Sealand / Dometic SaniPottie

[Fred]

we have the MSD 260 series (5 gallons). I don't know if the PO made modifications but the MSD pump out tube enters from the rear and slopes down to the front directly below the bowl discharge. Trouble is that toilet paper tends to hang up on this pipe preventing an effective gravity discharge. I often need to use an old screwdriver to move all the paper to one side or the other. The reason that I suspect that it may have been modified is that the tube inside the tank appears to be black (ABS?) whereas the fittings on back are white plastic. Does anyone else have some insight into this annoying problem.

 

[Peggie Hall HeadMistress]

I'm pretty sure you have a seriously modified portapotty...'cuz...
a) The 260 series is a Thetford model name...Dometic/SeaLand models are 964 and 965
b) there wasn't/isn't a MSD version of the 260... it was/is only made as a portable
c) the 260 tank isn't a 5 gallons tank, it's a 2.6 gal (hence the 260 model number)....and
d) MSD portapottie tanks aren't designed to drain via gravity.

That doesn't mean you don't have one which has a 5 gallon tank that drains via gravity...it just means that the PO created his own version of a 5 gal SeaLand MSD portapotty by swapping out the tank on Thetford 260 with a 5 gallon tank from a SeaLand MSD version and also modified that tank to drain via gravity.

So Fred...I'm thinkin' it just might be worth the effort and expense (minor) to replace it with a real 5 gallon MSD Portapotty. Both SeaLand and Thetford make one...the SeaLand is the 965MSD Sanipottie SaniPottie MSD and the Thetford is the 550P MSD. Theford Porta pottie 550P Both are available from the sbo.com online store for a very reasonable price.

 

[Fred]

My brain wasn't awake yet this morning. It is a 960 series.

 

[Fred]

The sealand unit offered at SBO looks like the same as mine

 

[Fred]

Maybe my terminology is incorrect... I use the term "Gravity discharge" to indicate that the bowl content simply drops into the holding tank (upon opening the slide valve). I believe that is the way most portable toilets work.

 

[Fred]

No replies on the interference of the dip tube and the "flushing" of the 960 series Sanipottie leads me to believe that a) nobody else has this problem and mine has somehow been modified or b) everyone is too busy sailing to worry about head problems. I'll have to locate and inspect a new unit to determine if there are any differences before replacing.

 

[twalker H260]

Fred. We have the same porta pottie. The diagonal tube centred under the gate valve is factory. I've seen it in both abs and pvc. Does occasionally collect a bit of paper during use but that is usually cleared by contents sloshing in the tank or during the next use. It's never really been an issue for us and I've never cleared the tube manually.

We usually have 4 on board.

 

[Fred]

Twalker...
Have you actually cruised with 4 or do you do day sailing? I find that after 1 or two days of cruising the content is a heavy sludge that does not "slosh" hence no longer displaces the accumulated paper. I try to discourage using too much flush water so that I can extend our cruise autonomy.

If this is standard design I might attempt a redesign that would curve th dip tube off to the side.

 

[Peggie Hall HeadMistress]

Fred, your problem is caused by too little flush water for anything to dissolve, even quick-dissolve TP (If that's not what you've been using, you need to start!), compounded by using too much of it. 'Cuz right now, sludge and TP are only blocking the pickup tube...re-routing it could very well let sludge and TP clog it and maybe even the pumpout line during pumpout. And the last thing you want to do is create an even worse problem by trying to solve one.

If you sail offshore beyond 3 miles where it's legal to dump a tank, you could put a y-valve in the pumpout line and run a line through a manual diaphragm pump (5 gallons would need about 4 pumpstrokes) to a thru-hull to do that. Otherwise, unless you want to spend about $1000 to replace your Sanipottie with an AirHead Airhead Toilet or Natures Head Nature's Head Composting Toilets, you'll just have to bite the bullet and start using a little more flush water.

 

[Fred]

Yes we have been using the expensive TP sold for portable toilets. We just came from a 3 week cruise (inland lakes) and we could not reliably achieve 4 days of automy with the 5 gal unit with 2 adults onboard. I carry a spare portapottie (2.5 gal) under my v-berth as a back up when we cannot make 4 days. Using more flush water will further reduce capacity.

Composting toilets are an interesting option but pricey for a problem that only arises 3 weeks out of the year.

 

[Peggie Hall HeadMistress]

Welll...let's do the math. The average adult uses the toilet 5x/24 hours, so in 4 days that would be 40 flushes for the two of you...your toilet should hold 50-60 flushes with normal flush water use. So it should easily last the two of you 5 days. So (just thinking out loud here )...When most things are dissolved in water their volume is reduced considerably, which leads me to wonder if not using enough flush water to dissolve the solids and TP could be the reason your tank isn't holding as many flushes as it should. Maybe someone who's more knowlegeable about hydro (aqua?) physics than I am will chime in here.

About TP: you don't have to pay the exhorbitant price for "marine/rv" TP. It's just the cheapest flimsiest TP you can buy at the grocery store, Sams or Costo for a LOT less repackaged and marked up. If you want to know whether any TP is suitable for use aboard, tear off a sheet and put it in a mason jar of water. Come back in a couple of hours and shake the jar. If the water is cloudy and all you see is a little "snow," it's the same thing as "marine/rv" TP...but if it's still an intact or mostly intact sheet, try another brand.

A few more words about TP: Most people use at least 5x as much as they really need (and TP is highly water absorbent, btw...which could be a contributor to your tank filling up faster than it should). Most seasoned cruisers have learned that only 4-5 sheets is enough to get the job done at least 90% of the time. I'll leave to y'all to work out the details of THAT learning curve! Just know that it's not that difficult to learn.

And that's about all I can contribute here...good luck, Fred!

 

[twalker H260]

Fred we do cruise. Myself, my wife and 12 and 15yr old girls. Depending on access to shore facilities, swimming etc we usually seem to manage about 3-4 days between pump outs. While we don't limit flush water or which operations are performed we do try to limit the amount of tp used, but when the kids were very little we had mixed success with this. As for type of tp used do Peggie's test. We generally use a bit better quality than the rev type as we seem to use less and it feels better but it still seems to dissolve quickly.

Our tank has never been so dry that the contents don't slosh about freely!

 

[Alan Gomes]

One thing you could try is the "Tijuana method" of depositing your toilet paper in a garbage bag next to the head rather than putting it in the head. (They do this in Mexico because of the "iffy" state of the plumbing.) Then you could use as much TP as you want.

I have an MSD porta potty with a 5.5 gal tank and I do this when I'm by myself on an extended trip. It makes a significant difference in capacity. I use a scented trash bag but it's really not a problem even using just a regular one. When my wife is aboard she's not too keen on the idea so then I just use the cheaper TP and don't worry about it. She's just turned off by the idea of it and so I've never done it with her aboard.

I think you should try this and see if solves your problem. While I realize it may not be the most appetizing solution, it's really not that bad and far better than carrying a spare porta potty, in my view.