Looking into composting toilet

[Mike OReilly]

nautical62, can you point us to the statute you've run into which make it illegal to dump into the municipal garbage system? The only restriction I've ever seen is the Annapolis marina which instituted a local harbour regulation (not a law).

As you point out, waste systems accept soiled diapers, and even used feminine hygiene products, both of which are worse than what comes out of a composting head.

I personally dislike using waste bins to dump my semi-composted material. Where, and how I cruise, means I rarely have to use that option. Most of the time I deposit my used material somewhere well off the beaten path in a wilderness anchorage. Or I dump when offshore, which again isn't hard to do for me.

I think in all the years I've had my composter, I've had to resort to a trash bin less than a 1/2 dozen times.

[Arion1234]

I installed a Sunmar GTG unit 12 months ago on my 25ft monohull. It is a slightly larger unit than models like the Airhead and has no agitator handle, just a vent to the deck with inbuilt exhaust fan in the back of the unit. You start with a couple of inches of mulch in the bottom of the solids chamber and add a handful more with each use. There is no odour below but a slight odour on deck near the vent, just an earthy whiff. Unfortunately, in an Australian summer, this does seem to attract a few more flies than usual in some anchorages (there are always flies here in summer). But the worst thing is that three times last summer they somehow got unto the unit. I have concluded they entered through two small holes, about 3/16", just below the fan chamber in the back of the unit. These holes, I assume, are to stop the exhaust fan creating a vacuum as it extracts air from the chamber. I am planning to discuss this with my supplier soon but my plan is to attach some flyscreen to the inside in that area with contact cement. Otherwise, I love having a no-discharge toilet. I am still experimenting with the type of composting agent and quantity. The supplier advertised sawdust but said they had none so sent sugarcane mulch. I might try peat moss next. I am also putting less mulch in after each use, so as to prolong emptying. If I could start again, I'd choose an Airhead or Nature's Head unit, as I have heard good things about these models.

[Fore and Aft]

I surveyed a yacht last month that had an "improved" composting toilet. They had plumbed the urine tank straight into the shower sump. That would have worked except the bilge pump in the sump had stopped working and it was quite some time before they noticed a bilge full of pee. Lets just say it was eye watering when I lifted the floor boards up! They had cleaned the bilge, but the pee had slopped everywhere so it was an impossible task to get it perfectly clean.
Cheers

[NorthCoastJoe]

I have an Airhead and happy with it. I got the one with the angled back so it fits against the hull nicely.

They make a pee bottle with a drain fitting on it. I thought about using that with a windshield washer pump to pump pee out above the waterline. If I ever make that setup I will let you know how it works out.

[Davy J]

Oh boy, another one of these threads......

Just checking in to say Natures Head, would not go back.........

[alctel]

Originally Posted by Mike OReilly

There are quite a few composting head threads on CF Bob. I've had a Nature's Head composter for approaching a decade now. I converted from a standard marine head with holding tank. My experience...

Pros:

• Removed the need to find pump out service. We are no longer limited by holding tank volume.
• Recovered significant storage space. In the space of all the hoses and holding tank I can now carry a couple of kayaks, more spare parts, and a sail.
• Significantly reduce complexity. Little can go wrong. No more dreaded blockages or backflows.
• Improved safety since no thru-hulls are needed.
• No ugly odours.

Cons:

• Urine jug requires frequent emptying; every two to three days for us (two adults, full time).
• Urine jug smells during dumping (no odour while in use). There are ways to reduce this.
• Dumping main bin requires you to be a bit more intimate with your outflows.
• Disposal of contents can be a challenge depending on location.

The biggest limitation (not really a con) is that these heads are designed for two to three people for full time use. Higher full-time numbers will overwhelm the system. It's not a problem to have more people for short periods, but they're really aimed at small crews for full time use.

You'll find that those of us who actually own and use composting heads tend to like them. Unfortunately, this topic seems to bring out a lot of inexperienced or uninformed opinion, so you'll probably hear from people who dislike them, and are not shy to say so.

This is a great summery.

I had a natures head on my boat, will install another one on my next boat.

[sesmith]

We have a C-head on our trailerable Seaward 25. Much better than the marine head it replaced. An added plus is that when we're hauling the boat we can camp out in it on the trailer and still use the head. We also put a C-head in our off grid cabin. It works great there, as well.

On our larger boat (Catalina 350) we have a Raritan Sea Era electric marine head. While I have a love-hate relationship with that one I like it well enough to keep it. I wouldn't hesitate to put a composting head in that boat if things don't work out with the existing setup, though.

[Erasmuss]

Originally Posted by Scorpius

We have an AirHead and are EXTREMELY pleased with it. It fit nicely in the tight space from which we removed the standard (Jabsco) marine head. We've never had a problem with it. As others have said, you have to remember to dump the urine container every few days. We also made another modification that has made it MUCH easier to deal with the solid waste. PM me for details.

I agree this must be " Super Bottom Secret " Information that is only available when transfered person to person within the " Cone of Silence "

Scorpius Come Clean with Your Waste Secrets !!

[Scorpius]

Originally Posted by Erasmuss

I agree this must be " Super Bottom Secret " Information that is only available when transfered person to person within the " Cone of Silence "

Scorpius Come Clean with Your Waste Secrets !!

Publicly? No.

[gauravshinde]

There’s a new product named compocloset that is smaller than airhead and naturesbasket. It’s going on sale I think. It seems like a great design. I have no connection, just a fan of good indiegogo tech.

I’m probably putting it on my boat as I want to reduce thru hulls. Biggest pro according to me.

Sailing Uma for a long time used a home depot bucket as their composting head and it seemed to work for them.

[SuW]

We installed a Nature's Head on our boat in 2010, after an unfortunate experience at the dock when the admiral (me) got sprayed with holding tank contents when trying to pump out. (Damn previous owner plumbing was as bad as his electrical work...)

We like it. Mike's analysis is absolutely spot on.

The only thing I'd add to the discussion is that we buy bricks of coir to use in the head. They are lightweight, compact, crumble easily and don't make as much mess as peat. Also probably more sustainable if that's important.

[Mike OReilly]

Originally Posted by SuW

The only thing I'd add to the discussion is that we buy bricks of coir to use in the head. They are lightweight, compact, crumble easily and don't make as much mess as peat. Also probably more sustainable if that's important.

I'll second the use of coir. This has been our bedding of choice for the past decade. It's cheap, easy to source, and comes in compressed bricks so it's easy to carry many months worth in a small area. And as SuW says, it's more environmentally friendly than peat in that it's an easily renewable resource.

When I start a new brick I put it in a large ziplock bag and pour in a bit of water (~couple of cups ...? I don't measure). Then I leave it in the sun for a while. After that it's pretty easy to break up.

I aim to keep the coir as dry as possible, while still allowing it to expand and be broken up. This means adding a lot less water than the directions usually call for to create standard plant bedding material (the usualy use for this stuff).

Is this what you do SuW?

[thinwater]

Originally Posted by SuW

...The only thing I'd add to the discussion is that we buy bricks of coir to use in the head. They are lightweight, compact, crumble easily and don't make as much mess as peat. Also probably more sustainable if that's important.

Maybe not.


I tested a bunch of absorbents for an up coming article, and coir was not the lowest odor (aspen pet bedding, local mill work sawdust, and fireplace ash were better). Since these are waste products, are locally available, and would otherwise go to the landfill, they are more sustainable. Coir is more compact (6:1 vs. 3:1), but there is also the hassle of re-hydrating coir, so I found aspen bet bedding more convenient for me. It is also what C-Head recommends. (Aspen pet bedding is indistinguishable from my local millwork shavings, except a very small amount of fine material has been removed and it is compacted.)



[Wood burning ash is the clear winner IMO for people that use wood heating (boat or home), but otherwise no. It can be a bit messy, but not with care. The trick seems to be that the high pH helps dehydrate the waste and suppress acid gases. More of a cabin trick than a boat trick.]

[piranha]

Using C-Head, no vent installed as suggested by manufacturer. Using cedar bedding for medium. Will never go back. Added baby carriage mosquito netting to avoid flies leaving eggs which happened a couple of times (gross). Been great ever since.

[SuW]

@Mike OReilly: Yep, pretty well the same. I put the coir block into a sealed plastic box with a cup or two of water and just leave it until I need it.

@thinwater: I defer to your expertise! I'd prefer not to use peat, obviously. I don't have a source of sawdust, or ash but I do have a source of ground up dried leaves, so that might be my next attempt, if we ever get back to the boat!

(We're locked out of the boatyard for Covid restrictions until the end of May, and Mike's locked out longer, afaik!)