Installing a new MSD head

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Oct 10, 2009
1,047
Catalina 27 3657 Lake Monroe
I bought a boat last year which had an old portable MSD head in it. It was a Thetford and hadn't been used in many years- all the hoses were brittle and (gulp) the tank was still full. I disconnected the hoses, emptied the tank and chucked the whole thing into the trash.

Now I want to install a new one- here are a couple questions:

Which one? I'm looking at Thetford and Sealand (Dometic?). I've measured the space available and have determined what size (height) will work, probably something like a Sealand 974MSD. Having no experience, are Thetford and Sealand roughly equal brands? Is there some other brand?

Hoses. The old head had a nice pumpout hose with fittings at each end. It looked like maybe it was precut. All I can find is hose by the foot. Am I right to assume this kind of hose will work just as well (like Trident 102)? And is there any special kind of hose to use for the vent (like a heater hose, which is far easier to find here)?
 
Dec 2, 1997
8,949
- - LIttle Rock
I'd go with the Thetford and order it from the sbo.com online store.

The old system didn't have any precut/prepackaged hose & fittings...everything was purchased separately just as you'll have to do. Use sanitation hose for both the pumpout hose and the vent line...Trident 101 or 102 for the pumpout, Trident #148 for the vent line. Any hose not rated for sanitation is likely to permeate very quickly. And I'd use a plain ol' "bulkhead" or "mushroom" fitting for the vent thru-hull (see photo) instead of a "vent fitting"...'cuz it allows more air into the tank and also is much easier to keep the vent clear by backflushing each time you wash the boat and or pump out.
 

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Oct 10, 2009
1,047
Catalina 27 3657 Lake Monroe
Thanks!

I appreciate the advice, Peggy. Anything in particular that causes you to favor Thetford? I don't have any experience with either of them.
 
Oct 10, 2009
1,047
Catalina 27 3657 Lake Monroe
It's available from the online store here...your purchases from there support this site!
But Sealand is also available via the store. Is there something that you prefer about the Thetford?
Also, the head in our boat sits on a platform that is about 3-4 inches high. I'm thinking we need one with a smaller tank (about 12 inch ht.) to keep the height from making it uncomfortable (figuring 16 inches is about what a household toilet is).

That limits me to a Thetford MSD 735 if I understand correctly.
 
Dec 2, 1997
8,949
- - LIttle Rock
They're equal quality..I think the Thetford may cost a little less. So pick the one you like...and I think you've done that.

It's just a portapotty!:D
 
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