Venting Composting Toilet To Anchor Locker

[cburger]

I am getting ready to install a composting toilet and it seems that Airhead suggests as an option the unit can be vented forward into the anchor locker rather than thru the cabintop. The anchor locker on my boat gets closed off with a couple of doors and even though tight fitting I am sure not airtight and am concerned about foul oder finding its way into the focsle.

Opinions about this appreciated.

[SailingHarmonie]

But a composting toilet does not smell, that's what everybody who has one says. What are you worried about?

[thinwater]

Originally Posted by SailingHarmonie

But a composting toilet does not smell, that's what everybody who has one says. What are you worried about?

LOL.


No, not terrible, but ....

[Cheyne]

We vented ours between the head wall and the hull where the old holding tank hose ran. Pry didn’t even need the hose since there is no smell from it. We have one at our cabin that isn’t vented except into the bathroom.

[John_Trusty]

Well the toilet on the inside doesn’t smell, but I’ve never put my nose up to the vent outlet outside the hull. The worst that will happen is you have a smelly foredeck. If you fail, you could reroute it next season to above the waterline at the bow with a clamshell vent.

[Mike OReilly]

I would be hesitant to do this, for the reason you are concerned about. No, these heads don't smell when properly used, but that's partly because they are vented externally.

I know some people don't bother with the vent, but I suspect that is mostly for the smaller versions, like the old C-head. These require more frequent emptying, so don't have a chance to build up any odours. Airhead, along with Nature's Head, are bigger. They typically go for about month between emptying.

As John says, you could try it, and if it fails you can always go the more standard route of direct venting. But unless it's a major PITA I would vent externally right off the bat.

[peghall]

I THINK he may mean that it can be vented out the hull through the anchor locker. I'll give him a call tomorrow to find out.


--Peggie

[kayakerChuck]

Following. I'm at this stage of my install.

[wrwakefield]

We put a Natures Head in our forward head. It is great with no odors inside, but I would strongly recommend against venting it into the anchor locker (or any other enclosed space) for several reasons:

1- You said your locker is accessible from the living quarters of your boat- so will be any odors and dust (read on)
2- There is lots of moisture in the vented air (these are really dessicating toilets...)
3- Sometimes there is fine dust exhausted via the vent hose while agitating- depending upon the media used (e.g., peat moss that is partially dry)
4- The moisture and dust will eventually coat everything in your locker, and is likely a great media for promoting mold and mildew
5- Short term odors while someone is using the head- before they agitate and close the lid. (That is another feature of these actively vented heads: odors during use are vented outdoors instead of the room the head is in...)

I recommend you vent directly to the outdoors (e.g., through the deck, etc.) to avoid creating new issues down the road...

FWIW

Cheers, Bill

[cburger]

All good points Bill, sold me

[cburger]

Originally Posted by peghall

I THINK he may mean that it can be vented out the hull through the anchor locker. I'll give him a call tomorrow to find out.


--Peggie

The reason for anchor locker venting is to reduce any chance of seawater breaking over stack and geting down into toilet. Venting thru deck at bow would negate this benefit.

[Mike OReilly]

Originally Posted by cburger

The reason for anchor locker venting is to reduce any chance of seawater breaking over stack and geting down into toilet. Venting thru deck at bow would negate this benefit.

This is the only major thing that has to me in about a decade of use. We got into some very large seas and I forgot to close my deck mushroom vent. Water did flood back down into the head. Turned the pile into a mess, and ruined the vent fan. Not a big deal to resolve, but still... a PITA.


Lesson learned... mushroom vent gets closed anytime conditions start to deteriorate. I'm also considering installing a simple valve inside the head compartment so it can more easily closed in the case of surprise weather.

Regardless, I still would not recommend venting to the anchor locker (but I take it you've already decided against this, so good ).

[wrwakefield]

Originally Posted by cburger

The reason for anchor locker venting is to reduce any chance of seawater breaking over stack and geting down into toilet. Venting thru deck at bow would negate this benefit.

When I first installed our Nature's Head, I connected the air exhaust hose to a solar vent. It keeps the water out, provides a secondary exhaust fan, and is closable when needed.

A future project is to repurpose the deck level pump-out fitting (since that holding tank is no longer in use...) with a closable mushroom vent. That will free up the solar vent to exhaust room air from that cabin.

Once I make the change to a muchroom vent, I need to safeguard against my forgetting to turn off the fan and close the mushroom vent before taking green water on deck.

My plan (not yet implimented) is to create a simple double P-trap. (P-traps are used under house sinks to prevent sewer odors from entering the house.

I will append an image of my rough concept sketch for reference in case it is of any use. (It simply represents my doodling of what we all already know and understand...)

Cheers, Bill

PS: Here is the link to the live document which may be changed over time, and will also contain product links that won't work in the attached image.


Note that the following sketch is live linked to the original, and will therefore update here if changes are made in the future.

[wrwakefield]

The illustration in my previous post, above, demonstrates the concept and flow of the water trap concept. Actual build- especially using flexible smooth bore bilge hose- could be quite compact.

Here is a more compact version of the water trap air vent concept which may have slightly less efficient air flow, but maybe not. And likely, that wouldn't matter much given the use case...

More FWIW in case it is useful to anyone, and in case it stimulates even better ideas and improvements from others.

Cheers, Bill