When we bought our Super Maramu it came with two manual pump toilets and no
holding tanks. The first pump broke about two weeks in and we started thinking
about what we want to replace them with. All cruisers have stories about
blocked heads, broken pumps, stuck macerators and surprisingly quickly this
becomes a conversation topic. This article describes the first part in our
quest to reduce that pain and come up with a version that addresses at least
some of those, let's call them “interesting”, side effects of boat ownership.
Coming from a software development and sysadmin background I always think in
systems and failure modes. How will things break and what other systems can be
used to mitigate that. with that in mind I ruled out any of the electric
systems as I want my toilets to work even if we don't have power for any
reason. an Amel is a highly electric boat and we certainly do a lot to push
that way further than what is normal but funny enough with heads I feel like
that is a thing where we don't gain anything by having it electric.
Another topic is holding tanks. As ours has none adding holding tanks looked
not very appealing (something we may still do to the remaining toilet) so we
looked for alternatives. In our research we came across composting toilets and liked
the idea of having a holding tank that doesn't smell. Doing more research we
settled on the Airhead which is specifically designed for marine applications
and is super sturdy.
Removing the old head was simple enough. At the next haul out we can remove the
two sea cocks that were used for the old toilet and have two holes less in the
boat. Our SM is old enough to not have the central sea chest but individual sea
cocks, not many but closing some of them is always a reassuring thing.
Installing the Airhead is relatively simple. We built a small platform that can
fold away in front of the part that the original toilet sits on to have
something to rest the feet on when on the toilet. The Airhead is higher than
the original toilet and that little annex helps sitting comfortable.
The Airhead needs an air vent with a ventilator that runs all the time to blow
air across the compost and out the boat. This has the nice benefit of no smell
in the head, ever. I never had a toilet before that doesn't smell. The air vent
is ducted into a small charcoal filter and from there through the bulkhead
(near where the cables are pulled through) into the chamber that is above the
locker. That is the space the locker vents into and has the big round hole that
is normally not covered. There we have the small ventilator that pulls the air
and the charcoal filter helps that we don't have any smell in the cockpit.
In terms of maintenance, we have coconut husk that we bought cheap in
hydroponics stores so far. The liquid compartment needs to be emptied every few
days and the composting part about once a month. Both are pretty quick jobs,
just re-hydrating the coconut husk takes a few hours. We had issues with a
few flies once when the ventilator broke and having fly spray handy and putting
it into the composting bin a few times solved that pretty quickly.
We are super happy with the Airhead on our Super Maramu - happy to answer any
questions if anyone attempts a similar project.