Peggy, I have your book on Boat Odors and I remember it says that the holding tank vent should not be less than a 45 or 60 degree angle. There is a 90 degree elbow on my holding tank so the vent line runs FLAT over the holding tank for 1-1/2 feet and then curves straight up to vent out a stanchion. There is odor when the head is pumped. A few ideas I have are. 1. I could put a new vent hole in the side of the holding tank closer to where the vent line runs straight up but don't think this will help. 2. Another alternative that i don't like is to cut another through hull in the side of the boat. 3. I've also read about using an air pump to aerate inside the tank. 4. Install one of the vent odor eliminators. Please offer any suggestions as what is best to try first. Thanks Paul
Head Odor and Vent
- Thread starter Paul17656
- Start date
- Status
Head Odor
Paul: Does the odor occur after the boat has sat unused for awhile? Does it abate after several uses of the head? Is it stronger inside the boat, or outside? What are you using for odor control? We have a C36, and have this problem as well, but it does go away after several uses, and it is stronger outside the boat. I am currently using a product called Oderlos.
Paul: Does the odor occur after the boat has sat unused for awhile? Does it abate after several uses of the head? Is it stronger inside the boat, or outside? What are you using for odor control? We have a C36, and have this problem as well, but it does go away after several uses, and it is stronger outside the boat. I am currently using a product called Oderlos.
Head Odor
I tried using KO for about a year and just switched to SeaLand Secure. Odor is worse outside and does seem to improve after several uses but still not good. If the holding tank is emptied then it will be ok for about two weeks. I stay on the boat each weekend and ok for the first week but then empty the next weekend regardless of amount of use.
I tried using KO for about a year and just switched to SeaLand Secure. Odor is worse outside and does seem to improve after several uses but still not good. If the holding tank is emptied then it will be ok for about two weeks. I stay on the boat each weekend and ok for the first week but then empty the next weekend regardless of amount of use.
Odorloss
Assuming that your hoses are not a problem, I would suggest that you try Odorloss. It is a highly recommended product. Each and every time you pump your holding tank, I suggest the you flush out the vent too. Pump a gallon or two of water in the vent, then rinse the tank out with some additional fresh water. Then pump this out too. Once you pump out your holding tank, I would suggest that you add about 1/2 gal of fresh water and then pour in your Odorloss. This way it will be treating any remaining waste while you are away. We have been using it for a few years and have not had any problems.
Assuming that your hoses are not a problem, I would suggest that you try Odorloss. It is a highly recommended product. Each and every time you pump your holding tank, I suggest the you flush out the vent too. Pump a gallon or two of water in the vent, then rinse the tank out with some additional fresh water. Then pump this out too. Once you pump out your holding tank, I would suggest that you add about 1/2 gal of fresh water and then pour in your Odorloss. This way it will be treating any remaining waste while you are away. We have been using it for a few years and have not had any problems.
Are we talking about odor out the vent or
odor inside the boat? 'Cuz they're two entirely different issues...you can have both, or either...and you can cure one without curing the other. The holding tank, unless it's leaking, cannot be the source of odor inside the boat 'cuz odor from inside the tank only has one place to go--out the vent. So trying to get rid of odor inside the boat by treating the tank is a waste of effort. Odor inside the boat--especially if it's confined to the head--that only occurs after the boat has been sitting for a few days and goes away after the first few flushes is caused by stagnant sea water trapped in the head intake, pump and channel in the rim of the bowl. An all pervasive odor throughout the boat may have nothing to do with the sanitation system...a wet dirty bilge is a stagnant "swamp" that can smell like one, or even a sewer. So can a dirty sump, but the odor will most likely also be confined to the head because about the only place it can escape is out the shower drain. Permeated sanitation hoses are another source of odor inside the boat. Odor out the tank vent is caused by anaerobic conditions inside the tank. When organic material material breaks down without oxygen, it generates smelly sulfurouz gasses...but when it breaks down aerobically, it converts to CO2, which is odorless. So oxygen is the key to odor elimination in a holding tank...you want to prevent odor from happening in the first place, not try to "kill" it with chemicals after it's already occurred. That's done by increasing the diameter of the vent line to 1", and making it as short, straight, and as close to horizontal as possible. Sometimes two vent lines may be needed. Aerating the tank is an excellent way to eliminate odor...however, it shouldn't be necessary in tanks smaller than 30-40 gallons. Catalina makes it very hard to prevent odor because they run vent lines into rail stanchions, which make it impossible for the vent to provide any ventilation inside the tank--and barely provide enough air flow to keep the tank from pressurizing when the head is flushed and/or the pumpout from pulling a vacuum. Rerouting the vent line to an open thru-hull should help quite a bit. It's also important to follow the directions for use of any tank product. Odorlos is an excellent product, but often misused....just adding it once, or waiting till the tank starts to belch odor out the vent to add any more won't work. The tank should be treated immediately after pumpout, and then retreated at least once a week--more often in especially hot weather. Btw, Paul..."I have your book on Boat Odors and I remember it says that the holding tank vent should not be less than a 45 or 60 degree angle..." You need to read it again, 'cuz you have it backwards...the vent line should not rise MORE than 45 degrees off horizontal, not less. Any steeper than 45 degrees makes an exchange of air in the tank with the outside impossible.
odor inside the boat? 'Cuz they're two entirely different issues...you can have both, or either...and you can cure one without curing the other. The holding tank, unless it's leaking, cannot be the source of odor inside the boat 'cuz odor from inside the tank only has one place to go--out the vent. So trying to get rid of odor inside the boat by treating the tank is a waste of effort. Odor inside the boat--especially if it's confined to the head--that only occurs after the boat has been sitting for a few days and goes away after the first few flushes is caused by stagnant sea water trapped in the head intake, pump and channel in the rim of the bowl. An all pervasive odor throughout the boat may have nothing to do with the sanitation system...a wet dirty bilge is a stagnant "swamp" that can smell like one, or even a sewer. So can a dirty sump, but the odor will most likely also be confined to the head because about the only place it can escape is out the shower drain. Permeated sanitation hoses are another source of odor inside the boat. Odor out the tank vent is caused by anaerobic conditions inside the tank. When organic material material breaks down without oxygen, it generates smelly sulfurouz gasses...but when it breaks down aerobically, it converts to CO2, which is odorless. So oxygen is the key to odor elimination in a holding tank...you want to prevent odor from happening in the first place, not try to "kill" it with chemicals after it's already occurred. That's done by increasing the diameter of the vent line to 1", and making it as short, straight, and as close to horizontal as possible. Sometimes two vent lines may be needed. Aerating the tank is an excellent way to eliminate odor...however, it shouldn't be necessary in tanks smaller than 30-40 gallons. Catalina makes it very hard to prevent odor because they run vent lines into rail stanchions, which make it impossible for the vent to provide any ventilation inside the tank--and barely provide enough air flow to keep the tank from pressurizing when the head is flushed and/or the pumpout from pulling a vacuum. Rerouting the vent line to an open thru-hull should help quite a bit. It's also important to follow the directions for use of any tank product. Odorlos is an excellent product, but often misused....just adding it once, or waiting till the tank starts to belch odor out the vent to add any more won't work. The tank should be treated immediately after pumpout, and then retreated at least once a week--more often in especially hot weather. Btw, Paul..."I have your book on Boat Odors and I remember it says that the holding tank vent should not be less than a 45 or 60 degree angle..." You need to read it again, 'cuz you have it backwards...the vent line should not rise MORE than 45 degrees off horizontal, not less. Any steeper than 45 degrees makes an exchange of air in the tank with the outside impossible.
Holding Tank Vent
The odor definately comes from the vent and is stronger outside, it is inside only because the windows are open and the vent is on the upwind side in the slip. Odor only occurs when head is "pumped" and I've been using fresh water for the last two months. My description was incorrect. I do realize the vent needs to be horizontal and that a new thru-hull would need to be in the side of the hull. I'm not sure I like this idea. The alternative seems to be aerating the tank unless Ordorless works wonders.
The odor definately comes from the vent and is stronger outside, it is inside only because the windows are open and the vent is on the upwind side in the slip. Odor only occurs when head is "pumped" and I've been using fresh water for the last two months. My description was incorrect. I do realize the vent needs to be horizontal and that a new thru-hull would need to be in the side of the hull. I'm not sure I like this idea. The alternative seems to be aerating the tank unless Ordorless works wonders.
Flush Vent
I've not tried flushing the vent. Do you disconnect the vent hose from the tank and just run water into it with a hose?
I've not tried flushing the vent. Do you disconnect the vent hose from the tank and just run water into it with a hose?
Amazing Fortitude
Peggie Hall is incredible. I know of few people who would have the patience to re-write, for free, a book she's already written and gotten published, and then continue to try to help people who already have the darn book but can't "dig" what she's written. No knocks on Paul's well-intentioned question, but for goodness sakes, this stuff's been covered a million times. AND SHE STILL ANSWERS IT POLITELY. Stu PS Wish sometimes I could do the same. Guess I have a lot to learn from her. PPS Keep the questions coming, but please do some homework, after all, you already have the book, plus this search-able and archived website.
Peggie Hall is incredible. I know of few people who would have the patience to re-write, for free, a book she's already written and gotten published, and then continue to try to help people who already have the darn book but can't "dig" what she's written. No knocks on Paul's well-intentioned question, but for goodness sakes, this stuff's been covered a million times. AND SHE STILL ANSWERS IT POLITELY. Stu PS Wish sometimes I could do the same. Guess I have a lot to learn from her. PPS Keep the questions coming, but please do some homework, after all, you already have the book, plus this search-able and archived website.
- Status