Head/Holding tank below waterline - options?

[Beausoleil]

After I successfully replaced the forward head/holding tank system in Beausoleil, I'm ready to tackle the aft system. The two are totally independent - no common plumbing between the two.

The old system had everything below the waterline, and moving either the Lectra-San or the holding tank to above the waterline is a job I'm just not willing to tackle while we're living/actively cruising on the boat!

I'd like the option to discharge directly overboard when we're offshore, but introducing a third Y-valve to accomplish that would make it much too complicated for the average crew to operate properly. The attached PDF shows what I have in mind - a y-valve to select between discharging the head into the Lectra-San or into the holding tank. A second y-valve allows the tank to be pumped out via the deck fitting, or overboard via a tank pump.

Is there any way to simplify things?

[rebel heart]

I have a Y going from the toilet exhaust. One goes overboard, the other into the holding tank.

There's a Y on the exhaust of the holding tank, one going to the deck fitting for pumpouts, the other going to a mark v manual pump which goes overboard.

Both overboard lines (from the head and from the holding tank) have a vented loop on them, and come together in a T.

Seems to work pretty good, and is fairly straight forward.

Originally Posted by Beausoleil

Is there any way to simplify things?

I like your arrangement. An extra "Y" valve wouldn't buy you anything except more complexity.

You could make it even easier if you had a seperate holding tank fitting for the overboard discharge and the deck pumpout, but that might be too much to ask

Of course the devil is in the details, so put as much thought into your hose runs as you have into the schematic!

Good Luck!

Bill

[Paul L]

Why do you have two discharge through hulls? One should be sufficient.

Paul L

[Beausoleil]

Originally Posted by Paul L

Why do you have two discharge through hulls? One should be sufficient.

Paul L

Why does one climb a mountain? Same answer - because it's there!

Seriously, though - the old system used two through-hulls, and since I don't want to haul the boat to remove an unused one, I thought I'd use it - I figure that I'd be more liable to keep an eye on it than if it were just unused...

[GordMay]

There’s nothing wrong with your diagramed system.
Would it be practicable to pipe the system such that the Discharge Pump(s) is (are) located (schematically) between the Holding Tank and the Tank Discharge Y-Valve? This would allow the pump to be utilized for either deck or seawater discharge.

I presume that the Tank Vent(s) are omitted for clarity.

[Beausoleil]

Originally Posted by GordMay

...Would it be practicable to pipe the system such that the Discharge Pump(s) is (are) located (schematically) between the Holding Tank and the Tank Discharge Y-Valve? This would allow the pump to be utilized for either deck or seawater discharge.

I presume that the Tank Vent(s) are omitted for clarity.

Physically, it would be no problem to relocate the pumps, but why? I haven't come across a pumpout station that required an "assist" from a boat's plumbing, but I guess prudence could dictate it...

There is a tank vent in the drawing. Do you mean piping the vented loop vents to holding tank vents as seen in some plumbing schematics? I've never really understood those. I guess it's possible for the duck-bill valve in them to eventually stick in the open position due to salt crystals or such, so using a hose to capture and pipe any effluent overboard to me would seem to prevent one from sensing (via the olfactory test!) if a problem developed. But I could fit a hose to it and connect it to the tank vent hose with no problem.

As an aside, I wish it would be easy to locate the holding tank above the water line. We were able to do so with the forward head (we had some space on a very large shelf in the separate shower compartment - sweet, I know!), and it's been working flawlessly - with the exception of some under-sized wiring for the new Electro-Scan unit which I finally discovered when we were on the hook, running under batter power alone. The unit ran fine when the chargers floated the batteries at 13.7V, but when down even at 12.6V, the Electro-Scan would report a low amperage warning. Turns out the electrician ran 8 gauge wire rather than 4 or 6 per Raritan's guidlines... Will have to do the replacement myself next week...)

[Paul L]

Originally Posted by Beausoleil

Why does one climb a mountain? Same answer - because it's there!

Seriously, though - the old system used two through-hulls, and since I don't want to haul the boat to remove an unused one, I thought I'd use it - I figure that I'd be more liable to keep an eye on it than if it were just unused...

I'd still consider piping it all to one through hull. Then either think about future use for the other one, say a water input for a watermaker, or put it on your list to remove the extra hole in the boat on the next haulout.

Paul L

[Beausoleil]

Originally Posted by Paul L

I'd still consider piping it all to one through hull. Then either think about future use for the other one, say a water input for a watermaker, or put it on your list to remove the extra hole in the boat on the next haulout.

Paul L

Normally, I'd certainly think that would be the best option. Keeping the number of thru-hulls to a minimum is best.

However, in our situation, the thru-hull for the Lectra-San is next to it - actually on its left side (in the drawing I put it on the right because it makes the schematic neater). The Lectra-San is actually much closer to the head than the schematic would lead you to believe. The thru-hull for the holding tank is about 6' forward (to the right in the drawing) of the Lectra-San, right next to the holding tank. It makes the overall sanitation hose runs much shorter - less opportunity for odor, I believe. I would love to mount the holding tank much closer, but it just won't fit in that given space.

The attached drawings have been modified to show this a bit better.

And we already have a thru-hull for a watermaker. Replacing the old PUR PowerSurvivor 35 is on our to-do list.

[Paul L]

Beausoleil,
Like everything else you do on a boat, it is all a trade-off. While you might save 6 feet of output hose going back to the one through hull, you also add an extra anti-siphon value plus the hose length to get above and back down below the water line, along with an extra hole in the boat. You also add the extra maintenance of the anti-siphon value and the through hull seacock.

Of course I have no dog in this fight Just helping point out the trade-offs

Paul L

[GordMay]

Originally Posted by Beausoleil

1. Physically, it would be no problem to relocate the pumps, but why? I haven't come across a pumpout station that required an "assist" from a boat's plumbing, but I guess prudence could dictate it...
2.There is a tank vent in the drawing.

1. I withdraw the question & implied suggestion. The pump (as I proposed) would just add resistance to the deck pumpout circuit.
2. Sorry, I just didn't see the tank vent line.

[Beausoleil]

Originally Posted by Paul L

Beausoleil,
Like everything else you do on a boat, it is all a trade-off. While you might save 6 feet of output hose going back to the one through hull, you also add an extra anti-siphon value plus the hose length to get above and back down below the water line, along with an extra hole in the boat. You also add the extra maintenance of the anti-siphon value and the through hull seacock.

Of course I have no dog in this fight Just helping point out the trade-offs

Paul L

Thanks, Paul. Is this what you mean? Run the output of the Lectra-San into the outlet side, just before the pump?

That would make for a longer overall run. I'd have to make sure any guests aren't shy about pumping the head to ensure enough water is used, but it would give the option of using the pump to evacuate the output hose of the Lectra-San (and possibly the Lectra-San itself if I were adventurous enough to add a pickup tube to its outlet, which is currently not a standard feature from Raritan). And the outlet Y-valve would have to be set for the deck fitting (up position) to ensure a vacuum seal there, but that should be the default position, anyway.

Or were you thinking something else? I'm definitely open to any improvements. It's an iterative process...

[Paul L]

I'm not sure about the physical layout you have. When I was thinking of removing one through-hull, I was actually thinking about removing the other one and running iots output back to the left hand goes out.

Paul L

[Lodesman]

Jon,

Wouldn't it be simpler to run the head to the holding tank and from the holding tank have a dedicated line to the deck pump out and a second line to a y-valve splitting to the lectrasan and the manual pump-out?


Kevin