easiest thing to work on underway. A long piece isn't that easy to store and you need to have a hacksaw, solvent, and glue handy. The idiot that installed the PVC on the boat I was working on did it in such a way that I had to make a multitude of cuts with a hacksaw just to get each section out. Hose is much easier to work with and seldom needs attention. Some PVC systems have a lot of joints and wherever you have a joint you have the possibility of a future leak. So what if you have to replace hose periodically? If you use freshwater to flush with while dockside and throw vinegar in from time to time it will last quite a while without becoming odorous. And make sure the waste drains completely and doesn't sit in a little loop or something.

If I was running PVC I would not have any of it going through a bulkhead. That part would need to be hose. The PVC would have to be somewhat insulated from vibration with some sort of rubber standoffs.

I'm not sure what ABYC says these days but if you plumb with PVC a surveyor may take issue with it. If you insure your boat that could bite you as well as when it comes time to sell and the buyer wants a credit for the cost of all new waste plumbing.

[Pblais]

If you live in a climate that requires winterization PVC is a nightmare. I had some in the fresh water system and it becomes a real chore to winterize. A little water in a freeze and snap, pop, leak. They only break where you could never reach.

[cal40john]

The very reason that I said I had foam (1/2" thick) wrapped around the pipe where it goes through the bulkhead is to prevent loading and vibration. Also as I said in my post there is hose at each end of the pipe so as to not have a rigid system. These precautions were given by Peggy Hall, who is not an advocate, but did give instructions on how to install it. She's big on regulations, so I would assume that if ABYC said not to use it she wouldn't tell you how, she would quote the reg. I'm not willing to pay the money to get it from the horses mouth though. Does anybody have the actual ABYC section? Has a surveyor told you PVC is inappropriate?

Here is her article on myth and folklore.
http://www.boatbuilding.com/article.php/MarineSanitationFactvsFolklore

Many sources say that PVC can be used, Dashews, Kanter, our local MSD shop say they typically use PVC.

I can see the argument that you don't want to worry about leaks and that running new hose every few years is preferable. I didn't want to have to worry about the boat gradually smelling worse until I finally had to pull all the hoses out. If I have followed the precautions correctly I shouldn't have to do anything to my system except change out the short coupling hoses, which I'm much more likely to do as they are easy to get to. The whole point of PVC is to not have to deal with it for many years. If you have hose that has to be replaced every few years then it needs to be easy to get out and put in. PVC theoretically is a permanent install so easy access does not need to be on the high end of the priority list, though I've done what I can to make it accessable.

As for the repair issue, I guess if I'm on a passage and a pipe cracks in half, I'm stuck with the bucket, most anywhere else I'll head off to the hardware store.

As for winterizing, if it's that much more work to clear out the pipe than winterizing the head and holding tank I'd have put more thought into the routing or put a drain plug in a low spot. If we had a serious cold snap where I would worry about serious winterizing, I would just pull the hose off at the head. On mine there is a short vertical section near the head, the rest is downhill into the tank.

Also I made a mistake in my first post, I said schedule 40, I meant schedule 80.

If you're only comfortable with hose, fine, that's why I presented that there are pundits that give reasons for not using PVC, but I did some research on this before I put it in, admittedly I did not buy the ABYC section on heads, but I didn't read about nor did anybody say anything about ABYC, surveyors, insurers, or boat de-valuation.

John, who might be eating his words on PVC in 5 years.

[hellosailor]

John, I suspect the issue is (as with most boat issues) more subtley complex than it might appear. What some would call a problem with rigid PVC pipe, others might call a problem with hulls and fixtures flexing instead of being rigidly fixed. I'm guessing that a stout hull and careful installation would make rigid PVC perfectly acceptable.

In terms of repairs...heck, you can always apply solvent to remelt and seal the stuff, or cut a piece out and sleeve in a new one. But now there are also epoxy putties ("plumbers epoxy") that are designed to bond to ABS and PVC and other plastics, so repairing a cracked PVC waste line would just mean cleaning it off and applying the putty.

Assuming, of course, that some demented combination of PVC joints and angles could get from "here" to "there" in the typical marine installation conundrum.<G>

[Wahoo Sails]

Funny story this ... the "best" sanitation hose is allegedly not the white stuff that we're all accustomed to, but rather a black sanitation hose that looks suspiciously like wet exhaust hose. I had a customer order several hundred feet of this from me. I ordered it from our supplier "Unaflex". When it didn't show up on time, I called them to see what the problem was. Thier response was that they had to change the label printed on the hose from "101 wet exhaust hose" to "100 sanitation hose" ... and simply hadn't gotten around to it. Anybody want to guess how much more the "sanitation hose" cost than the "wet exhaust" hose ?
Bob

[DeepFrz]

John, it's interesting that the URL that you provide as backing up your use of schedule 40 rigid PVC specifically recommends against using it. They say that if any rigid PVC is used it should be schedule 80. But they do not recommend any rigid PVC for sewage systems.

We recommend against the use of hard pipe altogether, but If you must--use only schedule 80 or ABS, and "soft-couple" (use hose) all connections to installed devices to reduce stress and shock that can result not only in cracked pipe, but damaged fittings and equipment.

I just reread your last post and see that you are using sched 80. Better but still not recommended.

Deep

[islandplanet]

I saw a few surveys where the PVC was mentioned as a deficiency but that was several years ago. I attended a survey last year where the surveyor shook his head and mumbled a few things about some PVC but he didn't list it as a deficiency.

Removing the PVC from the boat probably took 5 or 10 times as long as it would have with hose.

One advantage of changing hose every five years is it forces you to examine and perhaps replace the hose clamps.

[cal40john]

Originally Posted by DeepFrz

John, it's interesting that the URL that you provide as backing up your use of schedule 40 rigid PVC specifically recommends against using it. They say that if any rigid PVC is used it should be schedule 80. But they do not recommend any rigid PVC for sewage systems.

I just reread your last post and see that you are using sched 80. Better but still not recommended.

Deep

Yes I was trying to point out that even someone who does not recommend PVC was giving directions on how to install it. One would think that someone who says I'd rather you not install PVC, would give the most paranoid set of installation instructions to give you the most likely chance of long term success.

I did not spend much time on other sources, as I thought the most critical would make the biggest point. Here are a couple of others.

Dashew, Offshore Cruising Encyclopedia

pg 801.
"PVC pipe and fittings work very well for both fresh and salt water and for toilet plumbing. The variety of fitting available allows all sorts of creativity. White plastic typically denotes schedule 40 pipe, while gray fittings are usually schedule 80 (which is much heavier)."

Look at any of the pictures in the plumbing section, there are entire walls of PVC plumbing on their boats.


Nigel Calder, Boat Owners Mechanical and Electrical Manual 2nd Ed.
pg.361
"Plastic pipe, which is available from any hardware store, is excellent for many plumbing jobs on board, and as conduit for electrical wires."

He has an entire section devoted to properly assembling PVC pipe.


Marine Sanitation Specialists, Seattle
When I bought my holding tank from them, I was told their typical installation uses PVC pipe.

Originally Posted by islandplanet

"Removing the PVC from the boat probably took 5 or 10 times as long as it would have with hose. "

I tried to address this in my last post.

Originally Posted by islandplanet

"One advantage of changing hose every five years is it forces you to examine and perhaps replace the hose clamps."

I don't have hose clamps, except where I have hose, and I will be inspecting them.

John

[drh1965]

I'm rerunning all my sanitation lines now. Both vented loops will be mounted on the bulkhead above the head. The line sections running up the bulkhead from the head will be schedule 80 and clamped to the bulkhead. These sections do not flex. The line sections running horizontally from the head to the PVC mounted vertically on the bulkhead will be "Odor Safe". I've created a U-trap from sched 80 that connects from the sched 80 coming from the vented loop to the input side of a Y-valve mounted on the v-berth side of the bulkhead. One output from the Y-valve is "Odor Safe" connected to the holding tank. The other output is connected via "Odor Safe" to the overboard discharge seacock. One holding tank pump-out pickup tube is "Odor Safe" connected to the manual pump. The other is "Odor Safe" connected to the deck pump-out.

With this setup, I'm confident that the PVC sections fill never fail. As long as all line sections that connect between areas that can flex relative to one another are not rigid, I believe all will be fine. I do believe that some sanitation hose approaches being rigid so getting "flexible hose" would be important.

I've worked with PVC pipe for decades and it is wonderful and easy stuff to use. The fittings are simple to leak-proof and are permanent. The only potential weakness I can see with my design would be if the sanitation hose begins to stiffen over time to the point of stressing the connections to the sched 80.

Good luck.