Boat Plumbing – Part 3 – Out With The Old

October 2, 2018 Peter No comments exist

With the magnitude of challenges on the existing plumbing we made a decision to replace the existing toilet with a composting toilet. But first we would have to rip the existing system out. It would also be a good time to give the head a makeover. There were over 50 holes in the walls and it appeared that the plumbing had been moved several times and new holes drilled on each occasion. Given the amount of movement that happens in boats, the holes would have to be filled with epoxy and everything sanded before paint could be applied. The rotten wood in the passage next to the head would also have to be removed and replaced.


The head went from looking like this:

To looking like this:

Whilst we were at it, we painted the cupboards and gave the wood work a fresh coat of varnish.

The passage next to the head went from looking like this:

To looking like this:

Deciding on a composting toilet proved to be more complicated than originally anticipated. From the research we did, it appears that there are three composting toilets suitable to boats. The discussions on most boating forums center around these three toilets. They are, Nature’s Head Self-Contained Composting Toilet; Airhead Waterless Composting Toilet and C-Head Composting Toilet. Nature’s Head and Airhead have representation in Australia but C-Head do not. The Nature’s Head retails for A$1 540, the Airhead for A$1 690 and the C-Head for US$799 but it would cost an additional US$200 to have the C-Head sent to Australia and we could possibly also be in for import duty.


The Nature’s Head dealer happened to be on our way back from Surfer’s Paradise and we called in on them to have a look at the units. We were suitably impressed with the unit and the dealer was really helpful.

 For us there are a number of considerations:

  • Space is the major consideration. The area available in the head is fairly small. The smallest of the units is the C-Head but with no Australian representation we quickly discarded this as an option. The Airhead is slightly smaller than the Nature’s Head and also has the advantage of being able to be installed flush against a wall. The Nature’s Head requires a 50mm clearance at the back to lift the seat to remove the liquids container.
  • Both the Nature’s Head and the Airhead require ventilation and the manufacturers of both recommend a large hole be cut in the deck to mount the vent. We did however come across a blog post  of someone who built a composting toilet in a boat without a vent and a Youtube video of someone using a Nature’s Head in a RV without a fan and neither complained of any smell. We have a small vent on the deck for the black tank and, if possible, want to use this vent as the vent for the composting toilet. The only problem is the existing vent is less than half the size recommended by Nature’s Head and Airhead. We sent both companies emails and asked for their comments on our idea. The Airhead manufacturer felt that the idea wouldn’t work but the Nature’s Head distributor in Australia felt that, although not ideal, it would probably work. The problem is compounded by the fact that the fan for the Nature’s Head is mounted on the toilet (effectively pushing air out) but the fan for the Airhead is mounted on the deck (effectively pulling air out).

It is a catch-22 situation. We prefer the Nature’s Head due to the cost (they are both effectively doing exactly the same thing so the extra cost is not justified) and being able to use the existing vent, but it is slightly bigger and needs the clearance at the back to lift the seat to remove the liquids container. The Airhead is smaller and can be mounted flush against a wall but would require that we cut a large hole in the deck, something we are reluctant to do, and is more expensive. Every hole on the deck is just another potential problem and we have enough holes on the deck as it is.

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