Installing a Composting Head on a Sailboat

Author:
Updated:
Original:
LQR_LidUp_White_36207_WhiteBack

When we bought our Allied Seabreeze sloop several years ago, the head and attendant systems were, at best, adequate. Nothing smelled, everything worked, but clearly we would have to upgrade at some point. Over the years, we replaced the sea toilet, went through several repair kits and researched options to upgrade the full system, including bladder tanks, gravity-emptying tanks, macerators and various pump types—like everything else on a sailboat, options were myriad, as were the opinions.

I had always been intrigued by the apparent simplicity of composting toilets and began to look at them in more detail a couple of years ago. While listening in at a vendor booth at a boat show, I ran into an experienced voyaging friend who pointed to the composting head in front of us and said, “Best thing we ever put on the boat once we got back to Maine.” A bit more research, some more opinions, and we settled on the Air Head composting unit. The system was simple, had undergone several years of improvements and would easily fit into our vintage 1960s head compartment.

Installing the liquid collection bottle on the head unit

Installing the liquid collection bottle on the head unit

Waste Not, Want Not

A composting toilet works by separating the solid and liquid waste. The solids mix with a moist, peat-like “medium” in the solids container, are periodically agitated and break down over time in an aerobic process (oxygen-rich). Keeping the solids dry (by separating the liquid waste) eliminates smells and accelerates the composting process. While the liquid waste must be emptied periodically (follow your local regulations), the solid waste container can last a cruising couple an entire season without emptying.
The first job was to remove the existing head system. Because we were already in the water, I elected to leave the seacocks and through-hulls in place. But everything else came off the boat … lots of hoses, valves, tanks and the porcelain throne itself. I felt better already!

Because the Air Head sat a bit taller than our flushing head, I had to build a new platform to establish the correct height for the seat. Some scrap ¾in plywood sufficed, and after patterning and cutting, I coated the new platform in epoxy and painted it a gloss white. After some fiddling with a dry fit, we were good to go. The unit installed with a couple of stainless steel brackets—simple enough.

Proper operation of the Air Head requires a positive vent system to pull air through the solids container and out to the atmosphere. This keeps odors and bugs from collecting, and provides a continuous source of oxygen. A 12-volt computer fan is provided as part of the system and is inserted into one of the two vent options (straight or 90 degrees). Siting this vent prompted the most head scratching, but I eventually settled on placing it directly on the cabintop, where I had just enough space to set it next to (and behind) a dorade vent. Some cutting work with the Dremel, a bit of caulking to install the Nicro vent, and that was done. The site needs some prettying up, but that’s this year’s project.

The brick for composting solid material (left) and the brick broken up and the stirring device that helps the solid material decompose (right)

The brick for composting solid material (left) and the brick broken up and the stirring device that helps the solid material decompose (right)

The fan needed a 12-volt source of electricity, so I wired up a small (10 watt) solar panel directly to the battery, located it on the cabintop under the boom (enough sun to do the job) and things were humming. Over the summer, we found that this small panel kept the battery fully charged against the demands of the exhaust fan.

To set up the head, I had earlier placed a “brick” of the provided “Coco Peat” into a garbage bag, added water and over the course of the installation day it expanded by absorbing the water. This mass of moist peat was placed into the solids container, mixed up with the self-contained agitator handle, and we were ready to go, literally.

When using the Air Head, liquids are diverted forward into a separate container (sitting is recommended, a small price to pay for males), and a “trap door” opens via a flip handle to accept solids and toilet paper. The liquid container fills up every couple of days and must be emptied. Keeping liquids out of the solids container is key to proper operation (and odor control), and despite initial doubts we found it quite easy to keep things headed to the right place. After making a solids deposit, a couple of turns of the agitator crank handle built in to the container is all that is required to keep thing working properly.

The author secures the liquid collection bottle to brackets (left); the finished installation of the new head (right)

The author secures the liquid collection bottle to brackets (left); the finished installation of the new head (right)

We use the boat a lot during the season, but with only two of us on board for much of that time we found that the solids container did not need emptying until the end of the season, and could have lasted longer. A boat with a larger crew, or liveaboards, will find the need for more frequent emptying. At the end of the season, I simply detached the lower solids container, attached the supplied lid, and after the recommended minimum three months of “processing” time to complete the composting (sitting in a corner of our garage), disposed of a season’s worth of “deposits.”

In a world of no-discharge zones, pump-out stations, smelly hoses, suspect seals and valves, and head horror stories (we’ve all got ‘em), we couldn’t be happier with our choice. Indeed, compost does happen, even on board an almost 50-year-old sailboat!

August 2015

Related

CONNECTING-SHROUD-2048

Experience: Wild Ride

My Hartley 38, Moet, is pounding into massive Pacific Ocean seas. One week of continuous storm conditions has taken me 700 miles south of Fiji, heading for New Zealand. Every few seconds the bow lifts out of the water and hangs in midair for a moment while I tense my muscles, ...read more

01-LEAD-nSterling-ProCombi-S-2

Know-how: Inverter, Charger Combos Offshore

With solid-state inverters and domestic AC devices becoming increasingly efficient, it only makes sense for many sailors to install the necessary 120V AC power for the many appliances now finding their way onboard: including washing machines, TVs, microwave, laptops, chargers ...read more

IMG_5308

Chartering in the British Virgin Islands

Not for nothing are the BVI known as the “nursery slopes” of sailing charters. There simply is no better place to ease yourself into a first-time sailing vacation; for that matter, such is the appeal of these islands that many charterers return year after year. The islands ...read more

IMG_7831

Racing and Bareboat Chartering in the BVI

If not all who wander are lost, then not all who charter are content with sailing between snorkeling spots and sinking a few Painkillers at beach bars. Some want a dose of hard-sailing action blended in with their sunshine and warmth—the kind of action you can only get from ...read more

01-GMR19FP45_1194

Boat Review: Fountaine Pajot Elba 45

With new catamaran brands springing up like mushrooms, France’s Fountaine Pajot is something of an oak tree in the market, with a story that goes back to its founding in 1976. It is also one of the largest cat builders out there, sending some 600 boats down the ways in 2018. The ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com Take no Chances This is my stern with the engine running slowly in gear against the lines. We all know that when we’re charging batteries this lets the engine warm up thoroughly. However, I have a ...read more

190910_ROSS_PORTSMOUTH_0187-2048x2048

Cup Boats Hit the Water

Emirates Team New Zealand may have been the first to launch a new-generation America’s Cup boat, but it was the New York Yacht Club’s challenger, American Magic, that had the last (first?) laugh. Just a few days after ETNZ’s radical-looking AC75 hit the water in mid-September, ...read more