Dometic 975MSD portable toilet

[WillieC]

We are, on the suggestion of the incomparable Peggie Hall, considering installing the subject porta-potty on the WillieC. The reason is that it will allegedly hold many more big jobs than our 13 gallon holding tank currently installed. Your mileage may vary.

It turns out that the holding tank can be the limiting factor when traveling into the hinterwater. Fuel we can carry extra jugs. Freshwater, same.

The subject named unit comes complete with a legit MSD hookup, making it easy to pump out if you are lucky enough to find a working pumpout station. Or, it can be disconnected from the evac hose and schlepped to a suitable landbased disposal system.

We'll figure out the details, but we are concerned about residual odors. We finally, under Peggie's patient tutelage, figured out how to make the boat with its original holding tank not stink. If changing to this unit stinks up das Boot...hmmm... Not so good.

The unit comes with its own vent fitting, as well as the pumpout attachment. It seems to me that the weak point could be whatever seal there is from the bowl to the 5 gallon tank below.

I would like to hear from those who have installed this or similar units on their A25 and how they are working, specifically, smelling. For less than $200 USD, this seems like a good idea.

[DesertAlbin736]

Well, you know about our holding tank story. One factor could be the height of the Dometic unit knowing how cramped the A25 head compartment is. I wouldn't think odor would be an issue. A lot of marinas don't allow dumping porta potty tanks into the restroom toilets. But yeah, you remember how hard it was to find pumpout facilities in BC if they ever let us in again. I've been happy with my 20 gallon tank, but that project opened up another whole cascade of expensive worms when it came to relocating batteries. We originally only had a 9 gallon tank which was even worse than a 13 gallon. What about going with a composting head?

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[WillieC]

I have pondered the composting head which should probably be called a dessicating head...hmm, new band name, The Dessicating Heads. Not a bad option in my opinion, but definitely requires some different thinking. I know some don't run a fan which would make me install some solar, yet another project.

If smell is not the issue, and your opinion doesn't count, DA, since the onset of your affliction...opening a box and shoehorning it into the head seems pretty simple. One owner totally simplified the pumpout by moving the deck fitting, very elegant. I am debating keeping the Y-valve and hand pump, at least until I am happy with the new set-up.

I suggested installing it in the aft cabin, next to West Maroon and Costco, but things are pretty jammed up in there. The Starfleet Commander wasn't too keen on the potential loss of privacy. Sheesh!

[DesertAlbin736]

I was thinking of head room, or sitting room as it were, above the toilet. If it wasn't for that stepped shelf it wouldn't be a problem.

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[WillieC]

I think headroom with the five gallon tank may be problematic, but I can deal with that. I am drooling over the extra space I could gain by losing the holding tank. Trouble is, that space is under the berth we usually leave made up. Maybe stuff more batteries down there.

[tribologist]

Are you planning to connect a Portapotty to a holding tank?

I ordered a B103 from Ronco plastic. It was by advice from Jim Orban. The Ronco fit in the space right behind the water tank and takes 20 gallon. It will sit higher than the toilet so maybe thats not an option? At least it will be lower than the seat but...

We have a Dometic 965 MSD in ours. Its only 2.6 gallon but takes us through a few days. THere are plenty pumpout opportunities here in NE. With two of the anti stink bags it does fine.


https://www.defender.com/product.jsp?id=435205

[WillieC]

The plan is to get the five gallon unit and connect it to the existing pumpout fitting, and its vent. We have a thirteen gallon holding tank, but what I understand is the Dometic (and other porta-pots) use so little water you can stuff a lot more flushes therein.

I think I ran across Peggie's suggestion in another forum. For small boats, she was all for it.
Edit: She says the 5-6 gallon pots can get 50-60 flushes.

We have a cheap boat toilet, the kit for which costs about as much as a new cheap toilet. If I can get considerably more flushes, manageable stink, and don't have to replace it every year...

DA went with a 20 gallon holding tank upgrade and that serves them well. We found out the 13 gallon unit in BC with rare pumpout facilities gave us cause for concern. Like the guy in the old commercial, "Five dollars for two quarters?!"

[DesertAlbin736]

DA went with a 20 gallon holding tank upgrade and that serves them well. We found out the 13 gallon unit in BC with rare pumpout facilities gave us cause for concern. Like the guy in the old commercial, "Five dollars for two quarters?!"

...and if we're offshore far enough to be legal we can drain the tank overboard. If we end up doing the Erie Canal & Chesapeake this year there appears to be sufficient numbers of pumpout locations. If we're careful, like me using a pee bottle to reduce number of flushes, ie waiting empty it into the toilet for when going #2, we can make it up to 5 days between pumpouts. The effective capacity is more like 15 gallons because the bottom won't drain the last inch below the drain/pumpout line (I try to fill & flush with fresh water several times at the pump out) and can't be filled above the inlet line at the top which means the last couple inches at the top are not usable. So15 gallons @ 4 qts per gallon & one qt per flush gives a max of about 60 flushes, or 40 flushes at 3 pints per flush. So 6 flushes per day using 3 pints of fluid per flush should last about 6 days between pumpouts.

Here was one pumpout locaton at Palmyra, NY, a little side cutout cove on the Erie Canal.

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