As I explained in my previous posting, the Beneteau 361 has a very poor sanitation design with its holding tank top located about 4 ft above the base of the head. So, no matter what you do, after flushing there is always quite a bit of stuff (half a bowl) remaining on the tube. To make things worse, the tank has an additional 3 ft tube that runs from the bottom of the tank to a through hole for emptying it to sea and a third tube that runs from the tank's bottom to a deck fitting for pumping out. And, yes, there is a fourth vent tube running from the top of the tank to a through hole above the water line. The only advantage of the system is that it can be emptied in high seas without active pumping. Whoever, as you have predicted, because stuff remained on three of the tubes to and from the holding tank the tubes permeated a bad smell in less than 6 months. Based on your teachings, I was faced with the task of either, changing tubes very often, pumping out every day or changing boat. Fortunately, I discovered that by wrapping aluminum foil around the tubes, the smell from the permeated tubes could be completely eliminated. I found at Homedepo aluminum tape about 5” wide that has one sticky side and can be easily wrapped is short sections around the smelly tubes. I did the repair last winter, and the smell totally went away to never return. If the tubes are accessible along their length, this solution may save a lot of time, money and frustration to our fellow boaters.
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You wrapped the hoses in duct tape???
That's a first!
)) However, "gone, never to return???" Don't count on it. I give it MAYBE a year.
That's a first!
)) However, "gone, never to return???" Don't count on it. I give it MAYBE a year.It was aluminum foil tape!!!
It was not duct tape but "aluminum foil" tape, used to join aluminum foil covered insulating material for home heat insulation. So far, the smell has not returned in more than 6 months, and I don’t expect it to return because of the low permeability of aluminum to methane and other gases. I promise to post it as soon as the stench comes back but, if it dears to do so, it will face a second coat of "aluminum" tape. An hour of taping per year beats a yearly replacing of the tubes. Plus, eventually, the total permeability of the increasing aluminum thickness will be enough to close the door on the stench. As always, thanks for your useful advice from a humble reader and admirer.
It was not duct tape but "aluminum foil" tape, used to join aluminum foil covered insulating material for home heat insulation. So far, the smell has not returned in more than 6 months, and I don’t expect it to return because of the low permeability of aluminum to methane and other gases. I promise to post it as soon as the stench comes back but, if it dears to do so, it will face a second coat of "aluminum" tape. An hour of taping per year beats a yearly replacing of the tubes. Plus, eventually, the total permeability of the increasing aluminum thickness will be enough to close the door on the stench. As always, thanks for your useful advice from a humble reader and admirer.
Hey
Gotta admit, this sounds kinda neat. A new solution to an old problem coming from a new source. I'll stay tuned.
Gotta admit, this sounds kinda neat. A new solution to an old problem coming from a new source. I'll stay tuned.
So will I, Chris...
I'll be especially interested in seeing what a combination of hydrogen sulfide, sulphur dioxide and other gasses do to the tape AND the hoses over time...I'll be asking questions of people who should know. Meanwhile, I wouldn't recommend that anyone else try it.
I'll be especially interested in seeing what a combination of hydrogen sulfide, sulphur dioxide and other gasses do to the tape AND the hoses over time...I'll be asking questions of people who should know. Meanwhile, I wouldn't recommend that anyone else try it.
One more advantage
Peggie, whatever the gases do to the tape will not be different to what they do to aluminum holding tanks that apparently do not fail by permeating. Electrolisis? My understanding is that for that to take place, you need an electrolite like salt water or peewe making contact between two different metals. In the case of the aluminum tape, it sits dry on top of a non-electrically conducting plastic tube and I do not cover any through hole hardware. Finally, and most importantly, because I don’t have to worry about the dreadful permeation, the tape has allowed me to modify your flushing algorithm to minimize water use. When you have a 10 Gal tank and 4 people onboard, two sittings per day per person will fill it in less than two days using the recommended 1 to 1.5 gal per flush. Since the tape was installed, I stopped being worried about permeation and I flush the head until all solids and brown water have been cleared. At that point, I add two cups of fresh water and a diluted amount of treatment fluid and I flush the head again followed by a last cup of fresh water. You see, instead of “pre-treating” the tank with the stuff, I dilute it and deliver it to the system in aliquots after each flush. In this way, most of the treating fluid remains in the tube until the next flush further minimizing the chance of permeation. Yes, I know that what I am writing here is sacrilege against your sanitation dogmas, but so far it has resulted in no odor an more than doubled the time between pumpouts.
Peggie, whatever the gases do to the tape will not be different to what they do to aluminum holding tanks that apparently do not fail by permeating. Electrolisis? My understanding is that for that to take place, you need an electrolite like salt water or peewe making contact between two different metals. In the case of the aluminum tape, it sits dry on top of a non-electrically conducting plastic tube and I do not cover any through hole hardware. Finally, and most importantly, because I don’t have to worry about the dreadful permeation, the tape has allowed me to modify your flushing algorithm to minimize water use. When you have a 10 Gal tank and 4 people onboard, two sittings per day per person will fill it in less than two days using the recommended 1 to 1.5 gal per flush. Since the tape was installed, I stopped being worried about permeation and I flush the head until all solids and brown water have been cleared. At that point, I add two cups of fresh water and a diluted amount of treatment fluid and I flush the head again followed by a last cup of fresh water. You see, instead of “pre-treating” the tank with the stuff, I dilute it and deliver it to the system in aliquots after each flush. In this way, most of the treating fluid remains in the tube until the next flush further minimizing the chance of permeation. Yes, I know that what I am writing here is sacrilege against your sanitation dogmas, but so far it has resulted in no odor an more than doubled the time between pumpouts.
Time will tell, Jose...
Get back to us in a year...better yet in 5 years. If all is still well then, you've hit on something. Meanwhile, I've already starting asking questions of people who can tell me whether you have, or only created a disaster in the making--and if so, why. Meanwhile I don't recomend that anyone else do anything to their own boat that only one person has done to one boat.
Get back to us in a year...better yet in 5 years. If all is still well then, you've hit on something. Meanwhile, I've already starting asking questions of people who can tell me whether you have, or only created a disaster in the making--and if so, why. Meanwhile I don't recomend that anyone else do anything to their own boat that only one person has done to one boat.
Verdict on aluminum foil is in.
Aluminum foil is an electrical conductor. If it comes in contact with ANYthing metal--a staple, a screw, metal pump housing, hose clamp, seacock...ANY metal...it becomes a conductor for electrolysis. You may think you have it isolated from contact with any metal, but there's no way to be 100% certain. If used in a system with an electric toilet or a Lectra/San, it's guaranteed to become "energized." If it gets damp--and what doesn't in a boat?--conductivity improves. As one of my sources put it, "A year or so down the road his prop, rudder or whatever could fall off from electrolysis-- and if his whatever falls off, he's in BIG trouble!" Sorry, Jose...but no way was this a good idea. All of the above is the reason no aluminum piping is ever used on a boat either. Saran Wrap is the only safe material that's also effective at blocking odor permeation.
Aluminum foil is an electrical conductor. If it comes in contact with ANYthing metal--a staple, a screw, metal pump housing, hose clamp, seacock...ANY metal...it becomes a conductor for electrolysis. You may think you have it isolated from contact with any metal, but there's no way to be 100% certain. If used in a system with an electric toilet or a Lectra/San, it's guaranteed to become "energized." If it gets damp--and what doesn't in a boat?--conductivity improves. As one of my sources put it, "A year or so down the road his prop, rudder or whatever could fall off from electrolysis-- and if his whatever falls off, he's in BIG trouble!" Sorry, Jose...but no way was this a good idea. All of the above is the reason no aluminum piping is ever used on a boat either. Saran Wrap is the only safe material that's also effective at blocking odor permeation.
Come on Peggy, I think A little Aluminum
on some rubber hoses is not going to cause ".... his prop, rudder or whatever could fall off....". I think statements like that cause false panic and are irresponsible. There is 'tons' on aluminium (and other metals) on a boat. Look at most masts, look at a lot of rub-rail materials, like someone said before, look at holding and water tanks. The list goes on and on ! Why brand new boats even use the sticky Aluminum foil tape he is talking about on alot of engine exhaust risers ! (Its on mine) (BTW the correct term is Galvanic corrosion, often misnamed "electrolysis," . It occurs when two (or more) dissimilar metals are brought into electrical contact under water. When a galvanic couple forms, one of the metals in the couple becomes the anode and corrodes faster than it would all by itself, while the other becomes the cathode and corrodes slower than it would alone. Electrolysis is the actual flow of electrons from this Galvanic corrosion and other things) As he said he was placing the aluminum tape to "sit dry on top of a non-electrically conducting plastic tube and I do not cover any through hole hardware. " So the most he would be connecting electrically (as a conductor) is one stainless steel hose clamp to another. Even if he was connecting more items it would be no worse that "bonding" your boat . Not only that, if it was a pure conductor metal to disimilar metal and it did cause galvanic corrosion (which is a very small chance in an isolated situation such as being in contact with rubber) it would be the Aluminum that would suffer the effects of galvanic corrosion. All types of Brass, all types of Bronze, Iron , steel and Stainless steel (propeller, props, rudders) are more noble than all types of aluminum (that includes the foil he was wrapping the rubber hoses with). So the most likely victim of galvanic corrosion would be the aluminum foil !!! (see the link posted below). The only problem I could see is that the aluminun foil would start to disinegrate from galvanic corrosion, it would become the sacrificial anode to everything but your zincs (and even that is to be seen on his boat in such an isolated environment) . (ps I make no claims to its effectiveness on odor to ones hoses or what it does to an Electra/San) BS Electrical Engineer '84
on some rubber hoses is not going to cause ".... his prop, rudder or whatever could fall off....". I think statements like that cause false panic and are irresponsible. There is 'tons' on aluminium (and other metals) on a boat. Look at most masts, look at a lot of rub-rail materials, like someone said before, look at holding and water tanks. The list goes on and on ! Why brand new boats even use the sticky Aluminum foil tape he is talking about on alot of engine exhaust risers ! (Its on mine) (BTW the correct term is Galvanic corrosion, often misnamed "electrolysis," . It occurs when two (or more) dissimilar metals are brought into electrical contact under water. When a galvanic couple forms, one of the metals in the couple becomes the anode and corrodes faster than it would all by itself, while the other becomes the cathode and corrodes slower than it would alone. Electrolysis is the actual flow of electrons from this Galvanic corrosion and other things) As he said he was placing the aluminum tape to "sit dry on top of a non-electrically conducting plastic tube and I do not cover any through hole hardware. " So the most he would be connecting electrically (as a conductor) is one stainless steel hose clamp to another. Even if he was connecting more items it would be no worse that "bonding" your boat . Not only that, if it was a pure conductor metal to disimilar metal and it did cause galvanic corrosion (which is a very small chance in an isolated situation such as being in contact with rubber) it would be the Aluminum that would suffer the effects of galvanic corrosion. All types of Brass, all types of Bronze, Iron , steel and Stainless steel (propeller, props, rudders) are more noble than all types of aluminum (that includes the foil he was wrapping the rubber hoses with). So the most likely victim of galvanic corrosion would be the aluminum foil !!! (see the link posted below). The only problem I could see is that the aluminun foil would start to disinegrate from galvanic corrosion, it would become the sacrificial anode to everything but your zincs (and even that is to be seen on his boat in such an isolated environment) . (ps I make no claims to its effectiveness on odor to ones hoses or what it does to an Electra/San) BS Electrical Engineer '84
Tom, I can only advise...
and pass on advice from other industry experts, which is what I've done here. Everyone I asked advised against wrapping sanitation hose in aluminum foil, because when dissimilar metals come in contact with each other, the result is galvanic corrosion and/or electrolysis. For that reason, even wire reinforced sanitation hose (not to be confused with hose reinforced with PLASTIC wire) shouldn't be used in sanitation systems that include an electric toilet, Lectra/San or other treatment device. But if you want to disregard that advice, it's fine with me. It is, after all, YOUR boat.
and pass on advice from other industry experts, which is what I've done here. Everyone I asked advised against wrapping sanitation hose in aluminum foil, because when dissimilar metals come in contact with each other, the result is galvanic corrosion and/or electrolysis. For that reason, even wire reinforced sanitation hose (not to be confused with hose reinforced with PLASTIC wire) shouldn't be used in sanitation systems that include an electric toilet, Lectra/San or other treatment device. But if you want to disregard that advice, it's fine with me. It is, after all, YOUR boat.
Yep...Saran Wrap
But ONLY the Saran Brand. Darned stuff is odor impermeable. Lasts about two years...at least that's how long it did on my own boat.
But ONLY the Saran Brand. Darned stuff is odor impermeable. Lasts about two years...at least that's how long it did on my own boat.
Saran did not work for me.
Tom, I could not agree more with you. Unfounded statements, and arguments such as “there must be something wrong with that because some body must have tried it already” are not helpful. The only reason I posted my finding was to help my fellow sailors save time and frustration in a lingering problem. I don’t know why but I seem to have touched a raw nerve here. There is no way that wrapping aluminum foil over plastic hoses could affect any metals electrically insulated from the foil. This is the same as saying that the using of metal clamps on plastic tubes would cause Galvanic corrosion and make your rudder fall!!! For “Electrolysis” to occur, you need to have an electrolyte in contact with both metals. This is why the sacrificial anode in a boat is placed in contact with the salt water and not onboard. Thus, even if I had covered the through holes or the clamps, as long as no salt water comes in contact with both the aluminum foil and the through hole, there is no reason for Galvanic corrosion to occur. But, if it ever did, as pointed out by Tom, it would be the aluminum tape and not the through hole the one to suffer. I have to add that before I used the aluminum foil I used the Saran brand saran wrap, covered with duct tape, and my head was stinking in less than a month. Although the plastic cover may delay the stench, eventually, it too becomes impregnated and begins to smell. The real advantage of aluminum foil is that it not only poses a very high diffusion barrier to the stinking gases, but it is a substance with extremely low solubility for those gases. I don’t expect that the permeation will ever occur, and as long as salt water, and urine are kept were they belong, the foil should last for a long-long time. Yes, Peggie, you could say that stray urine could reach the foil and serve as electrolyte. However, in my introduction to your Flushing 101 course, I point out to our guests that my wife has forbidden peeing in the standing position on our head (and at home too!!). In any case, because of hygiene and the stench it causes, we make sure that no urine is ever left on any surface. I do promise to report any unusual Galvanic corrosion in my boat as soon as it happens, but I am so confident that the physics are in our side, that I will keep my foil around the tubes. I also promise to provide yearly reports on the state of smell of our head. Finally, based on known physics, I believe that there is no risks of wrapping the tubes with aluminum foil tape as long as care is taken to avoid electrical connections with bare cables. If you are worried about electrical connections, you could always cover the tube aluminum foil with a layer of electrical tape. My solution not only eliminates the need to replace your permeated plastic tubes for expensive specialty tubes, that will permeate in time any way, but it allows you to decrease the amount of water used per flush, increasing the time between pumpouts. Anyway, no matter how much water I flush with, in my 361 there are two tubes, the sea discharge and the pumpout tube, that are always full of water with feces and, as predicted, those tubes rapidly permeated until they were covered with a metal barrier. Actually, the aluminum covered tubes look kind of nice and add a space shuttle look to our head Jose Venegas Ph.D. (Medical Engineering 83)
Tom, I could not agree more with you. Unfounded statements, and arguments such as “there must be something wrong with that because some body must have tried it already” are not helpful. The only reason I posted my finding was to help my fellow sailors save time and frustration in a lingering problem. I don’t know why but I seem to have touched a raw nerve here. There is no way that wrapping aluminum foil over plastic hoses could affect any metals electrically insulated from the foil. This is the same as saying that the using of metal clamps on plastic tubes would cause Galvanic corrosion and make your rudder fall!!! For “Electrolysis” to occur, you need to have an electrolyte in contact with both metals. This is why the sacrificial anode in a boat is placed in contact with the salt water and not onboard. Thus, even if I had covered the through holes or the clamps, as long as no salt water comes in contact with both the aluminum foil and the through hole, there is no reason for Galvanic corrosion to occur. But, if it ever did, as pointed out by Tom, it would be the aluminum tape and not the through hole the one to suffer. I have to add that before I used the aluminum foil I used the Saran brand saran wrap, covered with duct tape, and my head was stinking in less than a month. Although the plastic cover may delay the stench, eventually, it too becomes impregnated and begins to smell. The real advantage of aluminum foil is that it not only poses a very high diffusion barrier to the stinking gases, but it is a substance with extremely low solubility for those gases. I don’t expect that the permeation will ever occur, and as long as salt water, and urine are kept were they belong, the foil should last for a long-long time. Yes, Peggie, you could say that stray urine could reach the foil and serve as electrolyte. However, in my introduction to your Flushing 101 course, I point out to our guests that my wife has forbidden peeing in the standing position on our head (and at home too!!). In any case, because of hygiene and the stench it causes, we make sure that no urine is ever left on any surface. I do promise to report any unusual Galvanic corrosion in my boat as soon as it happens, but I am so confident that the physics are in our side, that I will keep my foil around the tubes. I also promise to provide yearly reports on the state of smell of our head. Finally, based on known physics, I believe that there is no risks of wrapping the tubes with aluminum foil tape as long as care is taken to avoid electrical connections with bare cables. If you are worried about electrical connections, you could always cover the tube aluminum foil with a layer of electrical tape. My solution not only eliminates the need to replace your permeated plastic tubes for expensive specialty tubes, that will permeate in time any way, but it allows you to decrease the amount of water used per flush, increasing the time between pumpouts. Anyway, no matter how much water I flush with, in my 361 there are two tubes, the sea discharge and the pumpout tube, that are always full of water with feces and, as predicted, those tubes rapidly permeated until they were covered with a metal barrier. Actually, the aluminum covered tubes look kind of nice and add a space shuttle look to our head Jose Venegas Ph.D. (Medical Engineering 83)
Gee Joe...
You are my hero. I'm going to get some aluminum tape right away. By the way, it is easy to "hit a nerve" in this forum. Everyone who posts becomes a target sooner or later. I appreciate your intelligent contributions as well as Tom's Chris
You are my hero. I'm going to get some aluminum tape right away. By the way, it is easy to "hit a nerve" in this forum. Everyone who posts becomes a target sooner or later. I appreciate your intelligent contributions as well as Tom's Chris
Aluminum tubes
I like the idea of the aluminum coverd tubes' "Space Shuttle" look. Can anyone quote the price of the "good," white sewage hose? The "price per wrapped hose foot" of the aluminum tape? Thanks, jv
I like the idea of the aluminum coverd tubes' "Space Shuttle" look. Can anyone quote the price of the "good," white sewage hose? The "price per wrapped hose foot" of the aluminum tape? Thanks, jv
It's cheap but price is not all.
John, I bought one roll of aluminum tape with one sticky side for less than $15 at HomeDepo. After covering all my tubes, I still have more than 3/4 of it left over for other projects. However, the real savings come from not having to take apart the stinking tubes to replace them. That for me was the major motivation.
John, I bought one roll of aluminum tape with one sticky side for less than $15 at HomeDepo. After covering all my tubes, I still have more than 3/4 of it left over for other projects. However, the real savings come from not having to take apart the stinking tubes to replace them. That for me was the major motivation.
Can't help with the alum tape.
John: Cannot help you with the tape cost but the White Odorsafe hose runs about $8/ft. The black Series 101 No-odor hose that west sells is about the same price. I have the black 101 hose in my Hunter that has been there for 8-10 years and there is no problem yet. When it starts to stink, I'll start to wrap with Alum. tape too.
John: Cannot help you with the tape cost but the White Odorsafe hose runs about $8/ft. The black Series 101 No-odor hose that west sells is about the same price. I have the black 101 hose in my Hunter that has been there for 8-10 years and there is no problem yet. When it starts to stink, I'll start to wrap with Alum. tape too.
Yep...hard pipe is not uncommon
And yes, hard PVC is odor-impermeable. However, because it doesn't bend at all, it's only advisable on larger boats that have long straight plumbing sections...otherwise, it becomes a collection of radius fittings and elbows, each one a "bump" that snares waste and paper. Because hard pipe should never be directly connected to anything fixed--toilet, seacock, macerator, tank--it's also necessary to use some hose...about a foot at each connection to act as a "shock absorber." Without some shock absorption, slamming around in heavy seas or even just a hard rap against a dock can lead to a cracked pipe...or worse yet, a cracked tank.
And yes, hard PVC is odor-impermeable. However, because it doesn't bend at all, it's only advisable on larger boats that have long straight plumbing sections...otherwise, it becomes a collection of radius fittings and elbows, each one a "bump" that snares waste and paper. Because hard pipe should never be directly connected to anything fixed--toilet, seacock, macerator, tank--it's also necessary to use some hose...about a foot at each connection to act as a "shock absorber." Without some shock absorption, slamming around in heavy seas or even just a hard rap against a dock can lead to a cracked pipe...or worse yet, a cracked tank.
I've only reported what experts have advised me
I didn't know whether it was a good idea or not...my expertise is plumbing, not corrosion or electrolysis. So I went to marine surveyors, sanitation equipment mfrs, and a friend who IS an expert in corrosion and electrolysis on boats. I didn't try to influence 'em in any way...I simply gave 'em the link to this thread, with the question: "This either a brilliant inspiration or a disaster in the making...which is it?" I waited till I heard from all of them before posting "The verdict is in..." Not one of them thought it was a good idea. And that's what I reported. And in reporting what they said, I've done my duty. . But Jose is defending it as if *I* were denying him a Constitutional right by doing so...Chris claims I've made Jose a "target." All I've done is ask experts and report what THEY say...by criticizing me, you're only shooting the messenger. What any of you choose to do to your own boats is up to you...all I can do is make it an informed choice.
I didn't know whether it was a good idea or not...my expertise is plumbing, not corrosion or electrolysis. So I went to marine surveyors, sanitation equipment mfrs, and a friend who IS an expert in corrosion and electrolysis on boats. I didn't try to influence 'em in any way...I simply gave 'em the link to this thread, with the question: "This either a brilliant inspiration or a disaster in the making...which is it?" I waited till I heard from all of them before posting "The verdict is in..." Not one of them thought it was a good idea. And that's what I reported. And in reporting what they said, I've done my duty. . But Jose is defending it as if *I* were denying him a Constitutional right by doing so...Chris claims I've made Jose a "target." All I've done is ask experts and report what THEY say...by criticizing me, you're only shooting the messenger. What any of you choose to do to your own boats is up to you...all I can do is make it an informed choice.
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