Is 20' too far from toilet to holding tank?

[phorvati]

Well I'm putting an electric toilet. Does that mean the only issues is large amount of water for each flush? I'll read up about vacuflush. I am ready to move up from manual toilets

[Boatyarddog]

Originally Posted by phorvati

I plan to run 1-1/2" pvc sch40 pipe for most of it, and have small flexible sanitation hose section on each end to absorb vibration.

Remember that electric toilets also have limitations in the area of pushing waste.
Budget is a factor in head planning.
Really consider your options, careful planning is the key.
You really don't want to have to maintain the system to much.
Clearing the pipe of its contents is most important.
With sloping runs, gravity clears it, other systems require longer pump times, more water.
Look for a place you can fit a formed tank, or clear a space and fit an area for a tank, preferably lower than the head.
Remember, you'll have to empty this tank, so you'll need a deck fitting for the pump out, a macerator installed in line to the pump out line, will chew up the contents as well assist the pump out to shore side facility.
So, many possibilities.
Even a waste bladder is an option. Under floor, under sette, under v berth, ect.
Cheers,
SV Cloud Duster

[peghall]

Originally Posted by phorvati

Well I'm putting an electric toilet. Does that mean the only issues is large amount of water for each flush? I'll read up about vacuflush. I am ready to move up from manual toilets

Electric macerating toilets no longer use huge amounts flush water...most need as little as a liter, no more than two. Amperage draw is about 15 for most sea water versions, 10 for most pressurized flush water versions.

The top of the line all china "thrones" are available with flush controls that offer up to 4 choices--bring in water ahead of use, dry bowl, low water flush and "full" flush. The Raritan Marine Elegance Raritan Marine_Elegance Promo.pdf is the top rated electric toilet and can be found for about $600 WITH the optional "Smart Flush" Panel. The Raritan Sea Era Raritan SeaEra Promo Sheet is more basic, but is available as either a complete toilet or a "conversion" (everything but the bowl, seat and lid) Raritan SeaEra Conversion Promo Sheet

Raritan still builds everything in the US. All Jabsco equipment sold in the US is now made in Mexico with parts and materials sourced from China and other Asian countries.

[Cadence]

Originally Posted by Jim Cate

Consider that to properly flush out that long connecting pipe you will add around 6.5 liters of extra flush water to the holding tank every time you use the loo. Means more trips to the pump out, etc.

Jim

My guess would be sediment in the pipe after using the loo?

[fatherchronica]

It seems a long way to me. I once did the framing and foundation on an 6 unit 2 story office building addition to a like sized office building. The sewer connection ran the length of both buildings. The owner was a general building contractor and the plumber was another of his usual sub contractors as was I. The owner asked me to figure out why they new building had constant sewer blockages and needed power rooting almost monthly. In the end it turned out that the plumber used all the fall available which was over an inch per foot instead of the required 1/4 inch per foot. And the watery part of the effluent ran off so quickly that it didn't carry all the paper and stuff all the way to the street, and clumps built up very quickly and eventually caused overflowing blockages. I would want a professional, probably an engineer, to assure me before I trusted a 20 foot length of excrement to doo the right thing in a boat.

[onavegador]

Once I visited a Catana 401 Catamaran, the bathroom was installed forward in the starboard hull, the holding tank in the aft cabin. You could not imagine how badly it smelled inside.
Holding tanks, connecting pipes and hoses are the problem.

[redsky49]

Let me chime in again.

In Post #2, I stated that it probably would work, given proper slope and no traps in the routing. I didn't say that I recommended this approach. However, let's look a little closer to the problem:

In most applications, the head discharge will direct the affluent upwards, above the waterline, to a 'Y' valve, and then to a vacuum break/vented loop.

From this elevation, say 36" above reference point, and using a 2% slope, you could safely extend the waste discharge 20 ft, with less than a 5" drop in the pipe. [Note that a 2% slope will satisfy all US Plumbing Codes].

But boats are not always level, stuff happens, so lets increase the slope of the discharge to 5%, after all, the waste in this case has less propulsive force (you aren't sending several gallons of water or compressed air to help the solid matter on its way).

With a 5% slope, the pipe drop over 20'-0" distance is still only 12".

Since the entry to the holding tank is typically at or near the top, meeting the "invert elevation" of the holding tank is easily accomplished with only a 12" drop from vented loop to holding tank.

Additionally, my suspicion is that the PVC will generate less deposits along its length due to the smoother inner surface - as compared to most waste hose, including the premium brands. And less friction is always better for fluid flow.

While this seems to be a workable solution, and has some obvious benefits, my concerns are in the real world, not the theoretical basis.

How are you going to install a sizeable length of rigid pipe in an existing boat? Are you going to adhesive-weld many smaller segments, creating leak sources, as well as possible snag points, at every joint?

How are you going to handle (i.e., prevent) flexing of the rigid pipe? Do you have sufficient structural surplus such that you can drill installation holes the length of the pipe run? Or are you sacrificing interior spaces/storage to route this pipe?

While I am inclined to say "go for it", (you can't do much irreversible harm), I wonder if you have overlooked a simpler approach.

I mean, for centuries buckets have worked for mariners.

[US1Fountain]

Had a Jabsco Quiet Flush in my previous boat. In 5 yrs, all I ever had to do was replace the Joker valve once, other wise never any problem. The discharge hose is only 1" dia. You control the amount of water per flush.

Current boat has a VacuFlush. Supposed to use little water, not sure how clean the hoses get with little water. More parts to go wrong, more complicated. And then there is the wait time for it to rebuild the vacuum if a 2nd flush is required. If I hadnt replaced the vacuum pump motor and rebuilt or replaced every item in that system last month before I noticed the toilet bowl flange was cracked, which now is on on order, I would have jerked the complete system out and installed another Jabsco Quiet Flush, for half the cost. Simple, dependable and affordable.

[1Sunseeker]

I would think it sort of depends on the vertical drop.


What do you have to know to be a piping designer?
1. Pipe R round.
2. Waste water runs down hill.
3. Pay day is on Friday.

[David B]

Originally Posted by phorvati

So what do boats with two head usually do? Two holding tanks?

These days, generally yes.
With ours, the holding tanks are pretty well directly above the toilet. Line length would be about 1 metre in each case.

I suggest a long run is not good practice, unless you have room for a really decent sized holding tank (to take the extra flushing water required), AND, the tank would have to be gravity fed. Pushing waste along 20'/6m of line is problematic. Think of household waste plumbing - out and down.

[David B]

Originally Posted by US1Fountain

Had a Jabsco Quiet Flush in my previous boat. In 5 yrs, all I ever had to do was replace the Joker valve once, other wise never any problem. The discharge hose is only 1" dia. You control the amount of water per flush.

Current boat has a VacuFlush. Supposed to use little water, not sure how clean the hoses get with little water. More parts to go wrong, more complicated. And then there is the wait time for it to rebuild the vacuum if a 2nd flush is required. If I hadnt replaced the vacuum pump motor and rebuilt or replaced every item in that system last month before I noticed the toilet bowl flange was cracked, which now is on on order, I would have jerked the complete system out and installed another Jabsco Quiet Flush, for half the cost. Simple, dependable and affordable.

I will second that. The only thing wrong with them is the misleading name.

[David B]

Originally Posted by Boatyarddog

Remember that electric toilets also have limitations in the area of pushing waste.
Budget is a factor in head planning.
Really consider your options, careful planning is the key.
You really don't want to have to maintain the system to much.
Clearing the pipe of its contents is most important.
With sloping runs, gravity clears it, other systems require longer pump times, more water.
Look for a place you can fit a formed tank, or clear a space and fit an area for a tank, preferably lower than the head.
Remember, you'll have to empty this tank, so you'll need a deck fitting for the pump out, a macerator installed in line to the pump out line, will chew up the contents as well assist the pump out to shore side facility.
So, many possibilities.
Even a waste bladder is an option. Under floor, under sette, under v berth, ect.
Cheers,
SV Cloud Duster

Macerator at the base of the toilet is better - chews everything up before it goes into the tank. Then (ideally) gravity emptying of the tank when dumping at sea, so no pump required. Only pump then is the one at the dock pump-out station.

[Bleemus]

Is 20 feet too long . .

Yes.

[phorvati]

For this one, im going with composting toilet. Nature's head or airhead. It's a no brainer, especially given that there is already a functioning toilet close to a holding tank.

[peghall]

Current boat has a VacuFlush. Supposed to use little water, not sure how clean the hoses get with little water.

They don't..and neither does the pump. 99% of the problems with VacuFlush are caused by using too little water. I mentioned in post #12 that I've written a piece I call "VacuFlush 101" that explains how it works and how much water it really needs to keep it trouble free. I'll be glad to send it to you if you'll send me a PM that includes your email address (can't attach anything to a PM). Fwiw, I was a V/Flush dealer for nearly 10 years and it was also the toilet on my last 2 boats...so I'm intimately acquainted with it!

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein