We now have our Air Head Composting Toilet installed and fully functional. We’ve had so many people ask us about our experience with installing and using a composting toilet on the Chesapeake Bay – literally dozens of people both at the marina and online – that I decided to make a thorough post about it.
We first saw marine composting toilets being offered at the 2010 Annapolis Sailboat Show, the two brands being the Nature’s Head and the Air Head. At the time, we weren’t in the market to buy either of them but I did take note and further researched both products. We had previously read very good reviews about composting toilets for remote cabins and off-the-grid living in general, but the marine products were new to us.
Once we purchased our Pearson 303 last spring, we had initially wanted to have a composting toilet installed by the boatyard we bought Shearwater from but were talked out of it before the refitting began. I don’t know if they weren’t familiar with composting toilets or really believed the urban myths surrounding them (smelly, don’t work well outside of the tropics, etc.), but either way we went with their recommendation instead – which was to have a new conventional head installed, since the one that came with Shearwater was non-functional.
That was the single worst decision we made in purchasing our good old boat.
The day we took ownership of Shearwater, we noticed a smelly funk that consistently got stronger the more we used the head during our long and hot voyage home. And the more the stench grew, the more we tried to get rid of it with all the means at our disposal. Long story short… we put up with the smell from July until the end of September, and every weekend we were aboard we tried to neutralize the smell using the latest advice we could obtain from others at the marina and via online sailing forums.
We finally decided that we were going to remove that miserable stinking head, the holding tank, the hoses and everything related to it. Then we were going to finally replace it with a composting toilet.
Period. End of story.
So… with pocketbook in hand, we went to the 2011 Annapolis Sailboat Show this past October with serious intent and a glint in our eyes. Both of the composting toilet brands were considered very carefully, with lots of close hands-on examination and questions being asked of the reps that were at the show.
|The Air Head display at the 2011 Annapolis Sailboat Show
|Air Head bowl|
|Air Head seat|
|Air Head lid seal|
|Air Head seat seal|
|Air Head solids container|
|Air Head solids operation|
|Air Head liquids design feature|
We went back to Shearwater that Thursday evening after the show to compare the measurements of the individual toilets to the space we actually had to work with aboard the boat, and to discuss which of the two composting toilets we both liked better.
In the end we went with the Air Head, though I expect both products will continue to leapfrog one another in features over time. For us, the Air Head appeared to have the edge in several design aspects, so that was the direction we went.
|Taking our new Air Head back on the boat show bus|
Once I got back to Shearwater with the Air Head in tow, I told Cindy we were removing the old head. Now. By ourselves.
Luckily for me, she was of the same mind and we jumped right into it. You can read my lengthy post about our experience with removing the old head here.
Once we got the old stench source removed, we still had other prep work to do before the Air Head could be installed and replacing the solar vent at the top of the cabin was at the head of the list.
What we had was a very old Nicro 4-inch passive solar-powered model without any provision for night use, which is specified in the instructions for the Air Head. Fortunately, Nicro offers a 4-inch passive solar-powered Day/Night Plus vent that operates 24/7/365 and has the same dimensions and installation screw locations as the old model, so it was a simple matter of removing the old vent and installing the new one using the exact same deck and screw holes.
|The new vent is on the left and the old vent is in the middle|
|After cleaning, the deck and core looks like it’s in good shape|
|Cindy’s view from below as I applied the new caulking|
|The new Nicro Day/Night Plus vent in place|
The new vent installed perfectly and instantly began to operate as soon as I switched it on, once I made my way back down below.
Now that we had the new vent installed, I focused on constructing a platform for the Air Head to be installed upon. Looking at the space we had to deal with (below), you can see that the existing fiberglass platform for the old head doesn’t have enough depth to it for the new one and will have to have something installed to lengthen it.
We had lots of discussion at this point as to what the final platform should look like, with no real consensus after a couple of hours of sketching designs and comparing viewpoints. With the end of the weekend fast approaching, we decided that a temporary wooden platform would suffice and we would use that as a pattern for the final solution.
One very important consideration for both of us was that we had to use only the pre-existing screw holes from the old head installation. Our rationale was that when we eventually sell Shearwater and upgrade to a bigger boat, the buyers of Shearwater may choose to go back to a conventional head and we didn’t want a lot of excess holes to hinder the resale value of the boat.
|Now to begin getting the head platform ready|
|Crafting the temporary platform|
I scampered down to the local Lowe’s home improvement center and brought back some pre-finished poplar board to use for the temporary platform. To craft it, I first had to make a pattern of the old holes and mark them in relation to where the Air Head needed to be placed.
If you look at the installed platform (below), you can see that we’re using the old installation holes – which are not centered in the platform board. The reason they are offset is that the Air Head needs room to the right side for the solids tank stirring handle.
|The temporary platform in place|
|With the Air Head in place – note the stirring handle on the right side|
|With the lid open to show final use configuration|
The Air Head does take up more usable leg room than the old conventional head did – quite a bit more, in fact. So much that we needed to rethink our final solution a number of times. As it was, the temporary platform was quickly found to be impractical; the Air Head has a high seat height and the temporary platform didn’t offer any foot rests for bracing when in the seated position. This isn’t so much of an issue when the boat is at the marina, but it’s a major issue when the boat is under sail and heeled at an angle while responding to the wave action.
However, while thinking some more about the final platform design, we decided to move forward with the flexible ventilation tubing connection from the solids tank to the overhead solar vent. One thing that we both kept pressing one another about was that the final Air Head installation needed to look like it was done by a professional and that included the platform, the connection to the overhead vent, all drilling, etc.
For the overhead vent mount on the underside of the cabin roof, I initially attempted to create a short wooden cylinder out of scrap wood from the boatyard. After a lot of attempts, I finally gave up; I couldn’t create what I wanted from scratch using a drill or jig saw, and I couldn’t find a large enough drill-mounted circle cutter to match the diameter that I needed.
|One of the failed wooden cylinder attempts|
|The core from one of the failed attempts|
What to do? What to do?
Over several weeks I kept trying to think of a vent mounting solution in terms of wood, preferably teak, because of the high amount of moisture we expected to have in the head area once we began to use the shower next season. Then Cindy finally said something about plumbing supplies and that got me to thinking about what was available at the local Lowe’s home improvement center.
So off I went. And after several hours of thinking, looking, measuring and sketching out ideas while strolling the aisles at Lowe’s, I came back with several PVC piping parts to craft what I figured would work.
|A 6-inch PVC pipe coupler|
|A PVC drain cover to be glued into the coupler|
|Once glued together, the excess height could be sawed off and sanded flush for a mounting surface|
|I discover that PVC is very brittle and has no shock strength|
After getting all the parts, prepping them and getting the PVC glue applied, I tried to assemble them together with a gentle tap of a rubber mallet… and everything broke. So back I went to Lowe’s to get replacement PVC parts, as well as additional parts to use specifically for the assembly.
|I found another PVC part that I could use for tapping instead|
|This worked like a charm and there was no damage on the second attempt|
|I just need to cut the excess height off and sand it flush with the grate surface|
|The inner wall needs to be removed, but doesn’t need to look pretty|
|Afterward, with all of the tools that I used|
Finally – about a month after we began the head replacement project – it was completed.
The overhead vent mount was finished and installed; the vent tubing was glued in place and functioning correctly; the temporary platform was removed and replaced with a new one made out of 1/2-inch thick Starboard marine-grade polymer; the new polymer platform had a vertical support leg installed (but not drilled into the cabin sole) and foot rests included; and – finally – the Air Head was charged with fresh coir, a compressed brick of ground up coconut husks that is crumbled apart and has water is added to it.
We have now been using the Air Head aboard Shearwater for over two months – in the winter. And with the temperatures dropping down into the mid-twenties at night. According to the urban myths, this is specifically the time of the year when these composting toilets aren’t supposed to work. Our Air Head has had substantial amounts of both liquids and solids processed through it and we can report that it works exactly as advertised.
There is absolutely no smell. None. Nada. Zip. Zilch. Our good old boat actually smells superior now than compared to when we first purchased it.
The installation upon the polymer platform is very solid and fully supports the weight of either of us without issue.
The solar overhead vent fan is acoustically isolated by the mount that I created out of PVC piping and cannot be heard, even in the dead of night.
We have had to dump the liquids tank once so far and that was performed without any issue, strain, drips, odors, smells or problems of any kind, either aboard the boat or when emptying the contents into the marina toilet.
The Air Head works perfectly for us and has completely eliminated everything we hated with the conventional head that originally came with the boat. We are not associated with Air Head and do not receive any compensation for this posting, but we highly recommend the Air Head Composting Toilet for anyone even remotely interested in trying one.