Question on Plumbing - 81 Catalina 27

[tomlang63]

I have a 81 Cat 27, and a quick question on head plumbing. I have a holding tank with the normal Y-valve setup(never discharge). My question is this, i have a thru hull inlet that feeds the supply side of my head. Inline with that hose is a T fitting that also connects to the drain in my head for for the sink, so that when I flush on the head, it would pull any water in the line from the sink, or it would also drain via gravity back out via the thru hull. My question is simple, is this the proper setup? I sometimes notice that when pumping the head i don't get good water flow and think that may be due to the vent that the sink drain creates by being connected to the inlet for the head. If i were to put a shutoff valve in the hose from the sink drain would that solve the issue?

Thanks.

 

[Ed Schenck]

So a previous owner gave you the ability to flush with fresh water? You fill the sink with water and draw it from the drain? Then there must be a shutoff valve from the sink to overboard that has to be closed. Is that the case? With that valve closed could you just use the stopper in the sink drain? Certainly an inline valve right by that 'T' would work. I am sure others will have better ideas for replumbing.

 

[Peggie Hall HeadMistress]

No need for any shutoff valve...

If the toilet is pulling air through the sink, just put a plug in the sink when needed.

To answer your question:
i have a thru hull inlet that feeds the supply side of my head. Inline with that hose is a T fitting that also connects to the drain in my head for for the sink, so that when I flush on the head, it would pull any water in the line from the sink, or it would also drain via gravity back out via the thru hull. My question is simple, is this the proper setup?

That's not how Catalina plumbed it, but teeing the head intake line into the head sink drain line is a great way to do it 'cuz it provides a safe source of fresh water to rinse the sea water out of the whole system, or even flush using fresh water.

However the PO who did install it, kinda overdid it. There's no need to keep the head intake connected to TWO thru-hull--the original head intake AND the sink drain. So I'd replumb it to take the head intake thru-hull out of the mix entirely...you can remove it and glass it over or use it for a washdown pump or any other purpose you like. All you need to do is tee the head intake line into the sink drain line just ahead of the thru-hull. That's it...that's all the plumbing needed. Flushing the toilet will pull in sea water, although you'll prob'ly still need the plug for sink. When you close up the boat at the end of a weekend aboard, after you've closed all the seacocks ( you DO close all the seacocks, right?), fill the sink with clean fresh water...do NOT put the plug in the sink...it'll fill up 'cuz the drain line is closed. Flush the toilet. Because the thru-hull is closed, the toilet will pull the water out of the sink, rinsing the sea water out of the whole system so it won't sit, stagnate and stink.

For your next project, you can get the tank vent line out of the rail stanchion and connected to a real thru-hull that can let you backflush the vent line every time you wash the boat, preventing it from becoming blocked.

 

[Joe]

Normally, you would tee the sink drain into the input line between the pump and bowl... letting gravity empty the sink into the bowl, them pump from there.

 

[Peggie Hall HeadMistress]

Never heard of doing it that way before

If you tee the sink drain into the line between the pump and bowl. (which, btw, is where the vented loop needs to go), fresh water from the sink wouldn't ever go through the pump to rinse all the sea water out of it, so there'd be no point in doing it 'cuz that's only real reason to tee the toilet intake into the sink drain line.

I suppose you COULD do something like that to cobble up a "fresh water manual toilet" but why? What would you gain by eliminating the "wet" mode? And it would require installing a valve to prevent gray water from going through the toilet--or any other water just draining into the toilet bowl if you only want to use the sink, not the toilet too.

 

[shipwreck66]

 

[Peggie Hall HeadMistress]

What????

Now we all have the vent down inside the anchor locker, at the bottom, under the wet rope.

Are you saying that the holding tank does NOT vent to the outside of the boat...that it vents into the anchor locker???

...but the vent leading up from the head just ends at the deck, was never carried through.

What vent from the head? The tank vent should be the only vent line in the system.

And the sink shouldn't have anything to do with the holding tank vent or any other sanitation system plumbing except MAYBE the head intake line...but that has nothing to do with the tank or any venting.

If if it's gonna be a lot easier to sort this out by talking instead of typing, send me an email (EMAIL pls, not PM!).