fresh water flush

[Dave]

Gentlemen,

Healthy disagreement and discussion is always welcome, we can all benefit from those discussions. However, I want to remind you that in all cases the expectation is civility and personal attacks are inconsistent with community norms. It is what we all expect of each other.

Fair Winds,
Dave
SBO Forum Admin

 

[Tally Ho]

If I may offer, a valve could be added just past the "T" takeoff to the head and this would allow fresh water (from the sink) to enter the head for a final rinse before leaving the boat.

View attachment 230579

As I think about this, how would I switch between sea water and the sink fresh water if the thruhull from the sink is above the water line? I couldn’t use that line for regular “sea water flushes” and then easily switch to a fresh water flush at the end of the day.

Greg

 

[dlochner]

As I think about this, how would I switch between sea water and the sink fresh water if the thruhull from the sink is above the water line? I couldn’t use that line for regular “sea water flushes” and then easily switch to a fresh water flush at the end of the day.

Greg

It would be a Y-Valve. The outlet goes to the pump, one leg goes to the sink drain the other to the seacock. Sort of backwards to the Y-valve on the discharge side.

 

[Peggie Hall HeadMistress]

Yes, keeping an aerobic tank helps to eliminate odors. But few, and I mean few, boats can keep their tanks aerobic enough because of build and design constraints.

"Build and design constraints" are easily overcome with a larger diameter vent line that may or may not need to be shortened and straightened, going to an an open "bulkhead fitting" thru-hull instead of the factory installed "vent" thru-hull that''s actually designed to keep sea water out of fuel and water tanks, so doesn't let the tank "breathe." Boat builders--who are the worst sanitation plumbers on the planet--use 'em on waste tank vent lines too because it costs 'em a few pennies less than the to use the same thing everywhere instead of using the right kind on waste tanks. Aeration is an excellent option that doesn't have to be expensive...many boat owners are DIYing aerators using bait well pumps and a few feet of "perforated" sanitation hose run across the inside of the tank near the bottom.

So overcoming "build and design restraints" isn't difficult...just requires the ability to think "outside the box" and a bit of a learning curve to know how to apply bio-physics 101 to holding tanks. And I'll be glad to help you do that.

--Peggie

 

[Tally Ho]

It would be a Y-Valve. The outlet goes to the pump, one leg goes to the sink drain the other to the seacock. Sort of backwards to the Y-valve on the discharge side.

Yes sir, that makes sense.

 

[Peggie Hall HeadMistress]

As I think about this, how would I switch between sea water and the sink fresh water if the thruhull from the sink is above the water line? I couldn’t use that line for regular “sea water flushes” and then easily switch to a fresh water flush at the end of the day.

Greg

It would be a Y-Valve. The outlet goes to the pump, one leg goes to the sink drain the other to the seacock. Sort of backwards to the Y-valve on the discharge side

Nope...and y'all are waaaay overthinking this. You would not be able to use the head sink drain thru-hull to pull in flush water...the head intake line would have to stay on the intake thru-hull. But you CAN tee a line off the head intake line to the sink drain line, it would just tee in a lot higher on the drain line because it would only be able to pull water out of the sink, same as it would when the thru-hull is closed on a below-waterline drain. That would only require putting a seacock or valve on the sink drain thru-hull to prevent water from the sink from going out its drain.

--Peggie

 

[dlochner]

It would be a Y-Valve. The outlet goes to the pump, one leg goes to the sink drain the other to the seacock. Sort of backwards to the Y-valve on the discharge side

Nope...and y'all are waaaay overthinking this. You would not be able to use the head sink drain thru-hull to pull in flush water...the head intake line would have to stay on the intake thru-hull. But you CAN tee a line off the head intake line to the sink drain line, it would just tee in a lot higher on the drain line because it would only be able to pull water out of the sink, same as it would when the thru-hull is closed on a below-waterline drain.

--Peggie

Since Greg's sink drain is above the water line, he would need to close the sink seacock and fill the sink with fresh water. A line Tee'd into the drain would then pull water from the sink into the toilet pump. Otherwise in the valve in the "normal" seawater position would pull water from the existing seacock. If his drain was below the water line, it would be a different issue.

 

[Peggie Hall HeadMistress]

I THINK that's what I said...

--Peggie

 

[dlochner]

I THINK that's what I said...

--Peggie

That's what I implied and clarified what I had meant.

 

[Tally Ho]

I think I am going to keep rinsing the head out with the shower head after a sail! Way easier and honestly, (probably because I am in the clean, fresh water of Lake Michigan), my head odor is not bad. I find a quick rinse and flushing out the discharge line is fine.

But thanks for the suggestions….if things ever change, I can redo some of the plumbing to get a true fresh water rinse through the whole system.

Thanks,

Greg

 

[kappykaplan]

fresh water of Kake Michigan

Sounds sweet!

 

[Tally Ho]

Since Greg's sink drain is above the water line, he would need to close the sink seacock and fill the sink with fresh water. A line Tee'd into the drain would then pull water from the sink into the toilet pump. Otherwise in the valve in the "normal" seawater position would pull water from the existing seacock. If his drain was below the water line, it would be a different issue.

I don’t have a seacock on the sink drain. So, I would need to add a valve to effectively close off the drain line, and have a T above that…so I could close the valve, fill the sink with fresh water, switch “something”…a Y valve I guess, to have the head use the sink drain for water.

Lots of screwing around and work to fix a problem I don’t really have

But I could do it if I felt the need.

Cheers,

Greg

 

[Tally Ho]

“Kake Michigan”

Sounds sweet!

Can’t blame that on spell check…. just my fat fingers typing on an ipad

I fixed my spelling

Greg

 

[colemj]

And I'll be glad to help you do that.

Thanks, but we don't use our holding tank, so don't have the issue. Aerators are a good solution for some. As for how easy it is to fix factory setups, I don't think you have much experience with catamarans? Their systems are often so horribly buried and a long way from anyplace reasonable to penetrate a hull. For example, ours are built into the middle of the bilge in each hull, with the vent line traveling 15' to the first place it can safely come out of the boat. Making it shorter and more direct would mean having a vent line directly in the middle of our hull passageway, or cutting through open space and dividing a cabin.

Since every bit helps for keeping a tank aerobic, fresh water goes a long way toward helping the aerobic microbes keep on top of the anaerobic ones.

Mark

 

[Peggie Hall HeadMistress]

Thanks, but we don't use our holding tank, so don't have the issue. Aerators are a good solution for some. As for how easy it is to fix factory setups, I don't think you have much experience with catamarans? Their systems are often so horribly buried and a long way from anyplace reasonable to penetrate a hull. For example, ours are built into the middle of the bilge in each hull, with the vent line traveling 15' to the first place it can safely come out of the boat. Making it shorter and more direct would mean having a vent line directly in the middle of our hull passageway, or cutting through open space and dividing a cabin.

Since every bit helps for keeping a tank aerobic, fresh water goes a long way toward helping the aerobic microbes keep on top of the anaerobic ones.

Unfortunately it doesn't, Oxygen is the only thing that does. But it does keep the plumbing a lot cleaner and all but eliminates mineral build in it. Aeration would introduce oxygen into the tank and is often the solution in systems that can't be modified to do that passively. There is a tank product--NoFlex Digestor-- that often works in tanks that aren't as well vented as they should be, but do allow some exchange of air withe gasses in the tank.

And yes, I've had considerable experience with catamarans, but none with the issues you describe.
-Peggie

 

[Ralph Johnstone]

As I think about this, how would I switch between sea water and the sink fresh water if the thruhull from the sink is above the water line? I couldn’t use that line for regular “sea water flushes” and then easily switch to a fresh water flush at the end of the day.

Hi Greg,

This is the alteration I made to my existing system although I didn't bother to install the hand drawn valve. My sink drain is below the water line and the thru-hull cock is easily accessible so no need.

When it comes time to rinse the system before leaving the boat for any length of time, in your case you would close the hand drawn valve and start running water into the sink.

Twist sideways to the head and close the sea water inlet valve and open the isolation valve to the pump inlet line. Pump away with fresh rinse water.

The advantage of this setup is that everything is done within the confines of the head and only takes a short time. Only the boat owner would be doing this final rinse.

 

[Tally Ho]

Hi Greg,

This is the alteration I made to my existing system although I didn't bother to install the hand drawn valve. My sink drain is below the water line and the thru-hull cock is easily accessible so no need.

View attachment 230615

When it comes time to rinse the system before leaving the boat for any length of time, in your case you would close the hand drawn valve and start running water into the sink.

Twist sideways to the head and close the sea water inlet valve and open the isolation valve to the pump inlet line. Pump away with fresh rinse water.

View attachment 230617

The advantage of this setup is that everything is done within the confines of the head and only takes a short time. Only the boat owner would be doing this final rinse.

Love your annotations and photos Ralph. Certainly helps me visualize the setup.

Thank you,

Greg

 

[Clutch Cargo]

RE: "This is the alteration I made to my existing system although I didn't bother to install the hand drawn valve. My sink drain is below the water line and the thru-hull cock is easily accessible so no need."

Very nice. If my configuration was conducive, I'd do the same thing.

 

[Arrgh]

Wow! I didn't think this would gain so much attention. Interesting to read everyone's solution. I think some of the designs with extra valves and sea cocks etc. is more complex than just adding a fresh water tank. I could add a tank right next to where the through hull is now and use the same plumbing...done.

 

[jssailem]

Whatever resolves your need makes sense.