Holding Tank Vent Hose Replacement

[jolie]

My new 1996 Hunter 42 Passage had a smell that I finally traced to the holding tank vent hose. (Mistress once said wipe a rag on the hose, and if it smells the hose is permeated...) From this forum I learned about what happens when a hose gets saturated with that smell, and then its impossible to get rid of the smell.So I attempted to change the hose. But getting to the thru hull fittings was almost impossible. I read in this forum about access for my particular boat, through the forward starboard upper cabinet. I found the fittings, but for the life of me I couldnt reach the hose clamp enough to be able to be assured that I could put the new hose back on. ALSO, its important to note my boat has air conditioning, and that there is a wood column installed that allows the installation of an a/c duct that may be in the way of my gaining access, or the complete removal of a cabinet that looks like a lot more major than I am perhaps erver willing to do.So I cut 90 of the hose out and left just a 1 foot section that was already connected to the thru hull, and joined the new hoses to the old with a connector.The smell is gone, although leaving that last 1 foot of hose that I couldnt reach really bothers me. Enough to write to Hunter to find out how this happened, or is there something I am missing. I also had to use the existing connector to the holding tank bib. A tiny one inch connector...man did it smell! I soaked it in STRAIGHT BLEACH for 10 minutes and it didnt help AT ALL!!Also Hunter used a reinforced vinyl hose, where the reinforcement is a metal spring installed in the hose interior. What a dumb design selection for a hose that will ultimately trap smelly particles that accumulate during the OVERFLOW of waste that always invariably happens in a sailboat.OK its just a hose...but IT'S A HOSE THAT "MAYBE" CANNOT BE TOTALLY REPLACED...unless Hunter informs me I am wrong, to which I sincerely hope.Or MAYBE it takes alot smaller hands than I have to get in there to the thru hull fittings. And what happens when the thru hull fitting rusts?? Who's gonna change that?I am surprised at Hunter, but will let all know what happens.I have faith!PS: I also found the vented loop for the forward head, and with an electrically switched vent no less. Fancy...

 

[Peggie Hall/HeadMistress]

Hoo boy...

Well...at least now you've discovered first hand one of the reasons why bleach is useless as a cleaner. However, I've never recommended just wiping a rag on a hose to find out whether it's permeated. Unless you clean the outside of the hose first with detergent and water to remove any odor from another source that may have attached itself to the outside of the hose, you can be fooled into thinking that hose has permeated. After you've cleaned a small portion, wet a rag in hot water, wring it out, wrap it around the clean section and leave it till it's cooled. If the hose has permeated, the heat will transfer it to the rag...but if you can't smell anything on the rag, the hose is ok. So your vent hose MAY have been permeated..or it may just have been collected odor from another source. Since you couldn't replace one section of the hose, wrap it in Saran Wrap and secure the ends with electrical tape."...hose that will ultimately trap smelly particles that accumulate during theOVERFLOW of waste that always invariably happens in a sailboat." Although I agree that only sanitation hose should ever be used in any part of the system, the tank vent is not an overflow--it's especially not a substitute for a tank level indicator!--and waste should never be allowed to run out of it. To prevent heeling from causing a tank to overflow out the vent, the vent fitting on the tank should always be located closest to the centerline of the boat, not closest to the hull, and ideally on the top instead of on the end or side. As for access to the thru-hull fitting, that's a problem on many boats. And it won't be solved until the public is ready to accept a boat as a boat and not a floating condo. However, there are tools that allow you reach areas you can't get to with "standard" tools...you may have to invest in a couple of 'em.And as for the potential for the thru-hull to rust, I doubt if that's very likely to happen.

 

[john]

holdinbg tank vent

The vent on my 1991 P42 is cracked/broken - it's made of a light cast aluminum or something and it looks like someone tried to wedge a srewdriver in for some reason. Bottom line is that I tried to find a way to remove it and hit the same frustrations. Gave up and will sail with it broken until I get further enlightenment!But I think that there may also be a problem with the vent working properly, in that there's always backpressure in the holding tank after flushing. I removed the vent hose at the holding tank and pushed water out through it and then used a powerful vacuum to empty it (from inside the boat). Even after that, there is noticeable pressure in the holding tank, as evidenced by it bulging while flushing and contracting when emptying using the macerator pump. Any ideas?

 

[Peggie Hall/Head Mistress]

John, you need to correct the problem soon...

'Cuz all that flexing is gonna crack your tank if you don't. Even an especially strong pumpout pump could do it if the vent can't match the suction. To make sure it is the thru-hull, see what happens when you flush while the vent hose is disconnected from the tank. You cannot leave the vent hose off the tank till you can fix the problem, though...methane is flammable and must be vented to the outside of the boat. If the tank still flexes with the vent hose off, I'd replace the tank now--before it cracks--with a much thicker walled tank.

 

[jolie]

Vent line screen

I read that there was sometimes a screen in the vent line thru hull.Check and see if you a screen in there.You also can see the thru hull inside a removable wood partition in the forward starboard upper cabinet. Right?I get a slight vacuum too, and asked this group and the Head Mistress too.How do you see the tank swelling when on my boat its below the floor and surrounded with with foam?