Unpleasant question re heads...

Sea-Fever

Sea-Fever

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I'm planning to fit a holding tank. One problem as I see it is that with a toilet below the waterline (which will be most installations) and the subsequent need for a swan neck of outlet pipe before joining the outlet seacock (or a holding tank), there will always be an 'uphill' section for your produce to navigate before headwind down and out through the seacock.

Is this why heads pipes tend to smell and is there anyway round this problem?? It is unsavoury to think of 'stuff' sitting in the pipe ....even if you do thoroughly flush.
 
Sea-Fever said:
Is this why heads pipes tend to smell and is there anyway round this problem?? It is unsavoury to think of 'stuff' sitting in the pipe ....even if you do thoroughly flush.
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Yes, any normal installation is going to need an upward section. There shouldn't be more than trace amounts of crap in it once you've finished flushing though - it should be followed by the paper and then by sufficient water to displace everything out of the boat or into the tank - the figure for a standard Jabsco is 7 pump strokes per metre of pipe, so 20 strokes in my case, starting after the last bit of pee or paper has left the bowl.

The commonly used white PVC pipes are somewhat permeable and can smell after enough time in use. I use - and would recommend - ASAP's grey butyl multi-layer hose instead. After six years of regular (albeit not live-aboard) use since fitting them, mine are 100% smell free and the heads compartment is a perfectly pleasant place to be. The hose is also easier to fit than the PVC type since it's significantly more flexible around corners and stretches over the hose barbs more easily. The inside is very smooth and slippery which might help in avoiding blockages. The downside is that it's substantially more expensive than the basic PVC spiral type, but totally worth it in my opinion.

Pete
 
A properly fitted unit shouldn't smell. I have a holding tank above the loo and something of an uphill loop. If you don't pump fully in any system you will only have the joker valve and the one in the pump to hold back the soil and I don't think the addition of a holding tank should make any difference, though you may be adding to the head of pressure. A shut-off valve on the tank should take care of this.
 
Good quality heads hoses should not smell unless they need replacing. The only way to clear the uphill stretch is to do a lot of pumping although you should do this to prevent scale build-up in the hose. The problem if you are on the holding tank is that you soon fill it up. :(

Richard
 
Sea-Fever said:
I'm planning to fit a holding tank. One problem as I see it is that with a toilet below the waterline (which will be most installations) and the subsequent need for a swan neck of outlet pipe before joining the outlet seacock (or a holding tank), there will always be an 'uphill' section for your produce to navigate before headwind down and out through the seacock.

Is this why heads pipes tend to smell and is there anyway round this problem?? It is unsavoury to think of 'stuff' sitting in the pipe ....even if you do thoroughly flush.
Click to expand...

Try not to think about it. Do your business, pump it out thoroughly and get on with life.

If the thought of any of your own recent activities sitting in the pipet troubles you it will be advisable not to think about everything "discharged" by the other crew members sitting in the holding tank since the last time you emptied that!
 
LadyInBed said:
If you always use the holding tank, is there a reason why the tank can't be plumbed before the anti syphon loop?
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A tank and its breather vent form an extremely effective anti-siphon system - if you use the nice simple design that always passes through the tank then no separate anti-siphon valve is needed.

Pete
 
Having had to clear holding tanks and pipework blocked with tissue pulp far too many times, I can once again recommend not putting it down the head in the first place.

Cue usual suspects who have never cleared a blockage........
 
capnsensible said:
Cue usual suspects who have never cleared a blockage........
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...who have never had a blockage :)

To be fair I don't have a holding tank, which makes things simpler. It's one length of smooth-wall pipe from pump outlet to skin fitting, broken only by the anti-siphon fitting which is a wide curve of smooth plastic. There's no conceivable way for matter that can get through the toilet itself to then fail to make it to the sea. A rigid stick like a short length of kebab skewer or something could perhaps wedge itself against the end of a hose fitting and start a blockage, but nothing like that will be going down the heads.

Pete
 
I have only once ever had a blockage and have never had paper down it since - sailing in Greece it didn't seem unnatural to us a bin by the loo anyway and still doesn't.

As Richard says above you shouldn't flush lots and in my view should flush using the absolute minimum of water that will clear the bowl. The uphill pipe will add litres to your holding tank capacity which should be filled with sewerage not fresh sea water and the head of pressure actually helps keep the joker valve shut. The alternative is to fill it too quickly as I once found when all but one person was swimming and the breather pipe was half over the water and half over the dinghy.

So maintenance is to always flush through a lot after opening the holding tank to the sea, change the joker valves as often as needed and to change the pipe when there is a hint of a smell. For me that's a joker valve or two per year and a pipe every 3-5 years. I mark each pipe with the last month and year I changed it as it's otherwise something I'd happily forget.
 
johnalison said:
Be my guest. There is a nautical equivalent of Godwin's Law that states that any conversation between sailors will include a reference to holding tanks within 20 minutes.
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I've no idea why people argue - as long as they are gravity drain then they are simple and brilliant and mean you almost never have to wander up to the marina loos again.
 
RupertW said:
I've no idea why people argue - as long as they are gravity drain then they are simple and brilliant and mean you almost never have to wander up to the marina loos again.
Click to expand...

I entirely agree. I wouldn't wish to be reliant on pumping out. A friend bought an ex-demo Island Packet. We were cruising in company for his second year, when the outlet to the tank was blocked and there was no alternative. With six on board he had to find a pump-out every two or three days, which gave us much entertainment. (The blockage was caused by a kitchen wipe, present from before he bought the boat).
 
prv said:
Yes, any normal installation is going to need an upward section. There shouldn't be more than trace amounts of crap in it once you've finished flushing though - it should be followed by the paper and then by sufficient water to displace everything out of the boat or into the tank - the figure for a standard Jabsco is 7 pump strokes per metre of pipe, so 20 strokes in my case, starting after the last bit of pee or paper has left the bowl.

The commonly used white PVC pipes are somewhat permeable and can smell after enough time in use. I use - and would recommend - ASAP's grey butyl multi-layer hose instead. After six years of regular (albeit not live-aboard) use since fitting them, mine are 100% smell free and the heads compartment is a perfectly pleasant place to be. The hose is also easier to fit than the PVC type since it's significantly more flexible around corners and stretches over the hose barbs more easily. The inside is very smooth and slippery which might help in avoiding blockages. The downside is that it's substantially more expensive than the basic PVC spiral type, but totally worth it in my opinion.

Pete
Click to expand...

Thanks for recommendation Pete.... I'll look into the ASAP pipe....i see they are back up and running now.
 
RichardS said:
Good quality heads hoses should not smell unless they need replacing. The only way to clear the uphill stretch is to do a lot of pumping although you should do this to prevent scale build-up in the hose. The problem if you are on the holding tank is that you soon fill it up. :(

Richard
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I can't see it getting too full....it's only really a stop gap for those occasions when we can't be bothered to use the marina loos prior to leaving for open water....if I'm at the boat it generally means I'm going to go somewhere....i don't treat it as a static caravan.
 
Sea-Fever said:
I can't see it getting too full....it's only really a stop gap for those occasions when we can't be bothered to use the marina loos prior to leaving for open water....if I'm at the boat it generally means I'm going to go somewhere....i don't treat it as a static caravan.
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For most of us it's not marinas or open water that are the problem ..... it's when you're at anchor in a bay with other boats that a full holding tank which is spraying out of the vent becomes a pain in the arse .... both for you and everyone else in the bay. :ambivalence:

Richard
 
Also, don't confuse the smell of the output with the smell of the input!
Sea water left in the inlet pipes can generate hydrogen sulphide when the heads is used again after a few days of non-use. This is due to "animals" in the sea water degrading. It goes quickly once flushed through.
 
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