Pipe and Gasket for Waste System

[NautiBits]

While tracing some odors for the Admiral, I got a close look at the piping for the head to tank and out system. There are some fairly tight turns as it meanders from the holding tank compartment, behind the head lavatory, and under the floor to the head. It is the original 'Wet exhaust' pipe.

Has anybody done this project? Besides a 'tube of caulk, or three', has anyone tried some other method to seal the holes? Like the hole from the holding tank compartment to the space behind the shower. That should be a fairly robust seal to keep water and 'stuff' from entering the hull from that compartment. There is a drain hole in that compartment, but somehow everything does not escape through that little hole.

Ideas and proven solutions are welcome! Semi-thought through ideas are also interesting.

Thanks.

[SecondWind]

Try the product Odorlos. We have had zero "potty" smells since we started using it 12 years ago.

[amytom]

Also, what is your flushing water source? Our problem turned out to be the brackish water we're flushing with.

[NautiBits]

I'm fairly certain the odor of the moment was caused by a combination of a full tank and the vent fitting on the tank flange leaking. The tank fills up and the tube of caulk smeared on the plastic elbow does little (nothing) to keep the effluent from overflowing into the compartment. I saw no visible liquid seeping down into the hull. The odors permeated though.

In about two weeks, I will take a shot at sealing that vent fitting. I was wondering what I should expect. Is it a pipe thread that needs Teflon tape or some kind of gasket? Is it a glued fitting?

[NautiBits]

The water source is Corpus Christi Bay. There are normal(looking) sealife all around, including dolphins. I don't think it is the water source. I'm ninety-nine per cent certain it is the overflow at the broken/loose vent fitting.

So, the near-term fix is pumping out before the effluent gets to the top of the tank. (Okay, that is probably part of the long-term solution too! One of my other threads is exploring the installation of a tank monitor )

I would like to secure that leaking fitting soon though. Preferably before I install the water heater.

[Loki]

A few years ago I rebuilt my head (installed a Raritan electric). I discovered that the old hose had been routed forward towards the desk, then aft to the holding tank, for a total of about 20 feet of hose below the level of the tank. This means about two gallows of water was needed to flush the waste from the hose. Any less would leave waste sitting in the hose. My solution was to run a 1" hose vertical from the head inside the liner by the shower door above the level of the holding tank. It then goes into a 1.5" hose that runs aft, inclined downward through the shower and engine compartment to the head. In the shower its enclosed in a PVC pipe that serves as a towel bar/handhold. The result is about a pint is needed to push the waste to the point where it flows downhill to the holding tank.

[thinwater]

The thought that it is sea life causing the smell on the intake side is only partially accurate. You could filter everything visible from the water and it would still happen.

In the absence of oxygen even trace bacteria in the seawater revert to using sulfate (an ion common in seawater) as an oxygen source, converting it to hydrogen sulfide. These are facultative bacteria (not anaerobic) and they will cause this no matter how clean the water seems; the sulfate level, like the chloride level, is nearly constant in all seawater. It is not sea life rotting, it is the seawater itself.

So, yes, freshwater flush always helps.

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Also, NEVER let the tank get full. If the vent fills, clogs with TP, and you pump more in, the tank can explode. Yup, it's happened and is tough to clean up. Try VERY hard to avoid a full tank. Even waste splashing into the hose can cause plugs over time.

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If the hoses are original there is a very good chance the smell is coming right through the rubber. The smartest solution is to replace ALL of the hose~ 7 years with Trident 101/102, checking all of the fittings at the same time. This is just routine maintenance, like replacing the belts on an engine.

[NautiBits]

Excellent suggestions!

Still looking for the type of connection for the vent line fitting into the holding tank flange. Is it threaded or glued? Mine is loose and leaking when full.(I got the clear warning about avoiding this situation.) I would calibrate holding tank sensors to be 'full' at some point less than the actual top of the tank to try to avoid contamination of the vent outlet with solids. Educated guesses regarding the proper standoff welcome.

I'm thinking a clear holding tank vent hose should be the ticket. I'll probably use the same stuff on the deck drains that run from the hatch recesses to the above waterline clamshells.

Also looking at SCAD and TankEdge iSeries for tank monitors. For the iSeries there is an option for an in-tank probe versus the outside aluminum tape option. I'm not sure where the edge of the holding tank is. Is it adjacent to the starboard rudder compartment or behind the shower wall?

Does the Trident 101/102 make turns well? Does it require moderate heat gun treatment? Any lube needed for joints?

Thanks all!

[thinwater]

I did a 3-year study for Practical Sailor Mag using real waste in 7 small holding tanks. I've also tested a bunch of things on my PDQ.

http://sail-delmarva.blogspot.com/2011/ ... utton.html

a. Don't use clear vinyl for anything sanitary. It will kink over time if there are turns and it will permeate with odor within 2-3 years even on a vent. Use either we exhaust hose or white sanitary hose (the ONLY acceptable products available in 5/8-3/4").

b. Trident is pretty stiff stuff, though durable as hell. If you need flex, Raritan Saniflex is very good and quite durable; just don't force it too hard as any hose can kink.

c. A heat gun (very hot water is much better and less likely to damage the hose) is ONLY used with white PVC hose. It won't help with rubber hoses. However, if you are working in cold weather, warming the hoses and work area will help.

d. Glycerine is the preferred lube (K-Y is good too). It will not damage the hose (petroleum products can) and it will eventually dry. Never use sealants on hose; if they are needed the fit is wrong. Two clamps, opposed. Both the Raitan and Trident hoses slide over the fittings quite easily, though lube and rubber-faced gloves make it even easier, and easy is good.

e. Flush everything multiple times before you start and remember, it's only poop. We all raised kids. Honestly, it doesn't have to be messy if you think it through.

Cheers!

[NautiBits]

Ahhhh....

Thanks for not leaving me with my clear vinyl choice for vent line.

Other points well made:

Heat gun is not needed! Use Hot water if needed! South Texas may not require either.

Lube is probably not needed. Take your time, do it right. Wear rubber gloves to improve grip.

Keeping the work area clean makes it easier to keep it clean. That is how I roll.

Many thanks kind sir!

Any guidance on the vent fitting attachment?

[James Power]

Hey Nautibits,

If memory serves, the holding tank fittings were threaded into the tank plate at the factory. Might want to replace the leaking vent elbow with a new one, and sealant on the threads will help avoid leakage. As Thinwater says, avoid over filling the tank. Wema makes a good line of tank monitors. They are good quality, come with a guage read out for accurate reading, and are made in the USA.

James

[NautiBits]

Thanks JP. Always valuable 'inside'information'

Adding Wema to possible tank guage upgrade. (No Canadian source )

Will plan for early morning start to help ensure correct fittings can be found before decent parts source closes.

What does that holding tank look like below the compartment floor: wall to wall?; something less?

[thinwater]

I hope I didn't seem negative. I just saw a lot of ugly working on the article (working on my boat and crawling through many boats with problems, trying to better understand common problems). Yeah, clear tubing would be nice. A section of clear PVC pipe would work, but how long it would stay clear is questionable, as clear PVC tubing yellows in this service within ~ 5 years.

As JP says, there are good gauges. In my case (Page 83 suggested this to me) I can feel the thermocline on the tank pretty readily, and on the PDQ 32 the tank is accessible. But I would like a gauge and will add one at some point.

[NautiBits]

I didn't take anything you offered as a negative. Au contraire!

I am familiar with your pedigree and value your counsel!

To get around the ability to see contamination in the vent line, I could put an occasional 'snaking' on the maintenance intervals.

If I understand your inference re: thermocline, I don't think the tank walls are readily accessible as it is completely encased, except for the top, which still wouldn't work for me.

I don't know whether to take from the gauges comment that JP's suggestion is best, compared to the Scad and iSystem units.

Thanks all!

[thinwater]

Actually, many folks shoot the hose down the vent to clear it. Hard to reach on the 32 (between the hulls).