Black water system renovation

[Steve.g.p]

We have a CS36T built in 1983. We are getting ready to replace the original black water tank and hoses because of odors in the bow v-berth where it is located. I am planning on cleaning and deodorizing the compartment where the tank is located (and surrounding areas). I was also considering painting the fiberglass surfaces in that compartment after cleaning before installing the new tank and hoses. Any input on this process and products to be used would be greatly appreciated.
Another question I have is, there are tanks with relief valves for high pressure pump out systems. If the tank is vented is this necessary and what tank manufacturer would you recommend? Again, thanks for your input. Steve

[peghall]

Unless a tank leaking it's rarely if ever the source of odor INSIDE the boat because odor from inside the tank has only one place to go: out the vent. So although it's entirely possible your odor is due to permeated hoses (replacement is the ONLY cure for that), it's unlikely that you'll need to replace the tank.

All waste holding tanks need to be vented...so you won't need any pressure relief valve...just learn to prevent vent blockages.

I suggest you check out the link in my signature for a lot more information about how to eliminate--and also prevent!--odors and how to maintain the system. And I'm always glad to answer any questions it doesn't.

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

[Steve.g.p]

Thanks Peggie, I was hoping to hear from you. I have a copy of your book about 'boat odors' and have referred to it many times. So you don't feel a tank can be permeated? If this is the case then I will think about continuing with the hoses first and cleaning / deodorizing the compartment area and see if I still have a problem. Any thoughts on the cleaning / deodorizing? I was thinking about water and bleach or "Odoban" (I think I have the name right) and having the mattress cleaned.
Thanks again for your help!
Seve

[peghall]

Any thoughts on the cleaning / deodorizing? I was thinking about water and bleach or "Odoban" (I think I have the name right) and having the mattress cleaned.

None of the above will help much. We need to discuss the whole project in more detail than is practical in a forum, so how 'bout sending me an email...that choice is directly above or below (I forget which) the PM option if you click on my name at the left of my posts.

Which version of my book do you have? The 2nd edition, released in Feb 2016 replaces a LOT of obsolete info and includes a lot that wasn't in the first one.

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

[somanyboats]

We had the same issue with our Santana. We were replacing all the toilet and plumbing with a composting system.
We cleaned the hull and painted with oil based primer, kilz or bullseye.
Then painted with an oil based enamel.
Thought that worked, but the smell was able to seep through.
Finally realized that the underside of the v-berth was raw wood and it had absorbed the sewage smell. Primered and painted it the same way. It mostly worked.
If I needed to do that again I would add a heavy dose of an essential oil to both the primer and paint.
good luck with it.

[Rick Williams]

I'm in the middle of that project right now. Our holding tank actually was leaking as I discovered after bleaching and deodorizing everything only to find the next week it still smelled.
My wife thinks the V berth is much more romantic so out came the old holding tank which was tiny (10 gallons).
We scrubbed everything and painted the entire holding tank area (it's not small) and all the surrounding nooks and crannies with a couple coats of Bilge cote which is great stuff but stinks. Needs good ventilation and lots of time to get hard.
We ordered a tank from Ronco, they've gotten rave reviews in this forum in the past and I'll add mine to the list. They were great! I sent a sketch of the holding tank space and Ronco sent me three different stock tanks that might fit.
I picked the one that was closest (36 gallons) and made a full size mockup (important step) out of cardboard and hot glue (3 hours in the garage) and walked it down the companionway and through the salon into the V berth to make sure it fit which it did but just barely.
I pulled all the hoses which I had replaced just a year ago and had to saw out some of the platform under the V berth to get the new tank in but at this point in the refit (rebuild) I'm pretty fearless with epoxy and repairs in general.
Ronco estimated a 3 week delivery so I'm making final adjustments including increasing the vent from 5/8" to 1" (better anaerobic) so the final install will go as smoothly as possible when the tank finally comes.
The tanks, BTW, are 3/8" roto molded polyethylene.
After that it's romantic V berth!

[a64pilot]

The 1” vent is an improvement.
I’d go so far as to even suggest that if the tank is somewhat centered in the bow area to put two 1”vents, on on the port side and the other on the starboard side.
I believe this would actually get some flow thru ventilation that would really help.

[Tillerjockey]

I just did this project this past winter. I too cleaned the area around the old tank but I didn't paint. The boat smells much better. No tank odor. Nothing too difficult about the project except that the new hose is very stiff and was difficult to bend in the small space under the sink in the head area. If you have a vent, no need to worry about the pump out.

[RSB333]

This project was on my winter repair list. After many hours of planning and building a mock-up tank of cardboard, my estimated cost exceeded the cost of a new AirHead composting toilet. Having good experience with a composting on our previous boat, I got rid of the holding tank, and now have another (clean) locker for storage.
RSB

[peghall]

After many hours of planning and building a mock-up tank of cardboard, my estimated cost exceeded the cost of a new AirHead composting toilet...

If you're happy with an AirHead, fine with me. However, I can't imagine who would have quoted you a tank price anywhere near the +/-$1000 price for an AirHead. Triple-M Plastics in Maine Triple M Plastic Products Inc could have made you a custom tank for +/- $500...and I'd bet real money you could have found a top quality rotomolded tank in the Ronco Plastics catalog (they have more than 400 shapes and sizes) Ronco Plastics marine Tanks for considerably less.

[Sherrill]

I’m in the process of specifying a new 30 gal holding tank (PE or HDPE) for a ‘under v-berth’ location. Given the tight clearance at the top of the tank, I will probably need to use the low profile, 90° tank to hose fittings available, for inlet, and vents, and possibly the dip tube

Firstly. Any clear winner - for odor or splash leakage or serviceability - between the various options for tank inlet and vent connections?
1) FPT, drilled and taped (extra backing)
2) FPT, from spin weld fittings (might just be able to fit a protruding MPT fitting if less than 1” height)
3) Cleanly drilled hole, for use with a ‘grommet’ and tightly mated pipe (like uniseal or similar)
4) Cleanly drilled hole for use with a reverse threaded ‘bulkhead’ fitting, single or double gasket (many options to connect, like NPT, or pvc slip/spigot.)

Secondly:
Has any one experienced problems with using a dip tube, and is there a preferred commercial or DIY design and fitting type that seems to work well for a dip tube? Any issues with tank contents putting stress on a dip tube or its fitting, as it sloshes about. Does the tube need to be anchored inside the tank by some mechanism?

Thirdly.
Do holding tanks need an access port? If yes, what size/manufacturer recommended? Seems like just another opportunity for leakage/odors.

Thanks for any insights…

[Peregrine1983]

Just completed the same project. As far as removing odors from wood and the surrounding boat, nothing worked as well as this stuff diluted in a spray bottle:

Angry Orange Pet Odor Eliminator 8 oz. bottle- Industrial Strength Pet Odor Remover

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[fatherchronica]

It is my experience that if the tank is not leaking that the permeation of stank is from non-compliant hoses. Also a recent innovation of Blackwater is to change it's name to Xe and build a secret private army base in Western China. That information also came from a smelly leak.

[Delfin]

If you wrap replacement hoses with Petrotape, it extends their life, stink wise, by many, many years.