Installing a MSD potty in our C22

[Sail22Capri22]

I mimicked @AaronD almost exactly (again thank you Aaron for the write up) for my install and am very happy with it. I went with the Vetus 5/8" vent part# AB16B that Aaron had installed also. I was going to do a thru hull fitting as recommended by Peggie but was still uneasy with water getting in the toilet when the boat healed and waves moving over the side of the hull. My thinking is that the Vetus vent will slow some of the sea water getting in there. Also the Vetus vent has two Philips head screws to remove the cap on it so it can easily be cleaned and blown out IMO.

 

[AaronD]

I assume you went out through the hull with your vent, as opposed to out through the deck?

Correct. Just below the rub rail. Pictures at Sailing and restoring #9874

In your thread you mention "Sani-Fresh" hose, I assume you meant Sani-Flex? @Peggie Hall HeadMistress has endorsed Sani-Flex as her favorite, so that's what I ordered earlier today. Well, her endorsement and the fact it is supposedly the most flexible, which I think is going to be important. There was a little sticker shock when I saw my total with tax and shipping. The best price I could find was $16.80/foot at Fisheries Supply.

Yes; sorry for the typo. I'll edit my original post and correct that. I paid ~$13/ft a few years ago, so $17 isn't surprising.

 

[Peggie Hall HeadMistress]

Defender's price is much better. They're on the other side of the country from you in CT, but I have read that they have free shipping on $100+ orders . Worth checking out.

--Peggie

 

[Gene Neill]

The hold down bracket is taking shape. I had this 12"x12" sheet of 1/4" G10 fiberglass on hand, so that's what I'm using. It'll be just a basic sort of 'Z' shape, with right angles, and extra bracing at the base. Hopefully it's bomb proof. I don't wanna build it twice.

 

[Gene Neill]

There is precious little info out there about plumbing porta potties. Very few are plumbed at all, and fewer still have overboard discharge capability. Even the instructions that come with the Thetford 550P MSD make no mention of plumbing at all.

My original intent was to use a manual waste pump, plumbed between a lockable Y valve and a through hull. But this type of toilet can leave solid waste pretty solid, for a pretty long time, presumably since the solids don't pass through any kind of a pump on their way to the holding tank.

So. Should I consider an electric macerator pump?

 

[Alan Gomes]

There is precious little info out there about plumbing porta potties. Very few are plumbed at all, and fewer still have overboard discharge capability. Even the instructions that come with the Thetford 550P MSD make no mention of plumbing at all.

My original intent was to use a manual waste pump, plumbed between a lockable Y valve and a through hull. But this type of toilet can leave solid waste pretty solid, for a pretty long time, presumably since the solids don't pass through any kind of a pump on their way to the holding tank.

So. Should I consider an electric macerator pump?

I have mine plumbed through a macerator and then to a through hull for overboard discharge when 3 miles out. Although I do have a deck fitting for a deck pump out, I do not have it currently plumbed for that, since going 3 miles offshore is trivial and something I do on all of my trips where the porta potty gets used anyway. Hooking it up to the deck fitting would be an easy matter of setting up a Y connection to the discharge hose. No biggie.

I use Noflex Digester and it makes short work of any solids in the tank. In the past I used Odorlos, but that did not take care of the sludge. The Noflex product does a fabulous job and leaves the porta potty free of any solidified or calcified materials.

At the end of each trip, I am also careful to rinse the Porta potty with multiple buckets of seawater, again while I am 3 miles offshore. Then, when I am back at the dock, I add a gallon or so a freshwater from a bucket and a small amount of Noflex Digester. No problem with odor or sludge.

 

[dlochner]

I have mine plumbed through a macerator and then to a through hull for overboard discharge when 3 miles out. Although I do have a deck fitting for a deck pump out, I do not have it currently plumbed for that, since going 3 miles offshore is trivial and something I do on all of my trips where the porta potty gets used anyway. Hooking it up to the deck fitting would be an easy matter of setting up a Y connection to the discharge hose. No biggie.

I use Noflex Digester and it makes short work of any solids in the tank. In the past I used Odorlos, but that did not take care of the sludge. The Noflex product does a fabulous job and leaves the porta potty free of any solidified or calcified materials.

At the end of each trip, I am also careful to rinse the Porta potty with multiple buckets of seawater, again while I am 3 miles offshore. Then, when I am back at the dock, I add a gallon or so a freshwater from a bucket and a small amount of Noflex Digester. No problem with odor or sludge.

A more affordable and equally effective alternative to NoFlex Digester is Camco TST (Amazon Link). It comes in a variety of flavors and does a great job of breaking down TP and solids.

 

[Peggie Hall HeadMistress]

There is precious little info out there about plumbing porta potties. Very few are plumbed at all, and fewer still have overboard discharge capability. Even the instructions that come with the Thetford 550P MSD make no mention of plumbing at all.

Only MSD (fitted for pumpout) portapotties are intended to have any plumbing and that only consists of a tank vent and pumpout line....How much instruction do you need to connect two hoses? They're not meant to be discharged overboard, but that's easy to do too: put a y-valve in the pumpout line and run hose to a macerator or manual diaphragm pump and thru-hull.

--Peggie

 

[Peggie Hall HeadMistress]

A more affordable and equally effective alternative to NoFlex Digester is Camco TST (Amazon Link). It comes in a variety of flavors and does a great job of breaking down TP and solids.

Does it also dissolve sludge? No-Flex does. And what about odor prevention? RV tanks vent out the roof of the coach, so while it may reduce or even eliminate odor in the head, odor out the vent isn't an issue for RVs.

--Peggie

 

[Gene Neill]

: put a y-valve in the pumpout line and run hose to a macerator or manual diaphragm pump and thru-hull.

--Peggie

No vented loop necessary?

Is a seacock recommended for redundancy, or can the Y valve be depended upon? The holding tank is roughly split in half by the waterline.

Thank you Peggy!

 

[dlochner]

Does it also dissolve sludge? No-Flex does. And what about odor prevention? RV tanks vent out the roof of the coach, so while it may reduce or even eliminate odor in the head, odor out the vent isn't an issue for RVs.

--Peggie

Peggie, I don't have much if any of a sludge problem. The two products are essentially the same. The active ingredient both is
Sodium Carbonate Peroxyhydrate. TST adds salt, Noflex adds sodium carbonate. Maybe one of the resident chemists can weigh in. @rgranger are you listening?

https://images.thdstatic.com/catalog/pdfImages/f5/f5a594f2-c5d1-4a52-8174-3b1edd590e9c.pdf

https://www.australiasomuchtosee.com/linked/msds_noflex.pdf

 

[Peggie Hall HeadMistress]

No vented loop necessary?

Good question...That depends on how high in the pumpout line you put the y-valve. If it's high enough above the waterline you might be able to get away without one.

There should always be a seacock on any below-waterline thru-hull--not for redundancy, for safety...and it should only be open while dumping the tank.

--Peggie

 

[rgranger]

Peggie, I don't have much if any of a sludge problem. The two products are essentially the same. The active ingredient both is
Sodium Carbonate Peroxyhydrate. TST adds salt, Noflex adds sodium carbonate. Maybe one of the resident chemists can weigh in. @rgranger are you listening?

2Na2CO3•3H2O2 has two different functionalities…it is similar to a hydrated salt but the “water” has an extra oxygen atom making it a hydrogen peroxide molecule. Peroxides form free radicals … and radicals can break down tannins and other organon molecules such as proteins. The sodium carbonate piece is a decent base and bases help break the ester linkage in fats. (Similar to how you make soap out of lard…). And soap is water soluble.

 

[Gene Neill]

Here's the new hold down bracket for the Thetford 550P:

 

[LakeShark]

@Gene Neill Don't forget we need pictures once it's installed too. You are a bit of a fiberglass guru at this point after the cockpit scuppers and various repairs over the years. Nice work!

 

[Peggie Hall HeadMistress]

My original intent was to use a manual waste pump, plumbed between a lockable Y valve and a through hull. But this type of toilet can leave solid waste pretty solid, for a pretty long time, presumably since the solids don't pass through any kind of a pump on their way to the holding tank.

Solid waste is 75% water and therefore dissolves very quickly in water...and all portapotties--portable and "pumpable"-- have a flush water reservoir which must be filled using a pitcher or jug (I recommend you keep a gallon milk jug aboard for this purpose) each time you come aboard or more often if necessary. Enough to rinse the bowl is automatically delivered with each flush. So you won't be "dry" flushing...at least you shouldn't be!

And btw...I strongly recommend that you rinse the tank using a jug or a hose during each pumpout.

--Peggie