I had one of those installed at the factory when I purchased the boat.
It is a Thetford, 6+ gallon holding tank Porta-potti, with pumpout
and vent hoses installed in the usual fashion, except that the
'business end' goes through a special Thetford accessory fitting in
This gives me the convenience of pumpout, long times between those
pumpouts (PP's use a LOT less water than marine heads, so there is
about a 3-to-one advantage in holding capacity), and I can always
treat it like a normal PP if there is no pumpout available. BTW: It
is also fully legal in all of Canada.
It worked great for months, then began to stink really BADLY, then
began to leak. Let's just say I discovered that wastewater was
accumulating on top (yes - on top) of the lower unit of the PP and
'fermenting' until truly ripe, then treating us all to a truly
It took multiple (unpleasant) tries, but I finally figured it out.
The PP unit is large, and barely fits in the head while allowing the
door to close. This 'pushes' the hoses to one side at the back of the
unit. If you try to close (attach) the top unit onto the bottom WHILE
THE HOSES ARE 'PUSHED' to one side, the unit will 'click' shut, but
WILL NOT SEAL.
If you leave the lower unit unlocked (unsecured to the floor), AND
leave the hoses loose (rather than strapped to the back wall as they
are inclined to do at the factory), THEN close/attach the top, THE
UNIT WILL SEAL PROPERLY! At that point, you can 'push' the whole
thing into place, lock it to the floor, and it will continue to
I almost hate to admit it, but it took me three tries over several
weeks before I finally figured it out. At that point, I also
remembered that everything had worked fine until the first time I had
disconnected everything and dumped it like a normal PP rather than
just pumping it out as I had been doing.
Hope someone else can learn from this quicker than I did.
Are you certain you want to get rid of your Porta-potti in favor of a
built-in marine head? On Dynamic Equilibrium, we have a large Porta-
potti & stay with it for the following reasons:
1. I can move the Porta-potti out into the cockpit at night. This
way people hearing the call of nature at 2:00 AM don't stink up the
cabin or bother everybody else. If I'm sailing in Canadian waters, I
have brackets to secure the Porta-potti in place. I've been inspected
numerous times by Canadian authorities at Customs & never been cited.
Actually, I've never ever been questioned about the Porta-potti.
Nobody really expects to see a marine head with holding tank on a 22-
2. I am rigged up for either deck pumpout or I can take the Porta-
potti ashore for sewage disposal in either an onshore RV pumpout or
any gas station toilet.
3. Much less weight up in the bow when you compare the weight of the
Porta-potti vs. the marine toilet, associated plumbing, & holding
tank. The Rhodes 22 is sensitive to weight in the bow. Especially
if your boat wasn't originally designed for the built-in marine head,
be careful about adding a lot of pounds in the bow.
4. Wherever you put it, the holding tank will use up valuable storage
5. With judicious use of on-shore toilets, we find we can get a week
out of our Porta-potti. Are you really going somewhere that you
can't get to either a marine pumpout or some shore-based toilet for
longer than a week? Plenty of other consumable supplies like water
and ice run out long before the Porta-potti fills up.
Actually, I can only think of one positive reason for changing over
to a built-in marine head. It makes the boat seem more yacht-like as
opposed to more like a marine pop-top camper. If that's what floats
your boat; then, all of the logical arguments cited above don't mean
S/V Dynamic Equilibrium