MSD plumbing

[Joe]

Hi Peggy.... I'm reworking the MSD plumbing to accomdate a new head. Question 1: Is it recommended to apply sealant on the discharge hose fittings....i.e. y-valve, holding tank, etc. On my boat, the old stuff had some kind of gunk... pipe dope maybe?

Quesion 2: I want to relocate the plastic holding tank's vent elbow/nipple. Is the threaded end of the nipple self-tapping? and again, does it need sealant?

Question 3: I have to expand the small, diagonal facing platform that the old head sat on....(it's on the cat27) and I'm having trouble adapting the new section to be exactly flush with the old. I am considering fabricating a rubber gasket to insert between the uneven platform and the head's base for a neater all round fit. Am I on the right track here? ....or do I need an additional, single solid layer over the entire platform.

Thanks for your advice.... Joe

 

[Peggie Hall HeadMistress]

Question 1: Is it recommended to apply sealant on the discharge hose fittings....i.e. y-valve, holding tank, etc. On my boat, the old stuff had some kind of gunk... pipe dope maybe?

Nope...NO sealant of any kind on hose connections...just two hose clamps, with screws 180 degrees apart. Teflon tape only on threaded fittings.

Quesion 2: I want to relocate the plastic holding tank's vent elbow/nipple. Is the threaded end of the nipple self-tapping? and again, does it need sealant?

No...to both questions. That'll require a hole saw and li'l gadget called the Uniseal UNISEAL (Scroll through all the pages to see how it works and the price list) and a piece of PVC pipe. You'll find discussions about doing this in the HM forum. And as long as you're doing this, it would be an excellent time to upgrade the vent to 1"...which will require a new vent thru-hull. It should be a plain ol' bulkhead fitting, not "vent" thru-hull.

Question 3: I have to expand the small, diagonal facing platform that the old head sat on....(it's on the cat27) and I'm having trouble adapting the new section to be exactly flush with the old. I am considering fabricating a rubber gasket to insert between the uneven platform and the head's base for a neater all round fit. Am I on the right track here? ....or do I need an additional, single solid layer over the entire platform.

Well...it'll work, but if you shower in the head, it's not a good idea because water can run under the toilet base, which can result in a rotted head sole. So you really want the toilet base to sit "firmly" on the sole, with a sealant around it to keep water out from under it. And btw...that also requires paying a LOT more attention to the condition of the sealant than 99% of owners do so ithat it doesn't leak and result in even worse rot than nothing.

 

[Joe]

Thanks so much, Peggy. One follow up question: Can the new vent be located on top of the tank, or should it be on the side, near the top edge, as it is currently.

I really appreciate the time and expertise you provide this forum. Joe

 

[Peggie Hall HeadMistress]

Not only can be, but SHOULD be on the top of the tank...

And away from hull, closest to the centerline...to prevent waste from spilling out the vent when the boat is heeled.

Where's the tank located in the boat?

 

[Joe]

And away from hull, closest to the centerline...to prevent waste from spilling out the vent when the boat is heeled.

Where's the tank located in the boat?

It's under the forward dinette settee a foot behind the starboard bulkhead. The outboard side of the tank is pretty close to the hull, so I'll reconsider the remount and try to work with the existing outlet...or tap a new one directly above it. I'm trying to give better access to the through hulls, which are direcly under the forward part of the tank.

 

[Peggie Hall HeadMistress]

Where's the head?

Is it forward in the cabin or aft? If forward, what's under your v-berth?