09 Sep Choosing Our Composting Toilet
One of our big “home improvement” projects has been to change from a traditional wet marine head to a Nature’s Head Composting Toilet (using this link gets you an automatic $25 off at checkout if you buy one).
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:
- Why did we choose to switch to a composting head?
- 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 accommodate 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 Head, Air 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.