You cannot stop the bacteria growing in the salt water of the inlet pipe, and this is what causes the rotten egg smell (sulphur something or other can't remember my chemistry lessons now)

On Hullabaloo, I have plumbed the for'd sink drain into the toilet inlet pipe, I fitted a new sink a few years ago and didn;t want to put another skin fitting in the hull.

This has several advantages (there is a ball valve between the sink and the loo inlet pipe)

1) I don't have to worry about water syphoning up the sink drain and into the boat when heeled or in a rough sea - the ball valve is shut and that is that.

2) to empty the sink (on either tack) one opens the ball valve) pumps the loo (flush) and the sink is pumped empty with the contents going out via the loo.

3) When leaving the boat for a day or so I fill the sink with fresh water, add a bit of disinfectant, (Mr Ecover's yellow coloured stuff is preferred) , close the loo inlet seacock and pump the contents of the sink out and through the loo.

I have nice clean dinifected water throughout the inlet side of the loo (plus quite a bit sitting in the outlet pipe as well I expect) and therefore no smell at all, even after a winter laid-up afloat.

Not only that but with fresh water in the loo system, it does not scale up with salt, so I never have to strip the loo etc. It's been like this for ten years and I've had to do absolutely no maintenance on the loo and it still looks new! (and stripping loos really is the worst job on the boat!)

Hydrogen sulphide I think David. (H2S)

The biology is natural. We close off the bog system to oxygen when we leave the boat. The aerobic bugs use up the available O2 then die. The anaerobes then get going. Their waste product = hydrogen sulphide (good ol stink bombs)

White vinegar for de-scaling.

As you advise, a basin full of fresh water for the final flush before closing the sea cocks.

I would suggest you take the inlet pipe to you fresh water tank via a non return valve this will solve all your problems until you move your inlet skin fitting,I have done this for a number of boats with great success & very little increase in the use of your fresh water,I have just fitted a new Jabsco to my motor boat they are superb with the locking pump.

If you need any more tips on how to do this just blog it & will get back to you. 

Yuk.  I don't think I would want a direct connection between the toilet pump and the FW tank. Even via NRV's

I think sometimes a smell problem may be exacerbated, if not caused, due to insufficient pumping to ensure complete clearance of foul water not only from the bowl but all the pipework plus sufficient  rinse pumping.  It is worthwhile checking how many strokes are required to clear the pipework and appending it to the heads instructions. 

There is no conexion between the fresh water and anything else once you have pumped

if you are worried put a long loop in the inlet pipe so NO possibility of a 'flowback' the nrv

is just good practice like double clips..........

I'm gobsmacked! If your boat was being run as a commercial operation in this port it'd be detained.

I have 2 lavac sea toilets on my boat and niether of them smells, I use ecover toilet scleaner in them and whenever I leave them and find that this works ok even with seawater left in the bowl. About twice a year I put about a cup full of mineral oil into the bowl and slowly flush it through to lubricate the pump.

I think generally if you keep on top of maintenance and cleaning and ensure that the heads space has some ventillation you can ovoid the unpleasant odours, or at least minimise the resultant effects.

The difference with the Lavac, is that it is pumped with the lid sealed shut by the vacuum and all the smells get sucked out that way, one only opens to lid to "Go" so you'll never experience the nasties!

It seems that the Lavac might well be the best solution to this problem.

One word or warning though - remind vistors that they must never pump the loo when sitting on it!

A few years ago (well 25 at least) a Yacht Club which used Lavacs had a middle aged woman who unfortunately pumped whilst sitting! She suffered a prolapsed womb (no I wont describe it!)  

wonderful, thankyou for sharing that with us......................

Share the comments about having the inlet forward o the outlet. In my boat ( Sigma 33) ther is abouta metre between the two.

I'm told if you want absolutely to about the initial rotton egg smell that you should change the hoses to "food grade" as this prevents the problem. You've guessed though that the catch is that it's even more expensive than the marine grade.

A couple of years ago I fitted a Yachticon Puritec head treatment system to the toilet ( a humble RM69). Effectively this is a dissifectant / cleaner contained in a 100ml bottle that screws into a tee piece that you insert in the inlet water pipe. Costs about a tenner , refill about £7 and lasts about a season. It's probably the equivilent of the Loo Blu type blocks that you use at home.Takes about 5 minutes to fit.

Probably one of the best low cost things I,ve fitted on the boat. Definately cuts down on smell, each flush of water has a pleasant smell, Blue dye seems to add some element of comfort, and it definaltely make an  improvement in keeping the bowl clean.

I've recomended to a few people who having fitted all agree it's good.

if you do fit one, just remember to remove if your ashore in winter as the bottle can freeze and pop the bottle out of the tee piece damaging the threads and makes it a possible source of leaks. 

TMS reader John Nuttall has been in touch to add:

"Now 63 years old and put many sea miles in on sailing yachts over the years. I was told how to stop your toilet from smelling many moons ago by an old friend. Have used the below method ever since and never had a smelly toilet since. I am either very lucky or the method works.

This is what I and many of my friends do. As you say keep the workings clean. (just like you would at home) Do not use bleach as it rots the pump seals.

After the toilet has been used pump all the contents out. Usually with the lever in out position. In position two pump in sea water to flush. Turn off the inlet seawater seacock. Then put some clean fresh water into the bowl and pump out in the first position but leave a little water in the bottom to stop any smell coming from the u bend.

This will usually stop the smell. The draw back is the use of fresh water when on passage. The question being do you want a bad smell or can you spare the water? When at a marina there is no problem with the fresh water. I use the shower to put water in the bowl.

Love to know if anyone else tries and succeeds?"

If you are worried about connecting the suction line to the water tank and this conexion should be made before the pump.........take a 20/25 litre spare drum full of fresh water re-connect the toilet to this 'spare' Tank & you will see the smell disappear,whatever you do filling the bowl with fresh water is the only answer long term if you require any more info send me a contact via the mainsail & I will send you drawings etc..............L

Reading all these racent contributions some seem to miss the point that the smell is generated by bacteria in the inlet tube.

And yes...i am short of something to do at the moment!

I have not missed the point at all the ONLY way to stop bacterial growth in the inlet tube is to use  fresh clean water & not seawater pumped in from near the outlet.

All other meathods are a mask not a cure.This is my last comment on this subject..............L

Laurie

I Don't think you've got the point!

The issue is one of ensuring that one has fresh water in the inlet pipe when the boat is left for several day without the loo being pumped. There is no reason to not use salt water when it is being flushed several; times a day, As we can all attest from when we are away on hols!

The solution t the smell is to get freas water into the inlet pie when the boat is left for a few days - hence my method of using the loo to suck a sink dry.

Putting some anti-bacterial agent into the water helps a bit as well! As the water in the pipe will be slightly brackish.

Try my method and you'll never have a smell ever again!

This is getting silly all that is needed as you say is fresh water a few drips of milton before you leave the

 boat in the final pump will ensure no smells on return or turn of the inlet & pump dry before leaving

 no more smells 

 PS I have lived on boats for 15yrs...............L 

Coo!  Take it easy guys!  Why is it that any innocent and informative article gets people so over emotional?  Share ideas - try 'em - use what works.  All bogs are different - mine no exception. 

But I swear a drop of Dettol after use works wonders!