Smelly Y-valves

[sailingterp]

Greetings CF! I am a newbie here but have done my fair share of reading the posts and figured it was time to jump on in the fun.

I bought my Oday 35 last year and the PO had done a major refit on many of the systems only 3 years ago before cruising in the Bahamas, including the whole plumbing system. Even though everything looks ok and there were no visible leaks when we were using the system last summer and fall, we had the nasty smell coming from under the vee where the 20 gallon holding tank is located. Even now after being dry docked all winter I can still smell it.

All of the hose looks new-ish and appears to be sanitation hose. There are Y-valves and a manual pump for pumping out the tank offshore also under there and I was wondering if those could be the culprits. I have not done the rag testing yet but plan on getting to the bottom of this before too long. Anyone have any experience with smelly valves or pump? I read on the forum it is most likely not the tank since it is vented. Could it just be the hose even though it is sanitation hose and only 3 years old?

[David M]

If it is true sanitation hose (the white stuff or the black rubber hose that is labeled sanitation hose), then that is not the source of the smell.

Is there perhaps a very slow dip coming from the seals of the Y-valve or a very slow drip coming from where a hose clamp is not tight enough? Also check the vent line.

Perhaps there was a leak in the past that you are unaware of? A solution of bleach, liquid laundry detergent and hot water can help kill that smell.

Double clamp all your hoses with solid wall hose clamps, not perforated wall, if you have the room.

[MarkJ]

Bleach, then CLR (Calcium, Lime Rust) in a can from the hardwear store. Pump it through at full strength and leave it in for half an hour then flush out with copious amounts of fresh water.
Seperatly, of course, don't mix the bleach and CLR... I think that's one of those mixtures that go bang....

I am not a believer in vinigar. Three years of gunk is not going to be removed by distiller wine! Put in CLR and you stand a chance.

Mark

[boatpoker]

Even the best sanitation hose will eventually permit thru-gassing which I why we switched
all waste hose to ABS pipe many years ago. Make sure your vent line is clear.
What is the tank material ?

[cfarrar]

I doubt a nylon-type valve would smell much. I'm not sure about the hand pump. I suppose it could smell with a synthetic, rubber-type diaphragm exposed to the air.

Yes, hoses can become permeated after a few years, especially if the PO made a habit of not flushing the lines completely after each use. Try the rag test. Changing the hoses is not hard. Personally, I'd do this, clean every corner of the bilge, and ensure the tank is adequately vented.

[sailingterp]

Make sure your vent line is clear. What is the tank material ?

I think it's polyethylene. I have the paperwork I think so I can try to see if the tank material is permeable.

I am pretty sure the vent line is clear since I remember in the heat of the summer standing on the finger pier next to where the vent is located outside the boat and getting a strong smell from there. I figure that means it's working!

If it is true sanitation hose (the white stuff or the black rubber hose that is labeled sanitation hose), then that is not the source of the smell.

It is the white stuff and all connections are double-clamped. They might be the perforated hose clamps, I am not sure.

Changing the hoses is not hard. Personally, I'd do this, clean every corner of the bilge, and ensure the tank is adequately vented.

It's not the job of changing hoses that I am avoiding, just the expenses when there is so much of it because of the different ways to direct the discharge!

I guess I will try one of the cleaning methods recommended and check all of the hose clamps. While I am at it I will double check the vent line. Do you just put all this stuff down the head to get it into the system?

[boatpoker]

One of the problems with a polyethylene tank is that all the connection fittings are hard plastic. The softer poly expands and contracts at a different rate allowing out-gassing. Many people try to saolve this with caulking of one kind or another and it does not work because none of it will stick to the poly.

If this is the case, best chance is Teflon tape on the threads.

[cfarrar]

Terp,

I guess some peoples' sanitation hoses last for decades, but I got "that smell" when my boat (and hoses) were about 5 years old. I looked for leaks and cleaned every crevice in the bilge. No joy. After putting up with it for a couple of years, I changed the hoses. Problem solved -- wish I'd done it sooner. Anyway, hopefully you find a cheaper fix. Let us know.

[Watercolor]

I’m assuming you did a through pump out and flush on the system. Could anything have been put into the tank during storage?

If the tank is clean and because the smell presists.

1. Check for leaks at all the fitting connections.
2. Wipe down all the hoses and smell, especially those that are below the level of the tank top. The line sections below the tank top are the ones that will have had standing waste in them. Over time the smells will permeate the hoses. Three years is a short time for that to occur, but give it a try.
3. Do the same for all the hose fittings that are below the tank top. Contrary to earlier comments nylons, nylon can be a real cause of smells. Nylon is hydroscopic and absorbs much more moisture than any plastic used on a boat. Black fittings are most likely nylon. They’re either Marine East of Forespar fittings. There are also very cheap white (not PVC white) nylon fittings. Forespars nylon will absorb over 7% of its weight in moisture within several months, the other nylons probably over 8% in an even lesser time.
4. If the y-valves are Forespar valves (nylon) and are below the waterline, do the wipe test. PVC, ABS, polypropylene or polyethylene are quite moisture resistant. And should not be a cause of your smells, but can leak.
5. The tank is most likely polyethylene and shouldn’t smell. However. They are not overly strong and can crack at the welds and the fittings. I’d give the tank area a good looking over. If there is a crack, in addition to replacing the tank, I’d make sure the new tank well supported and locked down.
5. If your tank has a side mounted vent port. And if the line dips down or is flat for a distance waste material can build up there and clog the line. I’d give that a good checking over and check the line for smells.
6. I don’t know if the liming smells, but as someone mentioned, it can’t hurt to clear the line.
7. Again, as someone mentioned, the fittings may not have any teflon tape or paste and may leak.
8. The only other possibility I can think of is to see it any of the lines have a vented loop. If it’s stuck open it might be possibly the problem.

Hope that helps.

Fair winds