will the 1" vent fix this?

[ereiss]

This is the second year with the new holding tank on our Freedom 38. The tank is under the v-berth. The vent runs under the berth forward to the anchor locker and exits out the side of the hull. The vent smell has been terrible. After trying several solutions (KO, using fresh water to pump) I did some searching and realized how small the vent is. On the exit size I can't even get a piece of my pinky finger into it. I would guess the vent is about 4-5 feet long.

So, before I replace the vent, am I overly optimistic in thinking this will eliminate the smell? There is nothing I can do about the length of the run, I don't think.

Two questions arise before I proceed.

1. What is the best way to increase the diameter of the existing through hull hole? Any secrets?

2. Is there a preferred vent line material?

Thank you for your assistance. The Admiral will be very happy when we don't have to be warned about an impending pump activity.

Ed Reiss
Being There
Freedom 38
out of Bristol, RI

 

[Peggie Hall HeadMistress]

A larger vent line will certainly help!

Where is the vent fitting on the tank? The vent line isn't too overly long...but unless it's at the bow end, we may need to move it to straighten it out AND make it bigger--which isn't a major big deal...in fact fairly easy, thanks to a li'l gadget called the UniSeal UNISEAL

As for the vent thru-hull...Fortunately it's a LOT easier to make a small hole bigger than it is to try to make a larger hole smaller...all you need is the right size hole saw. Also fortunately, the thru-hul is in the best location for a holding tank vent thru-hull...we just just to replace it with a plain ol' 1" bulkhead or "mushroom" thru-hull.

Use Shields or Trident #148 for the vent line.

All this would make a good winter project, and I'll be glad to help you with it. Meanwhile, use a screwdriver blade or whatever works to clean out anything that may be partially blocking the vent...also clean out the other end of the vent line and the vent fitting on the tank. THOROUGHLY rinse out the tank...and try using Odorlos (which RV supply stores have for a lot lower price than marine stores) in the tank, being sure to follow directions.

Btw...we ARE trying to solve an "odor out the vent line" problem here...NOT odor inside the boat...right?

 

[ereiss]

Vent line

Thank you Peggy.

The vent line is in the top center of the tank. And yes, it is a venting odor as we have learned to shut the hatches when we pump the head so that the cloud passes us by. All of the hoses were replaced when this new tank was put in so I firmly believe I have the problem identified and localized.

My Admiral is looking forward to my solving this problem so that her bloodhound nose can then search out the next irregular odor.

Thank you

Ed Reiss

Where is the vent fitting on the tank? The vent line isn't too overly long...but unless it's at the bow end, we may need to move it to straighten it out AND make it bigger--which isn't a major big deal...in fact fairly easy, thanks to a li'l gadget called the UniSeal UNISEAL

As for the vent thru-hull...Fortunately it's a LOT easier to make a small hole bigger than it is to try to make a larger hole smaller...all you need is the right size hole saw. Also fortunately, the thru-hul is in the best location for a holding tank vent thru-hull...we just just to replace it with a plain ol' 1" bulkhead or "mushroom" thru-hull.

Use Shields or Trident #148 for the vent line.

All this would make a good winter project, and I'll be glad to help you with it. Meanwhile, use a screwdriver blade or whatever works to clean out anything that may be partially blocking the vent...also clean out the other end of the vent line and the vent fitting on the tank. THOROUGHLY rinse out the tank...and try using Odorlos (which RV supply stores have for a lot lower price than marine stores) in the tank, being sure to follow directions.

Btw...we ARE trying to solve an "odor out the vent line" problem here...NOT odor inside the boat...right?

 

[Peggie Hall HeadMistress]

Sorry Bob, but I don't recommend vent line filters, especially on sailboats

For several reasons:

1. They actually help to create the problem they're sold to solve by impeding the free exchange of air needed to maintain the aerobic condition in the tank needed to prevent odors;

2. They are expensive...even your "bargain" version. Lifespan is only a year at most...toast immediately if they get wet.

3. Because sailboats heel, vent line filters on most boats WILL get wet due to waste in the tank spilling out the vent. If filters only ceased to trap odors when they get wet, it would only be an expensive solution that shouldn't be necessary if the system is correctly vented...but the charcoal swells up and completely blocks the vent, which causes REAL problems.

You said you tried everything, but I'll bet real money that your system can be vented to eliminate odor without the need for a filter.

 

[bobtigar]

1. A filter constructed properly, still allows for free exchange of air in and out of the tank. If you got a problem, why punch a bigger hole thru the hull when a simple solution exists. Rv's have the same kind of problem. Their stacks are usually 1 1/2". I determinded that my problem was that the vent line was very long.
2. This is an inexpensive solution compared with $20/qt chemicals and $2/ft hose. Refil the unit for about $2.00.
3. Put the filter high up in the line (by the outlet) and there is really a slim chance of overflow.
4. If it gets wet, whats the big deal...empty it out a refill.

Bob

 

[Steve Dion]

My question about vent filters is what happens when you "over-fill" your holding tank. It happens to us occasionally, but we have a straight thru hose.

 

[Stu Jackson]

Good point, Steve, but what many fail to also realize is that water can get in from the "outside" end, too! Like rain, or a rail in the water good grin-inducing sail. In both cases, the filters get wet.

 

[Steve Dion]

But Stu, I am more concerned about the "MATTER" that will plug the filter (yes? no?). I have never used one but "WET" may be the least of the issue.

I saw a friend with a 40ft + Carver open the deck fitting on his boat only to have the fountain of crap shoot up about 3 ft into the air. How do you explain that? <g>

 

[ereiss]

Connecting Vent to Tank

Peggie;

You said "unless it's at the bow end we may need to move it". I assumed that the vent need to be on the top surface as far forward as it can be rather than on a verticle surface at the bow end. I didn't want to misunderstand you comment.

As always, thank you for your wonderful help. Couldn't survive with you and your book.

Where is the vent fitting on the tank? The vent line isn't too overly long...but unless it's at the bow end, we may need to move it to straighten it out AND make it bigger--which isn't a major big deal...in fact fairly easy, thanks to a li'l gadget called the UniSeal UNISEAL

 

[Peggie Hall HeadMistress]

Yup...you understood it correctly

If possible, the vent should be on the top of the tank at the bow end. It may NOT be possible...'cuz that's gonna require a 1" elbow, which needs at least 3" clearance above the tank. In which case, we'll have to figure out the best place to put it on a vertical surface.

Does the tank lie along the hull...or does it sit on the centerline?

 

[ereiss]

Re: Yup...you understood it correctly

Peggie;

The tank is on the centerline, narrower toward the bow with little clearance under the berth. If I recall, and can check this weekend, there is an elbow where the vent comes out of the center of the access port. Can take some pics this weekend.

With all of your help how do I thank/compensate you? Your coaching and help is invaluable.

Best regards,