MSD Portapotty plumbing, new install.

[Timo42]

Just bought a Sealand 974msd to replace a cheapo portapotty. I am going to install the pumpout fittings. Assuming the vent is required, where do I install it. Have seen drawings that seem to indicate it goes into the hull above the water line, but all the drawings I have seen include provisions for discharge overboard, which I am not interested in. What kind of fitting do I need, how high above the waterline should I make it, etc. Thanks, Tim

 

[Peggie Hall HeadMistress]

Install is simple...

All you need is a vent line and vent thru-hull, and a pumpout line and deck pumpout fitting.

The deck pumpout fitting goes in the side deck...make the line as short and straight as possible.

Where to put the vent depends on where the portapotty is gonna go. If under the v-berth, you'll want to run it forward out the hull just below the toe rail.

There should be instructions with it, btw.

 

[Timo42]

Thanks, location is next to the compression post, shouldn't be a problem to put the vent below the toerail there. Pumpout hose is going straight up to deck Read the instructions, they said to connect to fitting, no mention of suitable location.:bang:
Tim

 

[caguy]

Congrats on new potty. When is spash day?

Can hardly wait. It looks like a pretty good deal. Do you think 2.6 will be enough for a 4 day weekend? If you want some help installing let me know. I may do the same to mine.

 

[Peggie Hall HeadMistress]

Depends on the number of people using it

Is a 2.6 gal enough for a 4 day weekend?

2.6 gals is about 20-25 flushes...the average adult uses the toilet 5x/24 hrs. So while that's just barely big enough for one person continuously aboard for long weekend, only enough capacity for an overnighter for a couple continuously aboard. So you'd either have to spent a lot of time during a 4 day weekend in a slip so you can use marina facilities, or you're gonna need a second spare tank...or the larger 5-6 gal model that holds 50-60 flushes.

The footprint is the same for the 2-3 gal models and the 5-6 gal models...the only difference is the height, which can be a problem if the potty has to go under the v-berth or settee. That can sometimes (not always) be solved by removing the lid so it'll fit under the cushion. Since the tank is sealed, only the bowl is exposed..but nobody ever keeps the lid closed at home or on a marine toilet either, so that's no big deal.

So if you want enough capacity to spend at least a couple days away from shore facilities, you might want to take some measurements to see if the larger size will fit before you install the one you bought. Check out the Thetford models first. Thetford toilets

 

[Barnacle Bill]

Head vent

Usually the vent fitting used for a head vent is the same used for a gas tank vent. Most, but not all, have a head that is tear dropped and you can aim the opening towards the stern placed high near the gunwale so water does not go down when you heel over (not near the waterline). These vents often have little screens in them to keep the bugs out too. They are inexpensive and can be purchased in plastic or metal. Usually 5/8" us the hose size for vents on heads, but that might not be true with all head mfgs.

 

[Timo42]

Thanks Frank,I think you have done quite enough already, Peggy, I thought about the bigger one, but don't have enough headroom, Frank is the only one to use the old one, once, I may add a separate tank for overflow, there is room behind the head under the settee seat for a tank, if necessary. Thanks for the help

 

[Timo42]

One last question, the deck fitting came with a chain attached to the cap, that has to go right? I did see one at WM that had a locking cap, I can't get my mind around...I mean, who would...why would someone want to steal...
Thanks again for the help.
Tim

 

[Peggie Hall HeadMistress]

Yup...chain has to go

The only difference between fuel, water and waste deck fittings is what's stamped into the flange...and since water and fuel can use a chain to help prevent overboard loss, it's not unusual to find a chain on waste fittings too (which prob'ly explains why you saw a locking cap on a waste fitting). The chain needs to go, 'cuz it would prevent a pumpout from getting a seal...and if the pumpout can't seal, it can't pump the tank out.

Learn to put the cap in the cockpit or somewhere INSIDE the gunwhales immediately after removing it...don't just set it down next to the fitting unless you want to buy a lot of replacement caps.