Poop tank project

[Delta Riverat]

Is in full swing. Already installed the new level sensor so I now know how full the tank is. I also know that I have a vent problem. I know it works because it stinks when I flush, the vent outlet is right under a saloon window so when the windows are open in the summertime...everyone knows when you goes.

Have the DIY bubbler parts too and the circuit run for it installed when I did the sensor install. But wanted the sensor in before the bubbler as the air line into the tank is right in front of the sensor rod. But I also need a better vent.

Today I investigated the vents. They are clamshell type but only the covers on the outside of the hull. The venting to the outside is half inch copper pipe. So, next visit will be removing the 3 screw SS "clam covers" to see what is on the other side. In addition I have to pick the right one (the stinky one) as I have five of them lined up next to each other. So, I'm thinking 2 diesel, 2 water and 1 stink hole. Shouldn't be hard to identify and will be fun taking the screws out to see what I'm dealing with. When I have the right hole I'm sure I can replace the cover with a "mushroom" of some type.

The vent fitting out of the tank is a 3/4" MPT to half inch barb. This is the problem I'm sure. The inside of a half inch barb fitting must be what 3/8" No wonder I've been having pump out problems. The tank when full will have waste in this fitting which I've already verified. This will be replaced with a 3/4" MPT to 3/4" barb with 3/4" hose and connected properly to the existing outside vent hose.. Another thing I saw today was the half inch hose out the vent going straight into the hose leading to the hull vent. No adapter, just a hose stuck into another hose.

These old boats...

 

[HeadMistress]

I would "upgrade" the vent to 1" using a new vent fitting on the TOP of the tank that you'll create using a li'l gadget called the Uniseal UNISEAL . I'll walk you through the details. Vent line needs to be sanitation hose, which can be flexible PVC #148 (the cheapest sanitation hose). The thru-hull should be a bulkhead fitting, PVC or better yet, stainless steel.
Send me a PM ("conversation" in this forum) if you'd like to have my help.

--Peggie

 

[HeadedToTexas]

I am in the midst of this same project, though I'm temporarily hung up trying to remove the vent fitting in the hull. Perhaps this weekend...

 

[Delta Riverat]

There is much in favor of going to 1" hose and I verified that I could do it. Would need to put another hole in the hull big enough to pass the hose and the fitting through and use a starboard flange that I could screw to the hull. There is a good spot for it just aft of the port side engine room blower duct. There is no way to easily access the fitting from inside the boat but it would be easy to pass the tubing through from the outside.

Main benefit is it would relocate the stink hole from right under the galley/saloon windows and move it 2-3 feet away and below the deck. Really don't want to drill a big hole in the hull, but it appears the best solution.

 

[Delta Riverat]

The path is decided, going 1 inch. Ordered 25mm Dometic max flex and a SS 1 inch through hull. Not going to drill another hole in the tank, already has 3/4" MPT and I bought a 90 degree 3/4 MPT to 1 inch barb. I'll get 1/2" starboard from Tap Plastics in Stockton and get this puppy in. When that's done the bubbler will get installed. We'll be looking forward to a "not-so-smelly" summer of 25 -

 

[Delta Riverat]

Back to plan B. The path to the exit is not how I thought. The engine room blower ducts do not go straight out. They are ducted up along the saloon deck (engine room roof) and inner wall and then out the gunnels. The vents are half inch copper right tight up the inner wall.

And here are the 3 screw plates;

So, plan B is to simply replace the half inch "leader vent" off the tank with 3/4" and couple to the existing system. I'll ID the proper exit, clean it out and engineer a exit that I can back flush if needed.

Then on to the bubbler -

 

[dhays]

The bubbler will likely be the easiest thing you will do.

 

[Delta Riverat]

ID'd the tank vent today, it's the last one (closest to the steps) of the 5. Went down and cut the vent line and found the hose as I feared was 5/8" and my coupler didn't fit. But I also finished draining the water tanks and filled up with water through the softener.

The ID went smoother than I thought. I bought one of the little battery pumps with a needle to fill the fenders and I poked a hole in the vent hose and stuck the needle in and let it run. It had enough output to clearly ID the exit and wonder of it all, it didn't stink. Yeah a little but nothing like before. But the tank was finally sucked dry and I put in some percarbonate and some odor eliminator and it was much better than I was expecting.

Got a 5/8 to 5/8 barb coupler at the hardware store on the way home and will build up one side with tape and shrink wrap to fit the 3/4 tank hose.

 

[luna]

Got a 5/8 to 5/8 barb coupler at the hardware store on the way home and will build up one side with tape and shrink wrap to fit the 3/4 tank hose.

If I'm not mistaken Google will show that brass 3/4 to 5/8" barbed reducers are common & cheap.

These old boats.........

 

[Delta Riverat]

Thanks, just ordered one up. Still going to do the Jerry rig though until it arrives as the poop tank is now vented to the engine room. Good thing it's not summer time -

 

[t/t CVN69]

You are 100% certain that the vent fitting on the tank is clear correct? Recently dealt with this and while it looked clear on the hose end of the brass(*! #) elbow it was clogged and the tank end of the 90. GRP tank, old brass fitting came out and tabbed in a 1" exhaust elbow. New line and a new thru hull (that I put in the boot stripe after a loop we'll above the WL) and no problems 3 years later......

 

[Delta Riverat]

Yeah, I'm sure. I got air through it last visit when I ID'd the vent. The vent through hulls is half inch copper pipe and the hose connected is 5/8". The half inch line connected to the tank is going to 3/4" and there is now a 3/4 MPT 90 degree to 3/4" barb fitting in the tank where it used to be 3/4 x 1/2. Not ideal but much better than it used to be -

 

[DaveGibson]

Is in full swing. Already installed the new level sensor so I now know how full the tank is. I also know that I have a vent problem. I know it works because it stinks when I flush, the vent outlet is right under a saloon window so when the windows are open in the summertime...everyone knows when you goes.

Have the DIY bubbler parts too and the circuit run for it installed when I did the sensor install. But wanted the sensor in before the bubbler as the air line into the tank is right in front of the sensor rod. But I also need a better vent.

Today I investigated the vents. They are clamshell type but only the covers on the outside of the hull. The venting to the outside is half inch copper pipe. So, next visit will be removing the 3 screw SS "clam covers" to see what is on the other side. In addition I have to pick the right one (the stinky one) as I have five of them lined up next to each other. So, I'm thinking 2 diesel, 2 water and 1 stink hole. Shouldn't be hard to identify and will be fun taking the screws out to see what I'm dealing with. When I have the right hole I'm sure I can replace the cover with a "mushroom" of some type.

The vent fitting out of the tank is a 3/4" MPT to half inch barb. This is the problem I'm sure. The inside of a half inch barb fitting must be what 3/8" No wonder I've been having pump out problems. The tank when full will have waste in this fitting which I've already verified. This will be replaced with a 3/4" MPT to 3/4" barb with 3/4" hose and connected properly to the existing outside vent hose.. Another thing I saw today was the half inch hose out the vent going straight into the hose leading to the hull vent. No adapter, just a hose stuck into another hose.

These old boats...

That's an odd design. I'd leave the clamshell cover and run the vent line to the aft end where it belongs.

 

[Capt Ray]

Tangentially related info on this subject:

Clogged 1” sanitary hose from head to holding tank – solved!

Also worth mentioning:
We are NO LONGER happy with our SeaLevel II / Garnet tank monitor.
It might work again if I go in and scrub the inside of the holding tank!!! LOL
PITA
also: "Digester" chem products don't solve the problem. We've tried them all.

 

[Comodave]

Tangentially related info on this subject:

Clogged 1” sanitary hose from head to holding tank – solved!

Also worth mentioning:
We are NO LONGER happy with our SeaLevel II / Garnet tank monitor.
It might work again if I go in and scrub the inside of the holding tank!!! LOL
PITA
also: "Digester" chem products don't solve the problem. We've tried them all.

What material is the tank made out of? Non metallic and the Scad system will work. Simple installation and it is all external. I have put it in several boats and it worked flawlessly.

 

[Delta Riverat]

That's an odd design. I'd leave the clamshell cover and run the vent line to the aft end where it belongs.

Hehe, yeah baby! Got a chuckle out of that. Put the "anal vent" out the ass of the boat -

Maybe later after the bubbler project and after I get the new regulator hooked up and verify both alternators are working and find that the vent still smells bad when the heads are flushed.

 

[Bacchus]

That's an odd design. I'd leave the clamshell cover and run the vent line to the aft end where it belongs.

Optimum vent location can be different depending on situation & layout factors.
In my case we back into slip and spend a fair amount of time in the cockpit. My holding tank vent fitting is at fwd end of tank. I explored options for my stbd side vent and found few good ones... finally decided to install a DIY bubbler ( another topic but very pleased w outcome)
I finally figured a straight run was possible under the fwd bed to the bow area that already had the AC cooling water and anchor locker discharge. We rarely spend time at/near the bow, it's open to breezes from most prevailing directions and far away from any open port lights and neighboring boats. I'm very happy with vent at bow.

 

[Yachtman]

Is in full swing. Already installed the new level sensor so I now know how full the tank is. I also know that I have a vent problem. I know it works because it stinks when I flush, the vent outlet is right under a saloon window so when the windows are open in the summertime...everyone knows when you goes.

Have the DIY bubbler parts too and the circuit run for it installed when I did the sensor install. But wanted the sensor in before the bubbler as the air line into the tank is right in front of the sensor rod. But I also need a better vent.

Today I investigated the vents. They are clamshell type but only the covers on the outside of the hull. The venting to the outside is half inch copper pipe. So, next visit will be removing the 3 screw SS "clam covers" to see what is on the other side. In addition I have to pick the right one (the stinky one) as I have five of them lined up next to each other. So, I'm thinking 2 diesel, 2 water and 1 stink hole. Shouldn't be hard to identify and will be fun taking the screws out to see what I'm dealing with. When I have the right hole I'm sure I can replace the cover with a "mushroom" of some type.

The vent fitting out of the tank is a 3/4" MPT to half inch barb. This is the problem I'm sure. The inside of a half inch barb fitting must be what 3/8" No wonder I've been having pump out problems. The tank when full will have waste in this fitting which I've already verified. This will be replaced with a 3/4" MPT to 3/4" barb with 3/4" hose and connected properly to the existing outside vent hose.. Another thing I saw today was the half inch hose out the vent going straight into the hose leading to the hull vent. No adapter, just a hose stuck into another hose.

These old boats...

What material is the tank made out of? Non metallic and the Scad system will work. Simple installation and it is all external. I have put it in several boats and it worked flawlessly.

 

[Yachtman]

Interesting. A poop vent post and I’m learning new things that might help our similar issue.

 

[BrentwoodBayliner]

Question for the OP - can you share what kind of tank level sensor you chose and where to obtain it..? I'm just adding a new custom poly holding tank and looking at options.. ie: inside sensor vs. external sensor.

 

[Comodave]

Question for the OP - can you share what kind of tank level sensor you chose and where to obtain it..? I'm just adding a new custom poly holding tank and looking at options.. ie: inside sensor vs. external sensor.

If you are installing a plastic tank, preferably Ronko, and you don’t use an external sensor like Scad you will be making a mistake. And you will understand that the first time you have to work on the internal pickup. Ugh…

 

[Delta Riverat]

Question for the OP - can you share what kind of tank level sensor you chose and where to obtain it..? I'm just adding a new custom poly holding tank and looking at options.. ie: inside sensor vs. external sensor.

I used the rod style sensor and monitor from these New Providence Marine.

They do both types internal and external non contact but I have no access to sides of tank, only top and the sensor hole was already there.

 

[Bacchus]

If buying a custom tank I'd recommend adding a fitting to allow addition of a bubbler even if it's plugged initially. It can be from to or side/ bottom depending on your access. Better to have it... plug and never use it than want/ need it later and not have it.
I second Dave's recommendation for external sensors... they work very well and never need cleaning.

 

[HeadedToTexas]

I'll second (or third?) enthusiasm for the SCAD sensor. Non-contact, nothing to foul, easy installation, plenty of accuracy, and inexpensive. Definitely a win.

 

[OldDan1943]

Just my opinion, A choice between brass or bronze, go with bronze. If you a think a 90 will work, use 2X45, based on my experience on my N46.

 

[HeadMistress]

With the possible exception of a bell, brass has no place on boat. Bronze, chrome plated steel, PVC or marelon are good choices.

 

[HeadMistress]

Dave Gibson wrote: I'd leave the clamshell cover and run the vent line to the aft end where it belongs.

Very bad advice. Running a vent line out the transom only allows gasses to exit, preventing the air exchange necessary to prevent odor impossible and so does a clamshell cover.

Get rid of the "vent" thru-hull and replace it with an open bulkhead fitting. This has two advantages: allow the air exchange (oxygen) needed to create the aerobic environment in the tank necessary for the contents to generate odorless gasses and also prevent vent blockages by putting a nozzle against it to back flush the vent line on a regular basis. Anything attempting to set up house keeping in it will get a water slide ride into the tank.

--Peggie

 

[Delta Riverat]

The tank is no longer vented to the engine room -

Here is the tank in it's plywood box. The vent hose is the one in the middle, the infeed is on top where the slot is, the discharge is on the bottom right and that 1.5 inch MPT on the top right is where the bubbler hose will be fitted. See, no access to sides of tank, only the top. But, I'm ready to fit the bubbler -

 

[Delta Riverat]

I finished up the tank yesterday, put in the lid screws to secure the cover. Removed the clamshell cover from the vent hole and used a plumbing prep wire brush to clean up the copper.

Looks pretty good, they did a nice job of flushing the copper right to the wall. There was a lot of gunk in the pipe, couldn't even tell it was copper before I brushed it out. For a proper flange I got this brass drain adapter that I will glue a half inch copper coupler in and slide over the vent pipe, seal the connection with beeswax.

Not as good as a one inch all the way, but it's way better than it was before -

 

[Comodave]

If you have a bubbler system then the smaller diameter vent hose isn’t a problem as long as it doesn’t get plugged up.