Choosing Our Composting Toilet

By Carolyn Shearlock © 2015 • all rights reserved

Choosing a Composting Toilet: Why did we (A) choose a composting toilet and (B) choose the Nature's Head over others?

One of our big “home improvement” projects has been to change from a traditional wet marine head to a Nature’s Head Composting Toilet.

As we’ve been working on the project and I’ve been posting photos on The Boat Galley’s Facebook page, I keep getting two questions:

  1. Why did we choose to switch to a composting head?
  2. Out of the three brands available (and plenty of DIY plans available online), why’d we choose the Nature’s Head Composting Toilet?

So why did we decide to switch to a composting head? It was a big project, both in terms of work and money, so why’d we do it? In a nutshell, pump outs, stink and time spent repairing the system:

  • Small holding tank. Our holding tank, at 18 gallons, had to be pumped out every four days. That just didn’t work if we wanted to explore out of the way spots in the Florida Keys (you have to be 12 miles offshore in the Keys to discharge overboard). Those pump-outs aren’t free, either. While there is some cost to the composting medium, it is far less than what we were paying for “extra” pumpouts.
  • Stink, part 1. The holding tank vent on our boat was positioned so that noxious fumes went straight into the cockpit whenever the head was flushed. That meant that just getting a larger holding tank would not solve all of our problems.
  • Stink, part 2. There was a certain “head odor” inside the boat, too.  Not as bad as in the cockpit, but still noticeable. Replacing the hoses, which were a big culprit, would mean having to remove the holding tank because of where the fittings were. If we were going to have to remove the tank, we wanted it GONE. Composting heads, if built correctly to separate the solids and liquids, don’t smell. Period.
  • Clogs. Over time, we knew that salt water mixed with urine would cause deposits to build up in the hoses and then lead to clogs. Two problems: we have only one head, so an unusable head due to a clog is very unpleasant, and fixing the problem requires the hoses to be removed and either cleaned out (a very nasty job) or replaced. Again, removing the hoses from the holding tank is a very complicated procedure on this boat. There is nothing to clog up a composting toilet.
  • Repairs. Joker valves and pumps. It’s not fun to replace a joker valve or rebuild a head pump (yeah, the waste goes through the pump). The parts are expensive, too — over $50 a shot.  And when there is a problem, the head is unusable until the repairs are made. Not fun on a boat with only one head. In contrast, there is almost no way that a composting head can be rendered inoperable, particularly if you have a second pee container to use while the first is being emptied. And there is almost zero on-going maintenance (we try to keep the boat as low maintenance as possible so we have time for all the fun stuff cruising offers).
  • Fewer Thru-Hulls. With a composting head, we could get rid of two below-waterline thru-hulls: the intake for the head and the discharge line. Filling these in is optional in the conversion and took a lot of work (nasty with fiberglass and epoxy), added several weeks to the project (for us; you might be able to do it faster) and cost about $150 in materials alone. We thought it worthwhile from the safety aspect.
  • Lighter Weight. The composting medium and waste weighs maybe 10 pounds by the time it needs to be changed, compared to say 15 gallons of waste in the holding tank (at roughly 8 pounds per gallon, that’s 120 pounds), plus the weight of the holding tank and the sanitation hoses versus one lightweight ventilation hose. I’m guessing that we’re easily saving 125 pounds — and on a catamaran, every pound is precious!
  • Can Be Used on the Hard. Okay, this isn’t a major reason, but it’s sort of nice when we’re in the boat yard not to have to trek across the yard to go to the bathroom. Nice not to have go outside even though a thunderstorm is raging or having to get dressed in the middle of the night when “intestinal distress” strikes.

We decided to bite the bullet and deal with the hoses, holding tank and everything else once. The total cost of the project was about $1400, not including yard time (it could be done in the water if you don’t intend to fill in the thru-hulls). The cost will vary depending on the brand/model of composting head chosen, whether you remove and fill the through hulls, any remodeling needed where the head will sit, the vent chosen and what small bits of hardware and wiring are needed.

The time involved will also vary considerably by whether you decide to fill in the thru-hulls and whether anything must be remodeled in the bathroom to accomodate the composting toilet. Once the space was ready, it only took a day to do the actual installation.

So why the Nature’s Head? There are three popular brands of composting toilets for boats: Nature’s HeadAir Head and C-Head. All three are good, solid designs and people seem happy with whichever one they choose.

On some boats, only one brand composting head will fit, so this makes the selection simple. The measurements for each brand are different so if one won’t work, it’s likely that another will — and some are designed to be used in v-shaped bow locations or against a sloping hull. We did not have any special circumstances that limited our choice.

As we were researching, we very quickly decided against the Air Head due to the need to use a coffee filter for solid “deposits.” Some may not be bothered by this, but it just seemed weird to us. Further, several people have said that the coffee filters can get tangled with the agitator in the composting medium. It makes it hard to crank and then they have to be cleared — a nasty job that just goes against many of the reasons we want a composting toilet.

So that left us choosing between the C-Head and the Nature’s Head. The C-Head actually was originally designed for Gemini catamarans, so it seemed like the obvious choice.

But as we talked to friends that had either a C-Head or Nature’s Head, several who had chosen the Nature’s Head gave the same reason for choosing it: the 2.2 gallon urine tank. If you like to entertain aboard — having people over for drinks or dinner — you do not want an overflowing pee bottle in the middle of the party!

That made the decision simple for us. A secondary factor was that we both preferred the way that the Nature’s Head looks.

All that said, I think that we would have been happy with whatever brand we chose. Almost every person I’ve known with a composting head says it’s one of the best upgrades they’ve done . . . regardless of what brand they chose.

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Comments

  1. Great read Carolyn! Thank you for your insights.

  2. What do you do with the urine when at anchor inshore?

  3. Very interesting!

  4. Absolute agree with all you wrote! Used our NH just over two months and only did a partial empty when it got hard to crank. That’s full time use. YMMV. still no odor. 🙂

  5. Congrats on making the transition to a composting head! We did it last year, and I’m glad.

    We chose an Airhead because it was the only large-ish capacity one that would fit, but I’m sure we would have been happy had we chosen one of the competitors, instead.

    Although the air head instructions say to use a coffee filter, we don’t bother with it. I think maybe that’s to make clean-up easier if you miss the bomb-bay door when making a deposit. The coffee filter acts as a disposable toilet bowl liner.

    But, neither of us have ever “missed” because the bomb-bay door is positioned well. The only time we’ve used a coffee filter is when we’ve been ill.

    Also, if you choose to put a full dosage of toilet paper (or a coffee filter) into the composting bin with each use, consider adding some of the septic tank “helper bacteria” you can get in most hardware stores. If you toss in a tablespoon of this stuff every now and then, it seems to make the toilet paper (and presumably coffee filters, also) evolve into compost more quickly, and decrease the frequency of needing to change the composting medium.

  6. Something I would like to eventually do with my boat…but I wonder: Is it always legal to throw the pee overboard? Like, say, in Long Island Sound or other waters with lots of rules. I mean, if a guy peed off the bow, that would be ok…
    If you have to take the pee bottle to a land toilet to dump, that cuts down on how long you can stay out.
    A consideration for those of us who are not cruisers, just weekend drifters.

    • It all depends on the regulations. In a total “No Discharge Zone,” you can’t dump anything from any type of container into the water. But in many places, it IS okay for pee to go into the water. However, depending on the number of people aboard and the number of urine containers you have, you can go quite a few days before having to find a bathroom where you can dump it. And my experience is that it’s much easier to find a bathroom than a pumpout station!

  7. Edward Tordahl says:

    As I mentioned on another post, I had the Natures Head aboard my MacGregor 26X “LAIKA”. It was perfect for that boat. I loved it so much, when I sold LAIKA and purchased my Pearson 323, “SEA HAVEN”, I reinstalled the original Sanipotti, took the Natures Head and installed it on SEA HAVEN. Unfortunately now that SEA HAVEN is on the market, I cannot cost effectively reinstall the old holding system on her so I WILL be purchasing a new Natures head on the next boat!
    Composting is the way to go nowadays! Suffice to say a lifetime fan!

  8. Have been sitting on the sidelines looking at these for ages. Just curious though….how does the pee bottle cope with healing when sailing?

    • It will totally depend on the installation. Ours is fore-and-aft, and it appears that the boat would have to get to about a 90 degree angle before pee would start coming out (it’s a small opening in the top). If we get to a 90-degree angle (we have a catamaran), we’re going to have LOTS of problems and the pee bottle would be one of the smaller ones . . .

  9. We have also been contemplating switching to a composting head. One of my concerns is getting rid of the compost material when you need to. Do you just dump it in the trash bin?

  10. We went with a Nature’s Head also. A really good decision. Thanks for a very well thought out article that lays it all out for those in the research stage.

    Carolyn we hope to see you at the Annapolis Boat Show, will you be there?

    D & Don

    • Yep! Friday through Sunday — look for our t-shirts with the LARGE “The Boat Galley” on the back. I’ll be at the SAIL magazine booth from 2 to 4 on Saturday, and at the WWS get-together Saturday night.

  11. We installed a Nature’s Head at the beginning of this season and could not be happier with the outcome. You did a great job summing all the advantages with the conversion. I would add that removing the holding tank and all the hoses frees up a lot of space inside the boat. We essentially gained a whole new storage locker in the main cabin. We did encounter one small flaw in the Nature’s Head design that users should watch out for. The liquid’s trap is not completely separated from the solid’s port. It is possible for toilet paper to make its way into the liquid’s drain chute and block off the urine bottle. Liquids quickly travel to the solid’s container and there is little warning it is happening. Bad smells quickly transpired in our incident and the clean out was extra messy. If you don’t use coffee filters for solids (we don’t) then be vigilant in making sure nothing gets passed into the urine trough.

  12. Noreen Perryman says:

    Excellent feature tks Caroline. I have a few questions…1 Are these heads becoming cheaper with popularity or have you noticed price hikes as with our exchange rate they very expensive?
    Can you dispose of TP in the head or what do you do with #2 TP?
    Is it easy to find the ‘composting matetial’ ?
    Many thanks
    NP

    • I haven’t seen any change in prices in the past year. They say you can put small amounts of TP in the composting head; we don’t (didn’t with our previous head, either). We have a small lidded trash can that we put all TP in. You can almost always find some composting material — if nothing else, you can use sawdust. All depends on where you are, but just ask other cruisers who are already there and it’s very likely someone will have a composting toilet and know what’s available. And then the next week when someone else comes in and asks, you’re the one to pass the info on!

  13. One more composting head thought: if potential purchasers are concerned about the smaller capacity of the C-Head, know that the gallon milk jug urine container can be screw-capped, set aside, and replaced with another free gallon milk jug very quickly and easily. Discolored or scaley ones can be tossed out with nary a second thought. The full jug, if we are outside the 3-mile limit, (admittedly unlikely in our houseboat) gets emptied over the side every night, rinsed, and replaced. If we are in a harbor, we don’t even consider it, We tuck it into a shopping bag and tote it up to the shoreside toilet. One gallon is easier for this old lady to carry inconspicuously than 2.2 gallons! If we are anchored by a nice bit of accessible woodsy wilderness, we are assured that the plants up the hill a ways appreciate the nitrogen and moisture.

  14. we converted to a Nature’s Head several years ago in our Cal Cruising 36 sailboat and wouldn’t change back.

  15. I would love to hear your thoughts on the head now that you have had it for a while?

    • Nobody has talked about venting. At first, I planned to install a night and day solar vent for 24 hour venting. However, I decided not to because i did not want to cut a big hole in the boat for the vent and then build the adapters necessary to size down to the vent hose size. We settled on installing a wast tank pump out fitting which was the same size as the vent hose and had a screw in cap for sealing when away from the boat. I would attach pictures if I knew how! And, the small filler size allows for easily choosing a location.
      For air flow, we use the tiny wafer fan supplied with the Natures’s Head. It draws the tiniest amount of power so draw is not noticed at all. I recommend carrying a spare. A week point is that the wires for that fan are so delicate. I have adhered the fan into its cover with sealant so that the fan will not dangle by the wires when removing the housing to clean the dust filter. Power to this fan is the first breaker turned on when we arrive at the boat.
      We currently use compressed coir blocks and are happy with that. We bought a 10 pack of the smallest block available and this will probably last us 5 years since we are only on the boat 3-4 months at a time. We tried using peat early on, but I could usually only find bags which contained added fertilizer, etc, and usually only larger bags which were difficult to haul and took up much more storage.
      Following the rule of never depositing anything into the marine head which has not been chewed first, we do not drop toilet paper into the head. We use zip lock bags for toilet paper, recycling those which came with food in them, such as the bag tortillas come in. It is amazing how many zip style bags you end up with and they might as well be thrown away full of TP as not. Everyone finds a solution with which they are comfortable. That is ours.

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