continued quest for sweeter smelling head

[markxengineerin]

The 3 cabinets pictured have a tank smell inside, worse when left closed for a while, and especially bad when running the macerator pump to discharge the tank (maybe this is a clue?)

All the head hoses are contained in these cabinets, but they are only a year old, and I wrapped them with foil tape before installation to try to keep smells inside. I omitted the direct discharge hoses for simplicity, in diagram, but they exist with 3 way valve. There are plenty of hoses that sit "full", nothing I can do about it in this layout.
The vent is confirmed to be free-flowing.
The hoses are not the expensive ones, but in any case I'm having a hard time believing my issue is the hoses. I'm looking for other ideas.

Gel-coat in cabinets impregnated with smell? I have bleached it
Pin-hole leak in something that leaks gas but not liquid? I don't see any drips.
Duck-bill valve at top of vented loop stuck open? Can that cause a smell?
Maybe some odor is inevitable on an old boat?
The old Groco K toilet "recirculates" a bit, I need to bore it out and make a new piston, as the cylinder walls are all scratched up. I imagine this isn't helping, but I don't think it's the primary source of smell, as I flush enough to clear. I want to think it's something that gets much worse during overboard discharge, that's my best clue. The pump I use is Dometic TW12- diaphragm style.

[wholybee]

Is there a valve on the tank out? Most hoses will permeate (sometimes in only a few months) with stink if they are left with liquid waste in them. They need to be dry. If it is possible to reroute that to pull from the top of the tank, or if you can replace the hose with PVC pipe, or add a shutoff valve to keep that hose dry when the tank fills again.

[rbk]

What Warren said but also could be your habits. Most have a tendency to stop pumping/flushing once the bowl is evacuated, this leaves effluent in the hoses. Keep pumping after the bowl is evacuated to ensure effluent makes it to the tank and only water is left in the hoses. Leaving effluent in cheap hoses only makes it worse, faster.

[markxengineerin]

The way it is plumbed, there is somewhere between maybe 4' minimum and 8' maximum of hose that's going to be full depending on tank level and how things settle, because the "out" hoses connect to the bottom- no valves.

I wish I had known about the "pull from the top" thing when I had the lid removed from the tank- that would have been the time to convert. I assume that involves adding an internal tube? I didn't even know this was a possibility, thought all exit hoses came from the bottom.

I flush extensively as part of debugging this problem, filling my tank much quicker than I'd like, so don't think that's it.

[wrwakefield]

What a pain.

Have you consulted Peggie's book Getting Rid of Boat Odors?

It is also difinitive regarding head plumbing- including an easy way to install inlets/outlets through the top of holding [or any non-flamable liquid] tanks...

Best wishes achieving resolution.

Cheers, Bill

PS: No, it is not normal for older boats to smell like a head...

[Shrew]

When was the last time the sanitation hoses were replaced?

The most common cause for this issue is weeping on old hoses. Even the absolute best hose (Raritan) is only a 10 yr hose. Most are much less.

[markxengineerin]

I do not have the book, trying forum wisdom first, but I'd like to get a copy.

The hoses are 1 year old, but the cheap ones, all I could source at the time. I hoped that covering them in aluminum tape would prevent permeation, the stuff has been good in other applications and I'm still not certain it has failed here.

When a hose says it's good for 10 years, does this mean with sewage in it, or can no flexible hose handle that?

I am considering a complete re-design of the head system at this point- I have wasted a lot of time and energy replacing every hose, rebuilding the tank, rebuilding to toilet itself, and it still smells. I don't know what Pacific Seacraft was thinking, 15 gallons isn't big enough in the first place.

[s/v Jedi]

If the tank connections, inspection hatch etc. are all sealed properly then it’s the hose, valves, vent etc.

Not having the non-permeable hose is a big red flag. Vetus sells a good one, as does Raritan.

[Shrew]

Originally Posted by markxengineerin

The hoses are 1 year old, but the cheap ones, all I could source at the time.

I wouldn't think a 'non-permeable' (more like temporarily non-permeable) sanitation hose would start weeping so quickly.

What type of hose did you use? wet exhaust hose or heavy duty multi-purpose hose would be problematic.

[markxengineerin]

It was sanitation hose, I think most of it was "Shields" brand, or another that looks identical in construction. Typical to find in stock at any marine supplier. When I ordered, I thought I was ordering the good stuff w/ metal wire inside, but miscommunication w/ the vendor and it was too late to change plans.

[s/v Jedi]

Originally Posted by markxengineerin

It was sanitation hose, I think most of it was "Shields" brand, or another that looks identical in construction. Typical to find in stock at any marine supplier. When I ordered, I thought I was ordering the good stuff w/ metal wire inside, but miscommunication w/ the vendor and it was too late to change plans.

You need odor shield hose, like SaniFlex, Vetus etc. They come with something like a 10 year odor warranty. It isn’t about a metal spiral.

But the source can be at a Y valve etc. If you can temporary connect straight into tank to test, you get some answers.

[markxengineerin]

Right, i know the wire isn't the critical part, but the good odor shield hose I've seen and thought I was ordering has had the wire. Y valve is a groko solid bronze, new.

10 year odor warranty- valid even if effluent sitting in hose? Can anyone report success in a poorly plumbed system like mine, but with good hose?

[peghall]

You cannot eliminate any odor until you've eliminated the source...and odors are always strongest at their source. You may have multiple sources, each one generating a similar but slightly different odor and not all boat odors are in your head. For instance a sump or bilge in serious need of cleaning is primordial soup that can make an entire boat smell like a swamp or even a sewer. And just dumping in some bilge cleaner, swishing it around a bit, then turning on the bilge pump(s) and calling the job done will not give you a clean bilge, any more than just pouring dishwashing liquid into a sinkful of dirty dish water, swishing it around a bit and then pulling the plug will give you a clean sink.

Your sanitation hoses are another possible source...don't guess, test them: wet clean rags in HOT water--as hot as you can handle...wrap a clean rag around every section of hose. When the rags have cooled, remove each one and smell it. no odor on that rag, that section has not permeeated. If you can smell anything on that rag, that section of hose has permeated....new hoses are the only cure.

Residual odor from previously stinky hose can permeate the inside of lockers or other areas it passed through...requiring serious cleaning with detergent and water followed by an odor-eliminating treatment.

Those are some of the most obvious sources...there are others. Put your nose to work hunting them.

--Peggie

[SailingHarmonie]

I don't get it.

We have hoses on our boat that are original factory install. Have been in full time liveaboard use for >25 years. Sit full of waste for 24/7/365.

They don't smell. They pass the wet paper towel wipe test. There are no sewage odors--ever--inside the boat, unless we have a leak or other mechanical problem.

Must be magic.

[markxengineerin]

All of the above makes me think something else is wrong, that it's not the hoses. Hard for me to test them for a valid conclusion when they're foil wrapped.

I would eat out of the bilge, it's super clean and doesn't smell at all. I keep it dry minus about a cup of water that the "dry bilge" system can't quite reach. The odor is coming from the cabinets containing all the plumbing, and it is far worse in the act of discharging overboard w/ the macerating pump, for whatever reason. Is it possible that this pump is permeable to odor? Also new 1 year ago.