Toilet, how to get the seawater out of the inlet pipe

RichardS said:
I can't say that I'm aware of anyone who has specifically said that. ...
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JM did back at #15 (‘It's not the plankton. Try putting some seawater in a bottle and leave it lying about for a few days. It doesn't smell’), disagreeing with geem at #14.

john_morris_uk said:
I remember the experiments and the discussions. Point taken regarding ANY source of organic matter.

I look forward to seeing the results of your experiments in due course.
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I have not had the opportunity, and it’s not a high priority for me. (I guess I could have a go here at home with a teaspoonful of grass clippings in a bottle of tap water and a dash of Epsom salts to provide the sulphate ...:ambivalence: ).

I’m not trying to be awkward, and do accept that faecal cross-contamination (within the pumping system, or from external ‘short-circuiting’) may often be – perhaps most often is – the cause of rotten egg odours, but insistence that it must be so could be unhelpful. People encountering a brief (I do stress that) whiff of rotten eggs on first flushing the heads after a long absence might start to think that their pump needs servicing when perhaps it did not – and any idea that faecal matter might be getting to the wrong place rightly concerns people, of course.
 
RichardS said:
John didn't say that "faecal material specifically is essential to produce the rotten-eggs odour". He just said that plankton is insufficient. ;)

Richard
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Not in those precise words, but he said a little more than you imply with your ‘just’:

john_morris_uk said:
It's not the plankton. Try putting some seawater in a bottle and leave it lying about for a few days. It doesn't smell.

The smell is from effluent either being circulated back into the inlet pipe from the discharge underwater or leaking past the piston in the pump.
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From John’s response at #38 I did not think I had materially misrepresented the gist of his post, but if I have since in #41 he has my apologies of course.
 
The rotten eggs smell on first pumping the heads after a week or two unused happens often enough to enough boats/people for a fix to be useful. Either an expensiveish patent gadget like the American one quoted earlier or a Leesan gadget ( https://www.leesan.com/uploaded_files/datasheets/seaseamart-15.pdf ) will fix it. A £10 Jabsco round filter in the middle of the inlet pipe with a 50p domestic toilet block inside - changed every month or two - also fixes it.

Most of the "fill inlet with fresh water" options involve valves and are not always idiot-proof. If you are lucky enough never to get the smell then fine, but I bet most people do eventually with most standard marine WC installations.
 
jwilson said:
The rotten eggs smell on first pumping the heads after a week or two unused happens often enough to enough boats/people for a fix to be useful. Either an expensiveish patent gadget like the American one quoted earlier or a Leesan gadget ( https://www.leesan.com/uploaded_files/datasheets/seaseamart-15.pdf ) will fix it. A £10 Jabsco round filter in the middle of the inlet pipe with a 50p domestic toilet block inside - changed every month or two - also fixes it.

Most of the "fill inlet with fresh water" options involve valves and are not always idiot-proof. If you are lucky enough never to get the smell then fine, but I bet most people do eventually with most standard marine WC installations.
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Yes, I got an inline gadget many years ago (it was on very substantial reduction!) but now just use a standard domestic block in it – works fine for me, but I never had much more than a brief odour on first opening anyway.
 
jwilson said:
The rotten eggs smell on first pumping the heads after a week or two unused happens often enough to enough boats/people for a fix to be useful. Either an expensiveish patent gadget like the American one quoted earlier or a Leesan gadget ( https://www.leesan.com/uploaded_files/datasheets/seaseamart-15.pdf ) will fix it. A £10 Jabsco round filter in the middle of the inlet pipe with a 50p domestic toilet block inside - changed every month or two - also fixes it.

That's the best answer so far :)

Most of the "fill inlet with fresh water" options involve valves and are not always idiot-proof. If you are lucky enough never to get the smell then fine, but I bet most people do eventually with most standard marine WC installations.
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Smelly heads intakes are a relatively new phenomenon, and easily fixed.

Throw away your roller reefing; change your synthetic sails for canvas, your synthetic ropes for hemp, and your Goretex clothing with proper oilskins; replace your LED lighting with oil lamps, and your gas stove with paraffin. For good measure smoke a pipe, and you'll not need to worry about the problem again! ;)
 
LittleSister said:
Smelly heads intakes are a relatively new phenomenon, and easily fixed.

Throw away your roller reefing; change your synthetic sails for canvas, your synthetic ropes for hemp, and your Goretex clothing with proper oilskins; replace your LED lighting with oil lamps, and your gas stove with paraffin. For good measure smoke a pipe, and you'll not need to worry about the problem again! ;)
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After 3 pages I decided that it was much simpler to put up with a bit of pong for a minute than do anything. I'm not interested in what causes the pong, it's not a big deal. I have sailing to do.
 
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An interesting read, I also get a whiff of rotten egg smell with the first flush after leaving the boat for a few days and I have narrowed it down to the inlet pipe seawater microbes who use up all their oxygen then die and rotten in the absence of oxygen. I can't see any other possibility since we have never done number 2 in it and the possibility of faecal matter cross contamination is ruled out.
 
benchmark said:
An interesting read, I also get a whiff of rotten egg smell with the first flush after leaving the boat for a few days and I have narrowed it down to the inlet pipe seawater microbes who use up all their oxygen then die and rotten in the absence of oxygen. I can't see any other possibility since we have never done number 2 in it and the possibility of faecal matter cross contamination is ruled out.
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Is that because you never do No 2's in your boat loo?
 
benchmark said:
An interesting read, I also get a whiff of rotten egg smell with the first flush after leaving the boat for a few days and I have narrowed it down to the inlet pipe seawater microbes who use up all their oxygen then die and rotten in the absence of oxygen. I can't see any other possibility since we have never done number 2 in it and the possibility of faecal matter cross contamination is ruled out.
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This is the correct answer to what all the above fuss is about. All the other suggestions are nonsense, If you shut the inlet seacock the water is trapped so that's what happens. If you leave the seacock open I imagine the uphill bit will empty and possibly reduce the pong a bit ... personally I like to shut the seacock when leaving the boat for a week.
 
pvb said:
Interesting. So how would it happen when the toilet is being discharged into a holding tank? And how would water "leaking past the piston in the pump" find its way into the inlet pipe?
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The cause of the smell is certainly not exclusively your own sewage leaking back into the inlet pipe and pump. A couple of years ago, we left the boat unused for several weeks and then, on starting the engine, discovered that the cooling water intake was blocked with weed etc. I closed off the inlet stopcock and opened the cooling water strainer in the engine bay to clear it - the smell was strong and exactly the same as you would get from a heads that had not been flushed for a while. And there is a significant distance between our heads outlet and the cooling water inlet. It may well be true that a bottle of clean sea water does not smell after a couple of weeks - I have not actually tried the experiment - but sea water in a confined space with marine life other than human sewage certainly can generate the hydrogen sulphide smell that we all know and hate.
 
maby said:
The cause of the smell is certainly not exclusively your own sewage leaking back into the inlet pipe and pump. A couple of years ago, we left the boat unused for several weeks and then, on starting the engine, discovered that the cooling water intake was blocked with weed etc. I closed off the inlet stopcock and opened the cooling water strainer in the engine bay to clear it - the smell was strong and exactly the same as you would get from a heads that had not been flushed for a while. And there is a significant distance between our heads outlet and the cooling water inlet. It may well be true that a bottle of clean sea water does not smell after a couple of weeks - I have not actually tried the experiment - but sea water in a confined space with marine life other than human sewage certainly can generate the hydrogen sulphide smell that we all know and hate.
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This is correct. Also if you add heat into the equation the development of the eggy smell is significantly quicker.
 
john_morris_uk said:
Is that because you never do No 2's in your boat loo?
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Correct, my boat loo has never had faecal matter in it , we use the marina toilets , the boat septic tank is still as dry and empty as the first day it came out from the factory. We do pee in the loo with direct flush into the sea but that's all, otherwise it's reserved for emergencies only which to date have not happened.

Hence , the faecal matter cross contamination theory as a reason for the rotten egg whiff does not apply in my case.
I have noticed that if I close the inlet valve, the first flush water stinks after 24 hrs. If I leave the inlet seacock open it does not smell.

I would rather close all seacocks anythime I leave the boat so I am also looking for a permanent solution and the Jabsco filter guard with a urinary block seems tempting.
 
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'I have noticed that if I close the inlet valve, the first flush water stinks after 24 hrs. If I leave the inlet seacock open it does not smell.'

That's interesting, my jabsco is stored on a trailer during the week with the seacock left open and only used for the weekend, no. 1 & 2's. Rinse it out with fresh water at the end of the weekend.

So the smell has to come from the 1m downward pipe / pump.
Unless the empty inlet part creates a smell ...
 
Just back from our 15 week cruise, so only just picked this thread up.

From direct experience, our previous boat had a long inlet pipe-6 metres plus-and we suffered the smell. This long pipe was because the heads inltet and engine inlet were shared and used the same seacock and inlet strainer. Engine aft, heads forward, hence long pipe.

Current boat, from the same manufactuer has its own inlet seacock and strainer, alongside the heads. Only about a metre of inlet pipe.

The smell is insignificant.

Every time the boat is left for more than a few days the bowl is pumped dry, white vinegar-about 3 litres-is poured in and pumped through the system and then the exit seacock is closed. The bowl is topped up to the top of the outlet pipe.

When we return and prepare the heads for use the slight smell of vinegar overpowers any other smell and is certainly more pleasant than the rotten egg smell.

The white vinegar is cheap-14 quid for 20 litres off ebay-and keeps the bowl and outlet pipe clear of build up.

My 2 pennyworth anyway..................
 
rotrax said:
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When we return and prepare the heads for use the slight smell of vinegar overpowers any other smell and is certainly more pleasant than the rotten egg smell.

The white vinegar is cheap-14 quid for 20 litres off ebay-and keeps the bowl and outlet pipe clear of build up.

My 2 pennyworth anyway..................
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Hmmm, like the idea of the vinegar for cleaning the outlet pipe!
 
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