Sunday, April 19, 2020

Making a stable composting toilet base.

okay so we're really pretty happy with the new composting toilet build.  It works well and frankly looks nicer than any of the other versions of this design that we've played with. It's easier to dump and clean, and far simpler to route the urine diverter hose.  It's a keeper.

This one has worked out really well.
The only drawback is, of course, it's a bucket, and the sailboat moves.  We needed some way to anchor it securely to the cabin sole without making it difficult to remove and dump the waste.

We have, of course, done this before.  One of our first builds aboard Floating Empire was a similar bucket composter, but that one was without a urine diverter.  You can read about that build Here. if you're interested.

The method we finally fell upon to secure the head is a simple one: we use the bottom of yet another five gallon bucket to make a holder for the composting head.  It's pretty simple.  Wanna see?

Start by cutting off the bottom 6 or so inches of a bucket.
Begin by marking off the bottom five inches of another 5 gallon bucket.  The best way to do this is to lay the bucket on it's side and rotate it against a sharpie or something until you have an even line all the way around the base.  Then drill a starter hole and use a pvc cutting blade to cut the thing off.  Can you use a knife?  Yes, but it's hard to make the cut straight and, frankly, the chances of you cutting yourself are not insubstantial.

Here we go, the bottom five inches or so of the bucket.
Once you have that cut off, mark three relatively equidistant places along the rim and cut out three slots.  This you may need to use a blade for, because the jigsaw is kinda awkward.

This is pretty easy
You want something that looks like this.
The reason we're doing this is from horrible experience.  In our earlier build, we affixed the bottom foot or so of a bucket to the deck and dropped the composting bucket toilet into it.  It worked beautifully, keeping the john stable and stationary.  It was perfect. . . .

. . . until we went to dump it.  The polyethylene from which these things are made is slightly sticky, and the buckets had been pressed together repeatedly by . . .well. . .body weight.  When we went to dump the thing, it wouldn't budge.  Not an inch.  Not a freaking centimeter.  It was an airtight seal between the two of them and the air pressure didn't allow them to separate, which ordinarily wouldn't have been much of a problem, except one of the buckets was screwed to the freaking deck and the other one was full of . . .well. . .crap.  I wound up drilling holes into the base of the outer bucket to free it, and even then I very nearly collapsed the full bucket in the process. 

The cutouts are to allow air to get between the buckets and to allow some wiggle room to un-socket what is essentially your composter holding tank.

Check your placement, then just screw in place.
The new base holder can just be screwed to the deck with stainless screws and fender washers.  Then just drop the composter setup into it.  Voila!  You now have a slide proof, tip resistant john setup for boat or tiny home.

See the seam?  That's where they meet.
This has really been such a great version of our composting toilet, and with a total cost well under $50, it beats the living hell out of shelling out a grand for a commercial composter.  Nuff said.

As the weather has begun to cooperate a little, we've been using some of our time in Quarantine to do small projects and tidy up stuff, making ready for travel.  I installed grablines to the inside of the salon, which turned out well.

The new grablines.
If they look familiar, they're actually the underside of the identical grablines I installed on the top of the deck.

We just replaced the nuts holding these lifting bolts with ring nuts.  Took all of five minutes.
We're jonesing to get out on the water, waiting on the weather and to see what we can do during the Social Distancing.  I mean, what's more socially distanced than being anchored in the middle of the water?

Because nothing says Social Distancing like a few hundred yards of water.
Be sensible and safe, guys.  We'll all get through this if we just act like responsible adults.  Admittedly, I'm bad at that, but for all our sakes I'm willing to try.

More shortly,



  1. Love your new head!! Giving me ideas for one for my bedroom 🙂

  2. What about venting and agitation for the holding tank?

    1. Venting has never been an issue with any composting toilet we've ever had. Since there's no anaerobic decomposition, there's now smell of sewage. Frankly, we've never had one smell, not unless there was something amiss. This particular design has no inherent agitator. It would probably be more efficient and have to be emptied less often if it did, and there's certainly nothing to keep one from just plain taking a stick to it. Perhaps on subsequent versions we'll figure out an elegant way to do that, but for now, this seems to work great.