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Joined: 01 Nov 2006
Posts: 12
Location: sweden

Smell from toilet   Posted: Mon 12 Feb 07, 16:13    Reply with quote


I have a problem. My boat smells like s**t. I know where it comes from.

I dont know why. And I donīt know how to fix it.

Anyone with similar problems?

Anyone with a solution to the problem?

PS . There is a holdingtank onboard

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Joined: 20 Feb 2007
Posts: 15
Location: UK,Chester

Re: Smell from toilet   Posted: Tue 01 May 07, 9:58    Reply with quote

A common problem when you get a smell from a toilet/holding tank is the large diameter pipe which goes from the toilet to the tank/outlet becoming slightly porous. They do this with age, it is unavoidable. To determine if your hose has become porous, do this...

Find a cloth rag and dip it in water as hot as you can hold. Squeeze out the most of the water. Wrap the hot damp cloth round the large diameter pipe, holding it there for a minute. Unwrap the cloth and smell it. If it smells bad, you have a porous pipe, and the only solution is to replace it.
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Double Horizon

Joined: 09 May 2007
Posts: 428
Location: USA

Solving Toilet odors   Posted: Mon 14 May 07, 1:51    Reply with quote

My investigation indicates these odors are caused by anaerobic bacteria and decomposing organic material. If there was proper ventilation in the system you would not have a problem, because aerobic bacteria would eliminate the smell.

In the toilet intake you have sea organisms that die in the hose when the system is not used. If you leave the intake valve open you would reduce the problem because the hose would be open to the sea, but that leaves your boat at risk of flooding in case of hose failure (check your clamps regularly). The best solution (not practical in most Dragonflies because of limited water capacity, unless equipped with desalinator) is to flush with fresh water, so there are no sea organisms in the toilet. (This could be done without causing back-flow to the fresh water tank by hooking the toilet intake to to the drain of the sink with a Y-valve, and filling it with fresh water before flushing). The sea organisms are as much of the problem as the human waste.

The same sea organisms are combined with human waste in the hose between the toilet and holding tank. Same issue here. You would have an improvement if you could re-route the hose so the highest point were near the toilet, and the remainder were down-hill to the holding tank (with no low spots to trap waste) so the hose would sit empty. Unfortunately the design of the 920 doesn't make that a practical solution. However, the hoses used by Quorning are OdorSafe hoses of the highest quality, and the permeation of the hoses is not likely to be a problem for many years. So I would concentrate effort on the tank.

The 920 (and other boats from almost all makers) has a small diameter holding tank vent (1/2" or 3/4"). Boat makers seem to think the only reasons for a vent are to relieve pressure and vacuum. That is only part of the desired function. Ideally you want a larger vent (at least 1 inch diameter) and preferably two vents (one exiting each side of the hull) for cross-ventilation. You need good tank ventilation so aerobic bacteria prevail, which will neutralize odors from the tank. Do not use a vent-line filter as it would reduce air flow and make matters worse.

Other than leaving the intake open (I acknowledge the risk), here is what you should do: Check your existing vent to make certain it is not blocked by water, waste overflow or insects. Make sure it has no low points or sags anywhere between the ends, because that would cause water or waste to block it. Add a second vent of at least 1-inch diameter for cross-ventilation and route it so that the outlet is on the opposite side of the hull from the factory vent. I think you must add the second vent hose to solve this.

Quorning uses a sticky gray sealant on the tank top fittings and aluminum cover, and I recommend butyl rubber sealant (it has similar properties) common here in the US for roof sealant. Butyl rubber stays sticky and will allow the parts to be separated again without damage (you need a sealant, not adhesive).

I did a lot of research on this and the best information source I found was this book: Get Rid of Boat Odors: A Boat Owners Guide to Marine Sanitation Systems and Other Sources of Aggravation and Odor http://www.amazon.com/Get-Rid-Boat-Odors-Aggravation/dp/1892399156/ref=pd_sxp_f_pt/102-4515852-0836156

Peggie Hall is the author and she will also answer questions by email. Search for her name on the web and you will find she participates in discussion groups. (I would not post her email address.)
Larry - DF-1200 Double Horizon
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